diff --git a/CMakeLists.txt b/CMakeLists.txt
index b345e659..b0034179 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,6 +8,7 @@ ADD_BOOST(filesystem system thread)
 TARGET_LINK_LIBRARIES(${BII_BLOCK_TARGET} INTERFACE rt)
 
 ACTIVATE_CPP14()
+ENABLE_STYLE_WARNINGS()
 
 # You can safely delete lines from here...
 
diff --git a/appveyor.yml b/appveyor.yml
new file mode 100644
index 00000000..cff5981a
--- /dev/null
+++ b/appveyor.yml
@@ -0,0 +1,37 @@
+version: 0.9.{build}
+os: Visual Studio 2015 RC
+ 
+install:
+  - ps: wget http://www.cmake.org/files/v3.2/cmake-3.2.2-win32-x86.zip -OutFile cmake.zip
+  - cmd: echo "Unzipping cmake..."
+  - cmd: 7z x cmake.zip -o"C:\Program Files (x86)\" -y > nul
+  - cmd: set PATH=%PATH:CMake 2.8\bin=%;C:\Program Files (x86)\cmake-3.0.2-win32-x86\bin
+  - cmd: cmake --version
+  - cmd: echo "Downloading biicode..."
+  - ps: wget http://www.biicode.com/downloads/latest/win -OutFile bii-win.exe
+  - cmd: bii-win.exe /VERYSILENT
+  - cmd: set PATH=%PATH%;C:\Program Files (x86)\BiiCode\bii
+  - cmd: bii -v
+  - cmd: del bii-win.exe
+  - cmd: del cmake.zip
+ 
+before_build:
+  - cmd: bii init -L
+    # copy files and folders
+  - cmd: dir
+#  - cmd: echo xcopy "%APPVEYOR_BUILD_FOLDER%" blocks\%block_user%\%block_name%\ /e
+  - cmd: bii configure -G "Visual Studio 14 2015"
+ 
+build_script:
+  - cmd: bii build
+ 
+test_script:
+  - cmd: cd bin
+  - cmd: amalulla_cpp-expression-parser_test-shunting-yard.exe
+
+environment:
+  block_user:
+    "messmer"
+  block_name:
+    "blockstore"
+
diff --git a/biicode.conf b/biicode.conf
index 89337881..815f499f 100644
--- a/biicode.conf
+++ b/biicode.conf
@@ -1,13 +1,12 @@
 # Biicode configuration file
 
 [requirements]
-	 cryptopp/cryptopp: 8
+	 cryptopp/cryptopp: 9
 	 google/gmock: 2
-	 google/gtest: 10
+	 google/gtest: 11
 	 messmer/cmake: 3
 	 messmer/cpp-utils: 2
 	 messmer/parallelaccessstore: 0
-	 messmer/tempfile: 4
 
 [parent]
 	messmer/blockstore: 1
diff --git a/implementations/caching/Cache.cpp b/implementations/caching/Cache.cpp
deleted file mode 100644
index d3a9dba1..00000000
--- a/implementations/caching/Cache.cpp
+++ /dev/null
@@ -1,56 +0,0 @@
-#include "Cache.h"
-#include "PeriodicTask.h"
-
-using std::unique_ptr;
-using std::make_unique;
-using std::mutex;
-using std::lock_guard;
-using std::pair;
-
-namespace blockstore {
-namespace caching {
-
-constexpr uint32_t Cache::MAX_ENTRIES;
-constexpr double Cache::PURGE_LIFETIME_SEC;
-constexpr double Cache::PURGE_INTERVAL;
-constexpr double Cache::MAX_LIFETIME_SEC;
-
-Cache::Cache(): _cachedBlocks(), _timeoutFlusher(nullptr) {
-  //Don't initialize timeoutFlusher in the initializer list,
-  //because it then might already call Cache::popOldEntries() before Cache is done constructing
-  _timeoutFlusher = make_unique<PeriodicTask>(std::bind(&Cache::_popOldEntries, this), PURGE_INTERVAL);
-}
-
-Cache::~Cache() {
-}
-
-unique_ptr<Block> Cache::pop(const Key &key) {
-  lock_guard<mutex> lock(_mutex);
-  auto found = _cachedBlocks.pop(key);
-  if (found.get() == nullptr) {
-    return nullptr;
-  }
-  auto block = found->releaseBlock();
-  return block;
-}
-
-void Cache::push(unique_ptr<Block> block) {
-  lock_guard<mutex> lock(_mutex);
-  assert(_cachedBlocks.size() <= MAX_ENTRIES);
-  if (_cachedBlocks.size() == MAX_ENTRIES) {
-    _cachedBlocks.pop();
-    assert(_cachedBlocks.size() == MAX_ENTRIES-1);
-  }
-  Key key = block->key();
-  _cachedBlocks.push(key, make_unique<CacheEntry>(std::move(block)));
-}
-
-void Cache::_popOldEntries() {
-  lock_guard<mutex> lock(_mutex);
-  while(_cachedBlocks.size() > 0 && _cachedBlocks.peek().ageSeconds() > PURGE_LIFETIME_SEC) {
-	_cachedBlocks.pop();
-  }
-}
-
-}
-}
diff --git a/implementations/caching/Cache.h b/implementations/caching/Cache.h
deleted file mode 100644
index 7839b086..00000000
--- a/implementations/caching/Cache.h
+++ /dev/null
@@ -1,44 +0,0 @@
-#pragma once
-#ifndef MESSMER_BLOCKSTORE_IMPLEMENTATIONS_CACHING_CACHE_H_
-#define MESSMER_BLOCKSTORE_IMPLEMENTATIONS_CACHING_CACHE_H_
-
-#include "CacheEntry.h"
-#include "QueueMap.h"
-#include "../../interface/Block.h"
-#include <memory>
-#include <mutex>
-
-namespace blockstore {
-namespace caching {
-class PeriodicTask;
-
-//TODO Test
-//TODO Also throw blocks out after a timeout
-
-class Cache {
-public:
-  static constexpr uint32_t MAX_ENTRIES = 1000;
-  //TODO Experiment with good values
-  static constexpr double PURGE_LIFETIME_SEC = 0.5; //When an entry has this age, it will be purged from the cache
-  static constexpr double PURGE_INTERVAL = 0.5; // With this interval, we check for entries to purge
-  static constexpr double MAX_LIFETIME_SEC = PURGE_LIFETIME_SEC + PURGE_INTERVAL; // This is the oldest age an entry can reach (given purging works in an ideal world, i.e. with the ideal interval and in zero time)
-
-  Cache();
-  virtual ~Cache();
-
-  void push(std::unique_ptr<Block> block);
-  std::unique_ptr<Block> pop(const Key &key);
-
-private:
-  void _popOldEntries();
-
-
-  mutable std::mutex _mutex;
-  QueueMap<Key, CacheEntry> _cachedBlocks;
-  std::unique_ptr<PeriodicTask> _timeoutFlusher;
-};
-
-}
-}
-
-#endif
diff --git a/implementations/caching/CacheEntry.cpp b/implementations/caching/CacheEntry.cpp
deleted file mode 100644
index 0ca41a63..00000000
--- a/implementations/caching/CacheEntry.cpp
+++ /dev/null
@@ -1,2 +0,0 @@
-#include "CacheEntry.h"
-#include "../../interface/Block.h"
diff --git a/implementations/caching/CachingBlockStore.cpp b/implementations/caching/CachingBlockStore.cpp
index 0e152f37..67d841ea 100644
--- a/implementations/caching/CachingBlockStore.cpp
+++ b/implementations/caching/CachingBlockStore.cpp
@@ -9,6 +9,7 @@
 using std::unique_ptr;
 using std::make_unique;
 using cpputils::dynamic_pointer_move;
+using cpputils::Data;
 
 namespace blockstore {
 namespace caching {
@@ -27,13 +28,16 @@ unique_ptr<Block> CachingBlockStore::tryCreate(const Key &key, Data data) {
 }
 
 unique_ptr<Block> CachingBlockStore::load(const Key &key) {
-  auto block = _cache.pop(key);
-  if (block.get() != nullptr) {
-    return make_unique<CachedBlock>(std::move(block), this);
-  }
-  block = _baseBlockStore->load(key);
-  if (block.get() == nullptr) {
-    return nullptr;
+  boost::optional<unique_ptr<Block>> optBlock = _cache.pop(key);
+  unique_ptr<Block> block;
+  //TODO an optional<> class with .getOrElse() would make this code simpler. boost::optional<>::value_or_eval didn't seem to work with unique_ptr members.
+  if (optBlock) {
+    block = std::move(*optBlock);
+  } else {
+    block = _baseBlockStore->load(key);
+    if (block.get() == nullptr) {
+      return nullptr;
+    }
   }
   return make_unique<CachedBlock>(std::move(block), this);
 }
@@ -52,12 +56,12 @@ void CachingBlockStore::remove(std::unique_ptr<Block> block) {
 }
 
 uint64_t CachingBlockStore::numBlocks() const {
-  //TODO Add number of NewBlock instances
   return _baseBlockStore->numBlocks() + _numNewBlocks;
 }
 
 void CachingBlockStore::release(unique_ptr<Block> block) {
-  _cache.push(std::move(block));
+  Key key = block->key();
+  _cache.push(key, std::move(block));
 }
 
 std::unique_ptr<Block> CachingBlockStore::tryCreateInBaseStore(const Key &key, Data data) {
diff --git a/implementations/caching/CachingBlockStore.h b/implementations/caching/CachingBlockStore.h
index bf9adbc5..073ecd97 100644
--- a/implementations/caching/CachingBlockStore.h
+++ b/implementations/caching/CachingBlockStore.h
@@ -2,32 +2,31 @@
 #ifndef BLOCKSTORE_IMPLEMENTATIONS_CACHING_CACHINGBLOCKSTORE_H_
 #define BLOCKSTORE_IMPLEMENTATIONS_CACHING_CACHINGBLOCKSTORE_H_
 
-#include "Cache.h"
+#include "cache/Cache.h"
 #include "../../interface/BlockStore.h"
 
 namespace blockstore {
 namespace caching {
 
-//TODO Rename this to CachingBlockStore and the other one to something else
 //TODO Check that this blockstore allows parallel destructing of blocks (otherwise we won't encrypt blocks in parallel)
 class CachingBlockStore: public BlockStore {
 public:
-  CachingBlockStore(std::unique_ptr<BlockStore> baseBlockStore);
+  explicit CachingBlockStore(std::unique_ptr<BlockStore> baseBlockStore);
 
   Key createKey() override;
-  std::unique_ptr<Block> tryCreate(const Key &key, Data data) override;
+  std::unique_ptr<Block> tryCreate(const Key &key, cpputils::Data data) override;
   std::unique_ptr<Block> load(const Key &key) override;
   void remove(std::unique_ptr<Block> block) override;
   uint64_t numBlocks() const override;
 
   void release(std::unique_ptr<Block> block);
 
-  std::unique_ptr<Block> tryCreateInBaseStore(const Key &key, Data data);
+  std::unique_ptr<Block> tryCreateInBaseStore(const Key &key, cpputils::Data data);
   void removeFromBaseStore(std::unique_ptr<Block> block);
 
 private:
   std::unique_ptr<BlockStore> _baseBlockStore;
-  Cache _cache;
+  Cache<Key, std::unique_ptr<Block>> _cache;
   uint32_t _numNewBlocks;
 
   DISALLOW_COPY_AND_ASSIGN(CachingBlockStore);
diff --git a/implementations/caching/NewBlock.cpp b/implementations/caching/NewBlock.cpp
index edbfeb61..ee8837d3 100644
--- a/implementations/caching/NewBlock.cpp
+++ b/implementations/caching/NewBlock.cpp
@@ -3,6 +3,7 @@
 
 using std::unique_ptr;
 using std::make_unique;
+using cpputils::Data;
 
 namespace blockstore {
 namespace caching {
diff --git a/implementations/caching/NewBlock.h b/implementations/caching/NewBlock.h
index d71dbf69..5b2b69ac 100644
--- a/implementations/caching/NewBlock.h
+++ b/implementations/caching/NewBlock.h
@@ -3,7 +3,7 @@
 #define BLOCKSTORE_IMPLEMENTATIONS_CACHING_NEWBLOCK_H_
 
 #include "../../interface/BlockStore.h"
-#include "../../utils/Data.h"
+#include <messmer/cpp-utils/data/Data.h>
 
 #include "messmer/cpp-utils/macros.h"
 #include <memory>
@@ -20,7 +20,7 @@ class CachingBlockStore;
 // It only exists in the cache and it is created in the base block store when destructed.
 class NewBlock: public Block {
 public:
-  NewBlock(const Key &key, Data data, CachingBlockStore *blockStore);
+  NewBlock(const Key &key, cpputils::Data data, CachingBlockStore *blockStore);
   virtual ~NewBlock();
 
   const void *data() const override;
@@ -35,7 +35,7 @@ public:
 
 private:
   CachingBlockStore *_blockStore;
-  Data _data;
+  cpputils::Data _data;
   std::unique_ptr<Block> _baseBlock;
   bool _dataChanged;
 
diff --git a/implementations/caching/QueueMap.h b/implementations/caching/QueueMap.h
deleted file mode 100644
index 758b2bd4..00000000
--- a/implementations/caching/QueueMap.h
+++ /dev/null
@@ -1,78 +0,0 @@
-#pragma once
-#ifndef MESSMER_BLOCKSTORE_IMPLEMENTATIONS_CACHING2_MAP_H_
-#define MESSMER_BLOCKSTORE_IMPLEMENTATIONS_CACHING2_MAP_H_
-
-#include <memory>
-#include <unordered_map>
-#include <cassert>
-
-namespace blockstore {
-namespace caching {
-
-//TODO Test
-//TODO Move to utils
-template<class Key, class Value>
-class QueueMap {
-public:
-  QueueMap(): _entries(), _sentinel(nullptr, nullptr, &_sentinel, &_sentinel) {
-  }
-  virtual ~QueueMap() {}
-
-  void push(const Key &key, std::unique_ptr<Value> value) {
-    auto newEntry = std::make_unique<Entry>(&key, std::move(value), _sentinel.prev, &_sentinel);
-    _sentinel.prev->next = newEntry.get();
-    _sentinel.prev = newEntry.get();
-    auto insertResult = _entries.emplace(key, std::move(newEntry));
-    assert(insertResult.second == true);
-  }
-
-  std::unique_ptr<Value> pop(const Key &key) {
-    auto found = _entries.find(key);
-    if (found == _entries.end()) {
-      return nullptr;
-    }
-    _removeFromQueue(found->second.get());
-    auto value = std::move(found->second->value);
-    _entries.erase(found);
-    return value;
-  }
-
-  std::unique_ptr<Value> pop() {
-    return pop(*_sentinel.next->key);
-  }
-
-  const Value &peek() {
-	return *_sentinel.next->value;
-  }
-
-  uint32_t size() {
-    return _entries.size();
-  }
-
-private:
-  struct Entry {
-    Entry(const Key *key_, std::unique_ptr<Value> value_, Entry *prev_, Entry *next_): key(nullptr), value(std::move(value_)), prev(prev_), next(next_) {
-      if (key_ != nullptr) {
-        key = std::make_unique<Key>(*key_);
-      }
-    }
-    std::unique_ptr<Key> key;
-    std::unique_ptr<Value> value;
-    Entry *prev;
-    Entry *next;
-  };
-
-  void _removeFromQueue(Entry *entry) {
-    entry->prev->next = entry->next;
-    entry->next->prev = entry->prev;
-  }
-
-  //TODO Double indirection unique_ptr<Entry> and Entry has unique_ptr<Value>. Necessary?
-  std::unordered_map<Key, std::unique_ptr<Entry>> _entries;
-  Entry _sentinel;
-};
-
-}
-}
-
-#endif
diff --git a/implementations/caching/cache/Cache.cpp b/implementations/caching/cache/Cache.cpp
new file mode 100644
index 00000000..2d464949
--- /dev/null
+++ b/implementations/caching/cache/Cache.cpp
@@ -0,0 +1 @@
+#include "Cache.h"
diff --git a/implementations/caching/cache/Cache.h b/implementations/caching/cache/Cache.h
new file mode 100644
index 00000000..951c8f66
--- /dev/null
+++ b/implementations/caching/cache/Cache.h
@@ -0,0 +1,86 @@
+#pragma once
+#ifndef MESSMER_BLOCKSTORE_IMPLEMENTATIONS_CACHING_CACHE_H_
+#define MESSMER_BLOCKSTORE_IMPLEMENTATIONS_CACHING_CACHE_H_
+
+#include "CacheEntry.h"
+#include "QueueMap.h"
+#include "PeriodicTask.h"
+#include <memory>
+#include <mutex>
+#include <boost/optional.hpp>
+
+namespace blockstore {
+namespace caching {
+
+template<class Key, class Value>
+class Cache {
+public:
+  static constexpr uint32_t MAX_ENTRIES = 1000;
+  //TODO Experiment with good values
+  static constexpr double PURGE_LIFETIME_SEC = 0.5; //When an entry has this age, it will be purged from the cache
+  static constexpr double PURGE_INTERVAL = 0.5; // With this interval, we check for entries to purge
+  static constexpr double MAX_LIFETIME_SEC = PURGE_LIFETIME_SEC + PURGE_INTERVAL; // This is the oldest age an entry can reach (given purging works in an ideal world, i.e. with the ideal interval and in zero time)
+
+  Cache();
+  virtual ~Cache();
+
+  void push(const Key &key, Value value);
+  boost::optional<Value> pop(const Key &key);
+
+private:
+  void _popOldEntries();
+
+  mutable std::mutex _mutex;
+  QueueMap<Key, CacheEntry<Key, Value>> _cachedBlocks;
+  std::unique_ptr<PeriodicTask> _timeoutFlusher;
+};
+
+template<class Key, class Value> constexpr uint32_t Cache<Key, Value>::MAX_ENTRIES;
+template<class Key, class Value> constexpr double Cache<Key, Value>::PURGE_LIFETIME_SEC;
+template<class Key, class Value> constexpr double Cache<Key, Value>::PURGE_INTERVAL;
+template<class Key, class Value> constexpr double Cache<Key, Value>::MAX_LIFETIME_SEC;
+
+template<class Key, class Value>
+Cache<Key, Value>::Cache(): _cachedBlocks(), _timeoutFlusher(nullptr) {
+  //Don't initialize timeoutFlusher in the initializer list,
+  //because it then might already call Cache::popOldEntries() before Cache is done constructing
+  _timeoutFlusher = std::make_unique<PeriodicTask>(std::bind(&Cache::_popOldEntries, this), PURGE_INTERVAL);
+}
+
+template<class Key, class Value>
+Cache<Key, Value>::~Cache() {
+}
+
+template<class Key, class Value>
+boost::optional<Value> Cache<Key, Value>::pop(const Key &key) {
+  std::lock_guard<std::mutex> lock(_mutex);
+  auto found = _cachedBlocks.pop(key);
+  if (!found) {
+    return boost::none;
+  }
+  return found->releaseValue();
+}
+
+template<class Key, class Value>
+void Cache<Key, Value>::push(const Key &key, Value value) {
+  std::lock_guard<std::mutex> lock(_mutex);
+  assert(_cachedBlocks.size() <= MAX_ENTRIES);
+  if (_cachedBlocks.size() == MAX_ENTRIES) {
+    _cachedBlocks.pop();
+    assert(_cachedBlocks.size() == MAX_ENTRIES-1);
+  }
+  _cachedBlocks.push(key, CacheEntry<Key, Value>(std::move(value)));
+}
+
+template<class Key, class Value>
+void Cache<Key, Value>::_popOldEntries() {
+  std::lock_guard<std::mutex> lock(_mutex);
+  while(_cachedBlocks.size() > 0 && _cachedBlocks.peek()->ageSeconds() > PURGE_LIFETIME_SEC) {
+    _cachedBlocks.pop();
+  }
+}
+
+}
+}
+
+#endif
diff --git a/implementations/caching/cache/CacheEntry.cpp b/implementations/caching/cache/CacheEntry.cpp
new file mode 100644
index 00000000..a3420ac8
--- /dev/null
+++ b/implementations/caching/cache/CacheEntry.cpp
@@ -0,0 +1 @@
+#include "CacheEntry.h"
diff --git a/implementations/caching/CacheEntry.h b/implementations/caching/cache/CacheEntry.h
similarity index 68%
rename from implementations/caching/CacheEntry.h
rename to implementations/caching/cache/CacheEntry.h
index 7c11f0c0..b49ba970 100644
--- a/implementations/caching/CacheEntry.h
+++ b/implementations/caching/cache/CacheEntry.h
@@ -8,12 +8,12 @@
 #include <boost/date_time/posix_time/posix_time_types.hpp>
 
 namespace blockstore {
-class Block;
 namespace caching {
 
+template<class Key, class Value>
 class CacheEntry {
 public:
-  CacheEntry(std::unique_ptr<Block> block): _lastAccess(currentTime()), _block(std::move(block)) {
+  explicit CacheEntry(Value value): _lastAccess(currentTime()), _value(std::move(value)) {
   }
 
   CacheEntry(CacheEntry &&) = default;
@@ -22,22 +22,13 @@ public:
     return ((double)(currentTime() - _lastAccess).total_nanoseconds()) / ((double)1000000000);
   }
 
-  std::unique_ptr<Block> releaseBlock() {
-    return std::move(_block);
-  }
-
-  void setNextEntry(const CacheEntry *entry) {
-    _nextEntry = entry;
-  }
-
-  const CacheEntry *nextEntry() {
-    return _nextEntry;
+  Value releaseValue() {
+    return std::move(_value);
   }
 
 private:
   boost::posix_time::ptime _lastAccess;
-  std::unique_ptr<Block> _block;
-  const CacheEntry *_nextEntry;
+  Value _value;
 
   static boost::posix_time::ptime currentTime() {
 	return boost::posix_time::microsec_clock::local_time();
diff --git a/implementations/caching/PeriodicTask.cpp b/implementations/caching/cache/PeriodicTask.cpp
similarity index 62%
rename from implementations/caching/PeriodicTask.cpp
rename to implementations/caching/cache/PeriodicTask.cpp
index 1b260530..273bb15e 100644
--- a/implementations/caching/PeriodicTask.cpp
+++ b/implementations/caching/cache/PeriodicTask.cpp
@@ -9,17 +9,18 @@ namespace caching {
 
 PeriodicTask::PeriodicTask(function<void ()> task, double intervalSec) : _thread(), _task(task), _intervalSec(intervalSec) {
   _thread = boost::thread([this]() {
-	boost::chrono::nanoseconds interval((uint64_t)(UINT64_C(1000000000) * _intervalSec));
-	try {
+    boost::chrono::nanoseconds interval((uint64_t)(UINT64_C(1000000000) * _intervalSec));
+    try {
       while(true) {
         boost::this_thread::sleep_for(interval);
         _task();
       }
-	} catch (const boost::thread_interrupted &e) {
-	  //Do nothing, exit thread.
-	} catch (...) {
-	  cerr << "PeriodicTask crashed" << endl;
-	}
+    } catch (const boost::thread_interrupted &e) {
+      //Do nothing, exit thread.
+    } catch (...) {
+      //TODO Think about logging
+      cerr << "PeriodicTask crashed" << endl;
+    }
   });
 }
 
diff --git a/implementations/caching/PeriodicTask.h b/implementations/caching/cache/PeriodicTask.h
similarity index 96%
rename from implementations/caching/PeriodicTask.h
rename to implementations/caching/cache/PeriodicTask.h
index 4ad221e2..6a0955e6 100644
--- a/implementations/caching/PeriodicTask.h
+++ b/implementations/caching/cache/PeriodicTask.h
@@ -7,7 +7,6 @@
 namespace blockstore {
 namespace caching {
 
-//TODO Test cases
 class PeriodicTask {
 public:
 	PeriodicTask(std::function<void ()> task, double intervalSec);
diff --git a/implementations/caching/QueueMap.cpp b/implementations/caching/cache/QueueMap.cpp
similarity index 100%
rename from implementations/caching/QueueMap.cpp
rename to implementations/caching/cache/QueueMap.cpp
diff --git a/implementations/caching/cache/QueueMap.h b/implementations/caching/cache/QueueMap.h
new file mode 100644
index 00000000..f412432b
--- /dev/null
+++ b/implementations/caching/cache/QueueMap.h
@@ -0,0 +1,105 @@
+#pragma once
+#ifndef MESSMER_BLOCKSTORE_IMPLEMENTATIONS_CACHING2_MAP_H_
+#define MESSMER_BLOCKSTORE_IMPLEMENTATIONS_CACHING2_MAP_H_
+
+#include <memory>
+#include <unordered_map>
+#include <cassert>
+#include <boost/optional.hpp>
+#include <messmer/cpp-utils/macros.h>
+
+namespace blockstore {
+namespace caching {
+
+// A class that is a queue and a map at the same time. We could also see it as an addressable queue.
+template<class Key, class Value>
+class QueueMap {
+public:
+  QueueMap(): _entries(), _sentinel(&_sentinel, &_sentinel) {
+  }
+  virtual ~QueueMap() {
+    for (auto &entry : _entries) {
+      entry.second.release();
+    }
+  }
+
+  void push(const Key &key, Value value) {
+    auto newEntry = _entries.emplace(std::piecewise_construct, std::forward_as_tuple(key), std::forward_as_tuple(_sentinel.prev, &_sentinel));
+    if(newEntry.second != true) {
+      throw std::logic_error("There is already an element with this key");
+    }
+    newEntry.first->second.init(&newEntry.first->first, std::move(value));
+    //The following is ok, because std::unordered_map never invalidates pointers to its entries
+    _sentinel.prev->next = &newEntry.first->second;
+    _sentinel.prev = &newEntry.first->second;
+  }
+
+  boost::optional<Value> pop(const Key &key) {
+    auto found = _entries.find(key);
+    if (found == _entries.end()) {
+      return boost::none;
+    }
+    _removeFromQueue(found->second);
+    auto value = found->second.release();
+    _entries.erase(found);
+    return std::move(value);
+  }
+
+  boost::optional<Value> pop() {
+    if(_sentinel.next == &_sentinel) {
+      return boost::none;
+    }
+    return pop(*_sentinel.next->key);
+  }
+
+  boost::optional<const Value &> peek() {
+    if(_sentinel.next == &_sentinel) {
+      return boost::none;
+    }
+    return _sentinel.next->value();
+  }
+
+  uint32_t size() {
+    return _entries.size();
+  }
+
+private:
+  class Entry {
+  public:
+    Entry(Entry *prev_, Entry *next_): prev(prev_), next(next_), key(nullptr), _value() {
+    }
+    void init(const Key *key_, Value value_) {
+      key = key_;
+      new(_value) Value(std::move(value_));
+    }
+    Value release() {
+      Value value = std::move(*reinterpret_cast<Value*>(_value));
+      reinterpret_cast<Value*>(_value)->~Value();
+      return value;
+    }
+    const Value &value() {
+      return *reinterpret_cast<Value*>(_value);
+    }
+    Entry *prev;
+    Entry *next;
+    const Key *key;
+  private:
+    alignas(Value) char _value[sizeof(Value)];
+    DISALLOW_COPY_AND_ASSIGN(Entry);
+  };
+
+  void _removeFromQueue(const Entry &entry) {
+    entry.prev->next = entry.next;
+    entry.next->prev = entry.prev;
+  }
+
+  std::unordered_map<Key, Entry> _entries;
+  Entry _sentinel;
+
+  DISALLOW_COPY_AND_ASSIGN(QueueMap);
+};
+
+}
+}
+
+#endif
diff --git a/implementations/encrypted/EncryptedBlock.cpp b/implementations/encrypted/EncryptedBlock.cpp
index 59da307d..5f66d9c9 100644
--- a/implementations/encrypted/EncryptedBlock.cpp
+++ b/implementations/encrypted/EncryptedBlock.cpp
@@ -1,91 +1 @@
 #include "EncryptedBlock.h"
-#include <cryptopp/cryptopp/modes.h>
-
-#include "../../utils/BlockStoreUtils.h"
-
-using CryptoPP::CFB_Mode;
-using CryptoPP::AES;
-
-using std::make_unique;
-
-//TODO not only encryption, but also hmac
-
-namespace blockstore {
-namespace encrypted {
-
-constexpr unsigned int EncryptedBlock::IV_SIZE;
-
-std::unique_ptr<EncryptedBlock> EncryptedBlock::TryCreateNew(BlockStore *baseBlockStore, const Key &key, Data data, const EncryptionKey &encKey) {
-  Data encrypted = _encrypt(data, encKey);
-  auto baseBlock = baseBlockStore->tryCreate(key, std::move(encrypted));
-  if (baseBlock.get() == nullptr) {
-	//TODO Test this code branch
-	return nullptr;
-  }
-
-  return make_unique<EncryptedBlock>(std::move(baseBlock), encKey, std::move(data));
-}
-
-EncryptedBlock::EncryptedBlock(std::unique_ptr<Block> baseBlock, const EncryptionKey &encKey)
-    :EncryptedBlock(std::move(baseBlock), encKey, Data(USEABLE_BLOCK_SIZE(baseBlock->size()))) {
-  _decryptFromBaseBlock();
-}
-
-EncryptedBlock::EncryptedBlock(std::unique_ptr<Block> baseBlock, const EncryptionKey &encKey, Data plaintextData)
-    :Block(baseBlock->key()),
-	 _baseBlock(std::move(baseBlock)),
-	 _plaintextData(std::move(plaintextData)),
-	 _encKey(encKey),
-	 _dataChanged(false) {
-}
-
-EncryptedBlock::~EncryptedBlock() {
-  _encryptToBaseBlock();
-}
-
-const void *EncryptedBlock::data() const {
-  return _plaintextData.data();
-}
-
-void EncryptedBlock::write(const void *source, uint64_t offset, uint64_t size) {
-  assert(offset <= _plaintextData.size() && offset + size <= _plaintextData.size()); //Also check offset < _data->size() because of possible overflow in the addition
-  std::memcpy((uint8_t*)_plaintextData.data()+offset, source, size);
-  _dataChanged = true;
-}
-
-void EncryptedBlock::flush() {
-  _encryptToBaseBlock();
-  return _baseBlock->flush();
-}
-
-size_t EncryptedBlock::size() const {
-  return _plaintextData.size();
-}
-
-void EncryptedBlock::_decryptFromBaseBlock() {
-  const byte *iv = (byte*)_baseBlock->data();
-  const byte *data = (byte*)_baseBlock->data() + IV_SIZE;
-  auto decryption = CFB_Mode<AES>::Decryption((byte*)_encKey.data(), EncryptionKey::BINARY_LENGTH, iv);
-  decryption.ProcessData((byte*)_plaintextData.data(), data, _plaintextData.size());
-}
-
-void EncryptedBlock::_encryptToBaseBlock() {
-  if (_dataChanged) {
-	Data encrypted = _encrypt(_plaintextData, _encKey);
-    _baseBlock->write(encrypted.data(), 0, encrypted.size());
-    _dataChanged = false;
-  }
-}
-
-Data EncryptedBlock::_encrypt(const Data &plaintext, const EncryptionKey &encKey) {
-  FixedSizeData<IV_SIZE> iv = FixedSizeData<IV_SIZE>::CreateRandom();
-  auto encryption = CFB_Mode<AES>::Encryption(encKey.data(), EncryptionKey::BINARY_LENGTH, iv.data());
-  //TODO More performance when not using "Data encrypted" object, but encrypting directly to a target that was specified via a parameter using a specialized CryptoPP sink
-  Data encrypted(IV_SIZE + plaintext.size());
-  std::memcpy(encrypted.data(), iv.data(), IV_SIZE);
-  encryption.ProcessData((byte*)encrypted.data() + IV_SIZE, (byte*)plaintext.data(), plaintext.size());
-  return encrypted;
-}
-
-}
-}
diff --git a/implementations/encrypted/EncryptedBlock.h b/implementations/encrypted/EncryptedBlock.h
index 84b66019..f7b96f5b 100644
--- a/implementations/encrypted/EncryptedBlock.h
+++ b/implementations/encrypted/EncryptedBlock.h
@@ -3,59 +3,156 @@
 #define BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_ENCRYPTEDBLOCK_H_
 
 #include "../../interface/Block.h"
-#include "EncryptionKey.h"
-#include "../../utils/Data.h"
+#include <messmer/cpp-utils/data/Data.h>
 #include "../../interface/BlockStore.h"
 
 #include "messmer/cpp-utils/macros.h"
 #include <memory>
+#include <iostream>
+#include <boost/optional.hpp>
+#include "ciphers/Cipher.h"
 
 namespace blockstore {
 namespace encrypted {
-class EncryptedBlockStore;
+template<class Cipher> class EncryptedBlockStore;
 
+//TODO Test EncryptedBlock
+
+template<class Cipher>
 class EncryptedBlock: public Block {
 public:
+  BOOST_CONCEPT_ASSERT((CipherConcept<Cipher>));
+  static std::unique_ptr<EncryptedBlock> TryCreateNew(BlockStore *baseBlockStore, const Key &key, cpputils::Data data, const typename Cipher::EncryptionKey &encKey);
+  static std::unique_ptr<EncryptedBlock> TryDecrypt(std::unique_ptr<Block> baseBlock, const typename Cipher::EncryptionKey &key);
+
   //TODO Storing key twice (in parent class and in object pointed to). Once would be enough.
-  EncryptedBlock(std::unique_ptr<Block> baseBlock, const EncryptionKey &encKey);
-  EncryptedBlock(std::unique_ptr<Block> baseBlock, const EncryptionKey &encKey, Data plaintextData);
+  EncryptedBlock(std::unique_ptr<Block> baseBlock, const typename Cipher::EncryptionKey &key, cpputils::Data plaintextWithHeader);
   virtual ~EncryptedBlock();
 
-  static std::unique_ptr<EncryptedBlock> TryCreateNew(BlockStore *baseBlockStore, const Key &key, Data data, const EncryptionKey &encKey);
-
   const void *data() const override;
-  void write(const void *source, uint64_t offset, uint64_t size) override;
+  void write(const void *source, uint64_t offset, uint64_t count) override;
   void flush() override;
 
   size_t size() const override;
 
-  static constexpr unsigned int BASE_BLOCK_SIZE(unsigned int useableBlockSize) {
-    return useableBlockSize + IV_SIZE;
-  }
-
-  static constexpr unsigned int USEABLE_BLOCK_SIZE(unsigned int baseBlockSize) {
-    return baseBlockSize - IV_SIZE;
-  }
+  std::unique_ptr<Block> releaseBlock();
 
 private:
   std::unique_ptr<Block> _baseBlock;
-  Data _plaintextData;
-  EncryptionKey _encKey;
+  cpputils::Data _plaintextWithHeader;
+  typename Cipher::EncryptionKey _encKey;
   bool _dataChanged;
 
-  static constexpr unsigned int IV_SIZE = CryptoPP::AES::BLOCKSIZE;
-
-  byte *baseBlockIV();
-  byte *baseBlockData();
+  static constexpr unsigned int HEADER_LENGTH = Key::BINARY_LENGTH;
 
   void _encryptToBaseBlock();
-  void _decryptFromBaseBlock();
-
-  static Data _encrypt(const Data &plaintext, const EncryptionKey &encKey);
+  static cpputils::Data _prependKeyHeaderToData(const Key &key, cpputils::Data data);
+  static bool _keyHeaderIsCorrect(const Key &key, const cpputils::Data &data);
 
   DISALLOW_COPY_AND_ASSIGN(EncryptedBlock);
 };
 
+template<class Cipher>
+constexpr unsigned int EncryptedBlock<Cipher>::HEADER_LENGTH;
+
+
+template<class Cipher>
+std::unique_ptr<EncryptedBlock<Cipher>> EncryptedBlock<Cipher>::TryCreateNew(BlockStore *baseBlockStore, const Key &key, cpputils::Data data, const typename Cipher::EncryptionKey &encKey) {
+  cpputils::Data plaintextWithHeader = _prependKeyHeaderToData(key, std::move(data));
+  cpputils::Data encrypted = Cipher::encrypt((byte*)plaintextWithHeader.data(), plaintextWithHeader.size(), encKey);
+  auto baseBlock = baseBlockStore->tryCreate(key, std::move(encrypted));
+  if (baseBlock.get() == nullptr) {
+    //TODO Test this code branch
+    return nullptr;
+  }
+
+  return std::make_unique<EncryptedBlock>(std::move(baseBlock), encKey, std::move(plaintextWithHeader));
+}
+
+template<class Cipher>
+std::unique_ptr<EncryptedBlock<Cipher>> EncryptedBlock<Cipher>::TryDecrypt(std::unique_ptr<Block> baseBlock, const typename Cipher::EncryptionKey &encKey) {
+  //TODO Change BlockStore so we can read their "class Data" objects instead of "void *data()", and then we can change the Cipher interface to take Data objects instead of "byte *" + size
+  boost::optional<cpputils::Data> plaintextWithHeader = Cipher::decrypt((byte*)baseBlock->data(), baseBlock->size(), encKey);
+  if(!plaintextWithHeader) {
+    //Decryption failed (e.g. an authenticated cipher detected modifications to the ciphertext)
+    //TODO Think about logging
+    std::cerr << "Decrypting block " << baseBlock->key().ToString() << " failed. Was the block modified by an attacker?" << std::endl;
+    return nullptr;
+  }
+  if(!_keyHeaderIsCorrect(baseBlock->key(), *plaintextWithHeader)) {
+    //The stored key in the block data is incorrect - an attacker might have exchanged the contents with the encrypted data from a different block
+    //TODO Think about logging
+    std::cerr << "Decrypting block " << baseBlock->key().ToString() << " failed due to invalid block key. Was the block modified by an attacker?" << std::endl;
+    return nullptr;
+  }
+  return std::make_unique<EncryptedBlock<Cipher>>(std::move(baseBlock), encKey, std::move(*plaintextWithHeader));
+}
+
+template<class Cipher>
+cpputils::Data EncryptedBlock<Cipher>::_prependKeyHeaderToData(const Key &key, cpputils::Data data) {
+  static_assert(HEADER_LENGTH >= Key::BINARY_LENGTH, "Key doesn't fit into the header");
+  cpputils::Data result(data.size() + HEADER_LENGTH);
+  std::memcpy(result.data(), key.data(), Key::BINARY_LENGTH);
+  std::memcpy((uint8_t*)result.data() + Key::BINARY_LENGTH, data.data(), data.size());
+  return result;
+}
+
+template<class Cipher>
+bool EncryptedBlock<Cipher>::_keyHeaderIsCorrect(const Key &key, const cpputils::Data &data) {
+  return 0 == std::memcmp(key.data(), data.data(), Key::BINARY_LENGTH);
+}
+
+template<class Cipher>
+EncryptedBlock<Cipher>::EncryptedBlock(std::unique_ptr<Block> baseBlock, const typename Cipher::EncryptionKey &encKey, cpputils::Data plaintextWithHeader)
+    :Block(baseBlock->key()),
+   _baseBlock(std::move(baseBlock)),
+   _plaintextWithHeader(std::move(plaintextWithHeader)),
+   _encKey(encKey),
+   _dataChanged(false) {
+}
+
+template<class Cipher>
+EncryptedBlock<Cipher>::~EncryptedBlock() {
+  _encryptToBaseBlock();
+}
+
+template<class Cipher>
+const void *EncryptedBlock<Cipher>::data() const {
+  return (uint8_t*)_plaintextWithHeader.data() + HEADER_LENGTH;
+}
+
+template<class Cipher>
+void EncryptedBlock<Cipher>::write(const void *source, uint64_t offset, uint64_t count) {
+  assert(offset <= size() && offset + count <= size()); //Also check offset < size() because of possible overflow in the addition
+  std::memcpy((uint8_t*)_plaintextWithHeader.data()+HEADER_LENGTH+offset, source, count);
+  _dataChanged = true;
+}
+
+template<class Cipher>
+void EncryptedBlock<Cipher>::flush() {
+  _encryptToBaseBlock();
+  return _baseBlock->flush();
+}
+
+template<class Cipher>
+size_t EncryptedBlock<Cipher>::size() const {
+  return _plaintextWithHeader.size() - HEADER_LENGTH;
+}
+
+template<class Cipher>
+void EncryptedBlock<Cipher>::_encryptToBaseBlock() {
+  if (_dataChanged) {
+    cpputils::Data encrypted = Cipher::encrypt((byte*)_plaintextWithHeader.data(), _plaintextWithHeader.size(), _encKey);
+    _baseBlock->write(encrypted.data(), 0, encrypted.size());
+    _dataChanged = false;
+  }
+}
+
+template<class Cipher>
+std::unique_ptr<Block> EncryptedBlock<Cipher>::releaseBlock() {
+  return std::move(_baseBlock);
+}
+
 }
 }
 
diff --git a/implementations/encrypted/EncryptedBlockStore.cpp b/implementations/encrypted/EncryptedBlockStore.cpp
index 1eb88f42..5ab7ca32 100644
--- a/implementations/encrypted/EncryptedBlockStore.cpp
+++ b/implementations/encrypted/EncryptedBlockStore.cpp
@@ -1,42 +1 @@
 #include "EncryptedBlockStore.h"
-#include "EncryptedBlock.h"
-#include <messmer/cpp-utils/pointer.h>
-#include "../../utils/BlockStoreUtils.h"
-
-using std::unique_ptr;
-using std::make_unique;
-
-namespace blockstore {
-namespace encrypted {
-
-EncryptedBlockStore::EncryptedBlockStore(unique_ptr<BlockStore> baseBlockStore, const EncryptionKey &encKey)
- : _baseBlockStore(std::move(baseBlockStore)), _encKey(encKey) {
-}
-
-Key EncryptedBlockStore::createKey() {
-  return _baseBlockStore->createKey();
-}
-
-unique_ptr<Block> EncryptedBlockStore::tryCreate(const Key &key, Data data) {
-  return EncryptedBlock::TryCreateNew(_baseBlockStore.get(), key, std::move(data), _encKey);
-}
-
-unique_ptr<Block> EncryptedBlockStore::load(const Key &key) {
-  auto block = _baseBlockStore->load(key);
-  if (block.get() == nullptr) {
-    return nullptr;
-  }
-  return make_unique<EncryptedBlock>(std::move(block), _encKey);
-}
-
-void EncryptedBlockStore::remove(unique_ptr<Block> block) {
-  return _baseBlockStore->remove(std::move(block));
-}
-
-uint64_t EncryptedBlockStore::numBlocks() const {
-  return _baseBlockStore->numBlocks();
-}
-
-}
-}
-
diff --git a/implementations/encrypted/EncryptedBlockStore.h b/implementations/encrypted/EncryptedBlockStore.h
index 2e897d1d..ad7acd31 100644
--- a/implementations/encrypted/EncryptedBlockStore.h
+++ b/implementations/encrypted/EncryptedBlockStore.h
@@ -4,28 +4,79 @@
 
 #include "../../interface/BlockStore.h"
 #include <messmer/cpp-utils/macros.h>
-#include "EncryptionKey.h"
+#include <messmer/cpp-utils/pointer.h>
+#include "EncryptedBlock.h"
+#include <iostream>
 
 namespace blockstore {
 namespace encrypted {
 
+template<class Cipher>
 class EncryptedBlockStore: public BlockStore {
 public:
-  EncryptedBlockStore(std::unique_ptr<BlockStore> baseBlockStore, const EncryptionKey &encKey);
+  EncryptedBlockStore(std::unique_ptr<BlockStore> baseBlockStore, const typename Cipher::EncryptionKey &encKey);
 
+  //TODO Are createKey() tests included in generic BlockStoreTest? If not, add it!
   Key createKey() override;
-  std::unique_ptr<Block> tryCreate(const Key &key, Data data) override;
+  std::unique_ptr<Block> tryCreate(const Key &key, cpputils::Data data) override;
   std::unique_ptr<Block> load(const Key &key) override;
   void remove(std::unique_ptr<Block> block) override;
   uint64_t numBlocks() const override;
 
+  //This function should only be used by test cases
+  void __setKey(const typename Cipher::EncryptionKey &encKey);
+
 private:
   std::unique_ptr<BlockStore> _baseBlockStore;
-  EncryptionKey _encKey;
+  typename Cipher::EncryptionKey _encKey;
 
   DISALLOW_COPY_AND_ASSIGN(EncryptedBlockStore);
 };
 
+
+
+template<class Cipher>
+EncryptedBlockStore<Cipher>::EncryptedBlockStore(std::unique_ptr<BlockStore> baseBlockStore, const typename Cipher::EncryptionKey &encKey)
+ : _baseBlockStore(std::move(baseBlockStore)), _encKey(encKey) {
+}
+
+template<class Cipher>
+Key EncryptedBlockStore<Cipher>::createKey() {
+  return _baseBlockStore->createKey();
+}
+
+template<class Cipher>
+std::unique_ptr<Block> EncryptedBlockStore<Cipher>::tryCreate(const Key &key, cpputils::Data data) {
+  //TODO Test that this returns nullptr when base blockstore returns nullptr  (for all pass-through-blockstores)
+  return EncryptedBlock<Cipher>::TryCreateNew(_baseBlockStore.get(), key, std::move(data), _encKey);
+}
+
+template<class Cipher>
+std::unique_ptr<Block> EncryptedBlockStore<Cipher>::load(const Key &key) {
+  auto block = _baseBlockStore->load(key);
+  if (block.get() == nullptr) {
+    //TODO Test this path (for all pass-through-blockstores)
+    return nullptr;
+  }
+  return EncryptedBlock<Cipher>::TryDecrypt(std::move(block), _encKey);
+}
+
+template<class Cipher>
+void EncryptedBlockStore<Cipher>::remove(std::unique_ptr<Block> block) {
+  auto baseBlock = cpputils::dynamic_pointer_move<EncryptedBlock<Cipher>>(block)->releaseBlock();
+  return _baseBlockStore->remove(std::move(baseBlock));
+}
+
+template<class Cipher>
+uint64_t EncryptedBlockStore<Cipher>::numBlocks() const {
+  return _baseBlockStore->numBlocks();
+}
+
+template<class Cipher>
+void EncryptedBlockStore<Cipher>::__setKey(const typename Cipher::EncryptionKey &encKey) {
+  _encKey = encKey;
+}
+
 }
 }
 
diff --git a/implementations/encrypted/EncryptionKey.cpp b/implementations/encrypted/EncryptionKey.cpp
deleted file mode 100644
index 18a97b45..00000000
--- a/implementations/encrypted/EncryptionKey.cpp
+++ /dev/null
@@ -1 +0,0 @@
-#include "EncryptionKey.h"
diff --git a/implementations/encrypted/EncryptionKey.h b/implementations/encrypted/EncryptionKey.h
deleted file mode 100644
index 408d30b8..00000000
--- a/implementations/encrypted/EncryptionKey.h
+++ /dev/null
@@ -1,16 +0,0 @@
-#pragma once
-#ifndef MESSMER_BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_ENCRYPTIONKEY_H_
-#define MESSMER_BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_ENCRYPTIONKEY_H_
-
-#include "../../utils/FixedSizeData.h"
-
-namespace blockstore {
-namespace encrypted {
-
-//TODO Does EncryptionKey::GenerateRandom() use a PseudoRandomGenerator? Would be better to use real randomness.
-using EncryptionKey = FixedSizeData<CryptoPP::AES::MAX_KEYLENGTH>;
-
-}
-}
-
-#endif
diff --git a/implementations/encrypted/ciphers/AES256_CFB.cpp b/implementations/encrypted/ciphers/AES256_CFB.cpp
new file mode 100644
index 00000000..c7737b1b
--- /dev/null
+++ b/implementations/encrypted/ciphers/AES256_CFB.cpp
@@ -0,0 +1,37 @@
+#include <cryptopp/cryptopp/modes.h>
+#include "AES256_CFB.h"
+
+using CryptoPP::CFB_Mode;
+using CryptoPP::AES;
+using cpputils::Data;
+using cpputils::FixedSizeData;
+
+namespace blockstore {
+namespace encrypted {
+
+constexpr unsigned int AES256_CFB::IV_SIZE;
+
+Data AES256_CFB::encrypt(const byte *plaintext, unsigned int plaintextSize, const EncryptionKey &encKey) {
+  FixedSizeData<IV_SIZE> iv = FixedSizeData<IV_SIZE>::CreateRandom();
+  auto encryption = CFB_Mode<AES>::Encryption(encKey.data(), encKey.BINARY_LENGTH, iv.data());
+  Data ciphertext(ciphertextSize(plaintextSize));
+  std::memcpy(ciphertext.data(), iv.data(), IV_SIZE);
+  encryption.ProcessData((byte*)ciphertext.data() + IV_SIZE, plaintext, plaintextSize);
+  return ciphertext;
+}
+
+boost::optional<Data> AES256_CFB::decrypt(const byte *ciphertext, unsigned int ciphertextSize, const EncryptionKey &encKey) {
+  if (ciphertextSize < IV_SIZE) {
+    return boost::none;
+  }
+
+  const byte *ciphertextIV = ciphertext;
+  const byte *ciphertextData = ciphertext + IV_SIZE;
+  auto decryption = CFB_Mode<AES>::Decryption((byte*)encKey.data(), encKey.BINARY_LENGTH, ciphertextIV);
+  Data plaintext(plaintextSize(ciphertextSize));
+  decryption.ProcessData((byte*)plaintext.data(), ciphertextData, plaintext.size());
+  return std::move(plaintext);
+}
+
+}
+}
diff --git a/implementations/encrypted/ciphers/AES256_CFB.h b/implementations/encrypted/ciphers/AES256_CFB.h
new file mode 100644
index 00000000..313842d6
--- /dev/null
+++ b/implementations/encrypted/ciphers/AES256_CFB.h
@@ -0,0 +1,39 @@
+#pragma once
+#ifndef MESSMER_BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_CIPHERS_AES256_CFB_H_
+#define MESSMER_BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_CIPHERS_AES256_CFB_H_
+
+#include <messmer/cpp-utils/data/FixedSizeData.h>
+#include <messmer/cpp-utils/data/Data.h>
+#include <cryptopp/cryptopp/aes.h>
+#include <boost/optional.hpp>
+#include "Cipher.h"
+
+namespace blockstore {
+namespace encrypted {
+
+class AES256_CFB {
+public:
+  BOOST_CONCEPT_ASSERT((CipherConcept<AES256_CFB>));
+
+  using EncryptionKey = cpputils::FixedSizeData<32>;
+  static_assert(32 == CryptoPP::AES::MAX_KEYLENGTH, "If AES offered larger keys, we should offer a variant with it");
+
+  static constexpr unsigned int ciphertextSize(unsigned int plaintextBlockSize) {
+    return plaintextBlockSize + IV_SIZE;
+  }
+
+  static constexpr unsigned int plaintextSize(unsigned int ciphertextBlockSize) {
+    return ciphertextBlockSize - IV_SIZE;
+  }
+
+  static cpputils::Data encrypt(const byte *plaintext, unsigned int plaintextSize, const EncryptionKey &encKey);
+  static boost::optional<cpputils::Data> decrypt(const byte *ciphertext, unsigned int ciphertextSize, const EncryptionKey &encKey);
+
+private:
+  static constexpr unsigned int IV_SIZE = CryptoPP::AES::BLOCKSIZE;
+};
+
+}
+}
+
+#endif
diff --git a/implementations/encrypted/ciphers/AES256_GCM.cpp b/implementations/encrypted/ciphers/AES256_GCM.cpp
new file mode 100644
index 00000000..4ccf400a
--- /dev/null
+++ b/implementations/encrypted/ciphers/AES256_GCM.cpp
@@ -0,0 +1,61 @@
+#include <cryptopp/cryptopp/gcm.h>
+#include "AES256_GCM.h"
+
+using CryptoPP::GCM;
+using CryptoPP::AES;
+using CryptoPP::AuthenticatedEncryptionFilter;
+using CryptoPP::AuthenticatedDecryptionFilter;
+using CryptoPP::ArraySource;
+using CryptoPP::ArraySink;
+using CryptoPP::GCM_64K_Tables;
+using CryptoPP::HashVerificationFilter;
+using cpputils::Data;
+using cpputils::FixedSizeData;
+
+namespace blockstore {
+namespace encrypted {
+
+constexpr unsigned int AES256_GCM::IV_SIZE;
+
+Data AES256_GCM::encrypt(const byte *plaintext, unsigned int plaintextSize, const EncryptionKey &encKey) {
+  FixedSizeData<IV_SIZE> iv = FixedSizeData<IV_SIZE>::CreateRandom();
+  GCM<AES, GCM_64K_Tables>::Encryption encryption;
+  encryption.SetKeyWithIV(encKey.data(), encKey.BINARY_LENGTH, iv.data(), IV_SIZE);
+  Data ciphertext(ciphertextSize(plaintextSize));
+
+  std::memcpy(ciphertext.data(), iv.data(), IV_SIZE);
+  ArraySource(plaintext, plaintextSize, true,
+    new AuthenticatedEncryptionFilter(encryption,
+      new ArraySink((byte*)ciphertext.data() + IV_SIZE, ciphertext.size() - IV_SIZE),
+      false, TAG_SIZE
+    )
+  );
+  return ciphertext;
+}
+
+boost::optional<Data> AES256_GCM::decrypt(const byte *ciphertext, unsigned int ciphertextSize, const EncryptionKey &encKey) {
+  if (ciphertextSize < IV_SIZE + TAG_SIZE) {
+    return boost::none;
+  }
+
+  const byte *ciphertextIV = ciphertext;
+  const byte *ciphertextData = ciphertext + IV_SIZE;
+  GCM<AES, GCM_64K_Tables>::Decryption decryption;
+  decryption.SetKeyWithIV((byte*)encKey.data(), encKey.BINARY_LENGTH, ciphertextIV, IV_SIZE);
+  Data plaintext(plaintextSize(ciphertextSize));
+
+  try {
+    ArraySource((byte*)ciphertextData, ciphertextSize - IV_SIZE, true,
+      new AuthenticatedDecryptionFilter(decryption,
+        new ArraySink((byte*)plaintext.data(), plaintext.size()),
+        AuthenticatedDecryptionFilter::DEFAULT_FLAGS, TAG_SIZE
+      )
+    );
+    return std::move(plaintext);
+  } catch (const HashVerificationFilter::HashVerificationFailed &e) {
+    return boost::none;
+  }
+}
+
+}
+}
diff --git a/implementations/encrypted/ciphers/AES256_GCM.h b/implementations/encrypted/ciphers/AES256_GCM.h
new file mode 100644
index 00000000..014ef1f0
--- /dev/null
+++ b/implementations/encrypted/ciphers/AES256_GCM.h
@@ -0,0 +1,39 @@
+#pragma once
+#ifndef MESSMER_BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_CIPHERS_AES256_GCM_H_
+#define MESSMER_BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_CIPHERS_AES256_GCM_H_
+
+#include <messmer/cpp-utils/data/FixedSizeData.h>
+#include <messmer/cpp-utils/data/Data.h>
+#include <cryptopp/cryptopp/aes.h>
+#include "Cipher.h"
+
+namespace blockstore {
+namespace encrypted {
+
+class AES256_GCM {
+public:
+  BOOST_CONCEPT_ASSERT((CipherConcept<AES256_GCM>));
+
+  using EncryptionKey = cpputils::FixedSizeData<32>;
+  static_assert(32 == CryptoPP::AES::MAX_KEYLENGTH, "If AES offered larger keys, we should offer a variant with it");
+
+  static constexpr unsigned int ciphertextSize(unsigned int plaintextBlockSize) {
+    return plaintextBlockSize + IV_SIZE + TAG_SIZE;
+  }
+
+  static constexpr unsigned int plaintextSize(unsigned int ciphertextBlockSize) {
+    return ciphertextBlockSize - IV_SIZE - TAG_SIZE;
+  }
+
+  static cpputils::Data encrypt(const byte *plaintext, unsigned int plaintextSize, const EncryptionKey &encKey);
+  static boost::optional<cpputils::Data> decrypt(const byte *ciphertext, unsigned int ciphertextSize, const EncryptionKey &encKey);
+
+private:
+  static constexpr unsigned int IV_SIZE = CryptoPP::AES::BLOCKSIZE;
+  static constexpr unsigned int TAG_SIZE = 16;
+};
+
+}
+}
+
+#endif
diff --git a/implementations/encrypted/ciphers/Cipher.h b/implementations/encrypted/ciphers/Cipher.h
new file mode 100644
index 00000000..5195bcb4
--- /dev/null
+++ b/implementations/encrypted/ciphers/Cipher.h
@@ -0,0 +1,33 @@
+#pragma once
+#ifndef MESSMER_BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_CIPHERS_CIPHER_H_
+#define MESSMER_BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_CIPHERS_CIPHER_H_
+
+#include <boost/concept_check.hpp>
+#include <cstdint>
+#include <messmer/cpp-utils/data/Data.h>
+
+namespace blockstore {
+namespace encrypted {
+
+template<class X>
+struct CipherConcept {
+public:
+  BOOST_CONCEPT_USAGE(CipherConcept) {
+    same_type(UINT32_C(0), X::ciphertextSize(UINT32_C(5)));
+    same_type(UINT32_C(0), X::plaintextSize(UINT32_C(5)));
+    typename X::EncryptionKey key = X::EncryptionKey::CreateRandom();
+    same_type(cpputils::Data(0), X::encrypt((uint8_t*)nullptr, UINT32_C(0), key));
+    same_type(boost::optional<cpputils::Data>(cpputils::Data(0)), X::decrypt((uint8_t*)nullptr, UINT32_C(0), key));
+  }
+
+private:
+  // Type deduction will fail unless the arguments have the same type.
+  template <typename T> void same_type(T const&, T const&);
+};
+
+}
+}
+
+
+
+#endif
diff --git a/implementations/inmemory/InMemoryBlock.cpp b/implementations/inmemory/InMemoryBlock.cpp
index 69d8a142..14d27df9 100644
--- a/implementations/inmemory/InMemoryBlock.cpp
+++ b/implementations/inmemory/InMemoryBlock.cpp
@@ -9,6 +9,7 @@ using std::ostream;
 using std::ifstream;
 using std::ofstream;
 using std::ios;
+using cpputils::Data;
 
 namespace blockstore {
 namespace inmemory {
diff --git a/implementations/inmemory/InMemoryBlock.h b/implementations/inmemory/InMemoryBlock.h
index 4efb1553..bab8427c 100644
--- a/implementations/inmemory/InMemoryBlock.h
+++ b/implementations/inmemory/InMemoryBlock.h
@@ -3,7 +3,7 @@
 #define BLOCKSTORE_IMPLEMENTATIONS_INMEMORY_INMEMORYBLOCK_H_
 
 #include "../../interface/Block.h"
-#include "../../utils/Data.h"
+#include <messmer/cpp-utils/data/Data.h>
 
 namespace blockstore {
 namespace inmemory {
@@ -11,7 +11,7 @@ class InMemoryBlockStore;
 
 class InMemoryBlock: public Block {
 public:
-  InMemoryBlock(const Key &key, Data size);
+  InMemoryBlock(const Key &key, cpputils::Data size);
   InMemoryBlock(const InMemoryBlock &rhs);
   virtual ~InMemoryBlock();
 
@@ -23,7 +23,7 @@ public:
   size_t size() const override;
 
 private:
-  std::shared_ptr<Data> _data;
+  std::shared_ptr<cpputils::Data> _data;
 };
 
 }
diff --git a/implementations/inmemory/InMemoryBlockStore.cpp b/implementations/inmemory/InMemoryBlockStore.cpp
index 3692b965..b4446349 100644
--- a/implementations/inmemory/InMemoryBlockStore.cpp
+++ b/implementations/inmemory/InMemoryBlockStore.cpp
@@ -9,6 +9,7 @@ using std::mutex;
 using std::lock_guard;
 using std::piecewise_construct;
 using std::make_tuple;
+using cpputils::Data;
 
 namespace blockstore {
 namespace inmemory {
diff --git a/implementations/inmemory/InMemoryBlockStore.h b/implementations/inmemory/InMemoryBlockStore.h
index 3faea85f..b9ec5d25 100644
--- a/implementations/inmemory/InMemoryBlockStore.h
+++ b/implementations/inmemory/InMemoryBlockStore.h
@@ -16,7 +16,7 @@ class InMemoryBlockStore: public BlockStoreWithRandomKeys {
 public:
   InMemoryBlockStore();
 
-  std::unique_ptr<Block> tryCreate(const Key &key, Data data) override;
+  std::unique_ptr<Block> tryCreate(const Key &key, cpputils::Data data) override;
   std::unique_ptr<Block> load(const Key &key) override;
   void remove(std::unique_ptr<Block> block) override;
   uint64_t numBlocks() const override;
diff --git a/implementations/ondisk/FileAlreadyExistsException.cpp b/implementations/ondisk/FileAlreadyExistsException.cpp
deleted file mode 100644
index 904b138c..00000000
--- a/implementations/ondisk/FileAlreadyExistsException.cpp
+++ /dev/null
@@ -1,19 +0,0 @@
-#include "FileAlreadyExistsException.h"
-
-namespace bf = boost::filesystem;
-
-using std::runtime_error;
-using std::string;
-
-namespace blockstore {
-namespace ondisk {
-
-FileAlreadyExistsException::FileAlreadyExistsException(const bf::path &filepath)
-: runtime_error(string("The file ")+filepath.c_str()+" already exists") {
-}
-
-FileAlreadyExistsException::~FileAlreadyExistsException() {
-}
-
-}
-}
diff --git a/implementations/ondisk/FileAlreadyExistsException.h b/implementations/ondisk/FileAlreadyExistsException.h
deleted file mode 100644
index 2a23fdd1..00000000
--- a/implementations/ondisk/FileAlreadyExistsException.h
+++ /dev/null
@@ -1,21 +0,0 @@
-#pragma once
-#ifndef BLOCKSTORE_IMPLEMENTATIONS_ONDISK_FILEALREADYEXISTSEXCEPTION_H_
-#define BLOCKSTORE_IMPLEMENTATIONS_ONDISK_FILEALREADYEXISTSEXCEPTION_H_
-
-#include <boost/filesystem/path.hpp>
-
-#include <stdexcept>
-
-namespace blockstore {
-namespace ondisk {
-
-class FileAlreadyExistsException: public std::runtime_error {
-public:
-  FileAlreadyExistsException(const boost::filesystem::path &filepath);
-  virtual ~FileAlreadyExistsException();
-};
-
-}
-}
-
-#endif
diff --git a/implementations/ondisk/OnDiskBlock.cpp b/implementations/ondisk/OnDiskBlock.cpp
index 4c0f25ef..4139a999 100644
--- a/implementations/ondisk/OnDiskBlock.cpp
+++ b/implementations/ondisk/OnDiskBlock.cpp
@@ -1,7 +1,6 @@
 #include <cstring>
 #include <fstream>
 #include <boost/filesystem.hpp>
-#include "FileAlreadyExistsException.h"
 #include "OnDiskBlock.h"
 #include "OnDiskBlockStore.h"
 #include "../../utils/FileDoesntExistException.h"
@@ -13,6 +12,7 @@ using std::ostream;
 using std::ifstream;
 using std::ofstream;
 using std::ios;
+using cpputils::Data;
 
 namespace bf = boost::filesystem;
 
@@ -47,11 +47,15 @@ unique_ptr<OnDiskBlock> OnDiskBlock::LoadFromDisk(const bf::path &rootdir, const
     //If it isn't a file, Data::LoadFromFile() would usually also crash. We still need this extra check
     //upfront, because Data::LoadFromFile() doesn't crash if we give it the path of a directory
     //instead the path of a file.
+    //TODO Data::LoadFromFile now returns boost::optional. Do we then still need this?
     if(!bf::is_regular_file(filepath)) {
       return nullptr;
     }
-    Data data = Data::LoadFromFile(filepath);
-    return unique_ptr<OnDiskBlock>(new OnDiskBlock(key, filepath, std::move(data)));
+    boost::optional<Data> data = Data::LoadFromFile(filepath);
+    if (!data) {
+      return nullptr;
+    }
+    return unique_ptr<OnDiskBlock>(new OnDiskBlock(key, filepath, std::move(*data)));
   } catch (const FileDoesntExistException &e) {
     return nullptr;
   }
diff --git a/implementations/ondisk/OnDiskBlock.h b/implementations/ondisk/OnDiskBlock.h
index a139249a..3acea481 100644
--- a/implementations/ondisk/OnDiskBlock.h
+++ b/implementations/ondisk/OnDiskBlock.h
@@ -4,7 +4,7 @@
 
 #include <boost/filesystem/path.hpp>
 #include "../../interface/Block.h"
-#include "../../utils/Data.h"
+#include <messmer/cpp-utils/data/Data.h>
 #include <iostream>
 
 #include "messmer/cpp-utils/macros.h"
@@ -18,7 +18,7 @@ public:
   virtual ~OnDiskBlock();
 
   static std::unique_ptr<OnDiskBlock> LoadFromDisk(const boost::filesystem::path &rootdir, const Key &key);
-  static std::unique_ptr<OnDiskBlock> CreateOnDisk(const boost::filesystem::path &rootdir, const Key &key, Data data);
+  static std::unique_ptr<OnDiskBlock> CreateOnDisk(const boost::filesystem::path &rootdir, const Key &key, cpputils::Data data);
   static void RemoveFromDisk(const boost::filesystem::path &rootdir, const Key &key);
 
   const void *data() const override;
@@ -30,10 +30,10 @@ public:
 
 private:
   const boost::filesystem::path _filepath;
-  Data _data;
+  cpputils::Data _data;
   bool _dataChanged;
 
-  OnDiskBlock(const Key &key, const boost::filesystem::path &filepath, Data data);
+  OnDiskBlock(const Key &key, const boost::filesystem::path &filepath, cpputils::Data data);
 
   void _fillDataWithZeroes();
   void _storeToDisk() const;
diff --git a/implementations/ondisk/OnDiskBlockStore.cpp b/implementations/ondisk/OnDiskBlockStore.cpp
index 4757807b..3335a047 100644
--- a/implementations/ondisk/OnDiskBlockStore.cpp
+++ b/implementations/ondisk/OnDiskBlockStore.cpp
@@ -4,6 +4,7 @@
 using std::unique_ptr;
 using std::make_unique;
 using std::string;
+using cpputils::Data;
 
 namespace bf = boost::filesystem;
 
diff --git a/implementations/ondisk/OnDiskBlockStore.h b/implementations/ondisk/OnDiskBlockStore.h
index 3a668d4d..af7f72fc 100644
--- a/implementations/ondisk/OnDiskBlockStore.h
+++ b/implementations/ondisk/OnDiskBlockStore.h
@@ -12,9 +12,9 @@ namespace ondisk {
 
 class OnDiskBlockStore: public BlockStoreWithRandomKeys {
 public:
-  OnDiskBlockStore(const boost::filesystem::path &rootdir);
+  explicit OnDiskBlockStore(const boost::filesystem::path &rootdir);
 
-  std::unique_ptr<Block> tryCreate(const Key &key, Data data) override;
+  std::unique_ptr<Block> tryCreate(const Key &key, cpputils::Data data) override;
   std::unique_ptr<Block> load(const Key &key) override;
   void remove(std::unique_ptr<Block> block) override;
   uint64_t numBlocks() const override;
diff --git a/implementations/parallelaccess/BlockRef.h b/implementations/parallelaccess/BlockRef.h
index a379ef7f..588b3c6e 100644
--- a/implementations/parallelaccess/BlockRef.h
+++ b/implementations/parallelaccess/BlockRef.h
@@ -14,7 +14,7 @@ class ParallelAccessBlockStore;
 class BlockRef: public Block, public parallelaccessstore::ParallelAccessStore<Block, BlockRef, Key>::ResourceRefBase {
 public:
   //TODO Unneccessarily storing Key twice here (in parent class and in _baseBlock).
-  BlockRef(Block *baseBlock): Block(baseBlock->key()), _baseBlock(baseBlock) {}
+  explicit BlockRef(Block *baseBlock): Block(baseBlock->key()), _baseBlock(baseBlock) {}
 
   const void *data() const override {
 	return _baseBlock->data();
diff --git a/implementations/parallelaccess/ParallelAccessBlockStore.cpp b/implementations/parallelaccess/ParallelAccessBlockStore.cpp
index 2f59bb79..19fdb343 100644
--- a/implementations/parallelaccess/ParallelAccessBlockStore.cpp
+++ b/implementations/parallelaccess/ParallelAccessBlockStore.cpp
@@ -24,7 +24,7 @@ Key ParallelAccessBlockStore::createKey() {
   return _baseBlockStore->createKey();
 }
 
-unique_ptr<Block> ParallelAccessBlockStore::tryCreate(const Key &key, Data data) {
+unique_ptr<Block> ParallelAccessBlockStore::tryCreate(const Key &key, cpputils::Data data) {
   auto block = _baseBlockStore->tryCreate(key, std::move(data));
   if (block.get() == nullptr) {
 	//TODO Test this code branch
diff --git a/implementations/parallelaccess/ParallelAccessBlockStore.h b/implementations/parallelaccess/ParallelAccessBlockStore.h
index 7c7c7adf..2f896b09 100644
--- a/implementations/parallelaccess/ParallelAccessBlockStore.h
+++ b/implementations/parallelaccess/ParallelAccessBlockStore.h
@@ -12,10 +12,10 @@ namespace parallelaccess {
 //TODO Check that this blockstore allows parallel destructing of blocks (otherwise we won't encrypt blocks in parallel)
 class ParallelAccessBlockStore: public BlockStore {
 public:
-  ParallelAccessBlockStore(std::unique_ptr<BlockStore> baseBlockStore);
+  explicit ParallelAccessBlockStore(std::unique_ptr<BlockStore> baseBlockStore);
 
   Key createKey() override;
-  std::unique_ptr<Block> tryCreate(const Key &key, Data data) override;
+  std::unique_ptr<Block> tryCreate(const Key &key, cpputils::Data data) override;
   std::unique_ptr<Block> load(const Key &key) override;
   void remove(std::unique_ptr<Block> block) override;
   uint64_t numBlocks() const override;
diff --git a/implementations/parallelaccess/ParallelAccessBlockStoreAdapter.h b/implementations/parallelaccess/ParallelAccessBlockStoreAdapter.h
index 56c9d7de..d4784f16 100644
--- a/implementations/parallelaccess/ParallelAccessBlockStoreAdapter.h
+++ b/implementations/parallelaccess/ParallelAccessBlockStoreAdapter.h
@@ -10,7 +10,7 @@ namespace parallelaccess {
 
 class ParallelAccessBlockStoreAdapter: public parallelaccessstore::ParallelAccessBaseStore<Block, Key> {
 public:
-  ParallelAccessBlockStoreAdapter(BlockStore *baseBlockStore)
+  explicit ParallelAccessBlockStoreAdapter(BlockStore *baseBlockStore)
     :_baseBlockStore(std::move(baseBlockStore)) {
   }
 
diff --git a/implementations/testfake/FakeBlock.cpp b/implementations/testfake/FakeBlock.cpp
index adf8bcdf..b6505aa7 100644
--- a/implementations/testfake/FakeBlock.cpp
+++ b/implementations/testfake/FakeBlock.cpp
@@ -10,6 +10,7 @@ using std::ifstream;
 using std::ofstream;
 using std::ios;
 using std::string;
+using cpputils::Data;
 
 namespace blockstore {
 namespace testfake {
diff --git a/implementations/testfake/FakeBlock.h b/implementations/testfake/FakeBlock.h
index 7f49f224..a0fc5c41 100644
--- a/implementations/testfake/FakeBlock.h
+++ b/implementations/testfake/FakeBlock.h
@@ -3,7 +3,7 @@
 #define BLOCKSTORE_IMPLEMENTATIONS_INMEMORY_INMEMORYBLOCK_H_
 
 #include "../../interface/Block.h"
-#include "../../utils/Data.h"
+#include <messmer/cpp-utils/data/Data.h>
 
 #include "messmer/cpp-utils/macros.h"
 
@@ -13,7 +13,7 @@ class FakeBlockStore;
 
 class FakeBlock: public Block {
 public:
-  FakeBlock(FakeBlockStore *store, const Key &key, std::shared_ptr<Data> data, bool dirty);
+  FakeBlock(FakeBlockStore *store, const Key &key, std::shared_ptr<cpputils::Data> data, bool dirty);
   virtual ~FakeBlock();
 
   const void *data() const override;
@@ -25,7 +25,7 @@ public:
 
 private:
   FakeBlockStore *_store;
-  std::shared_ptr<Data> _data;
+  std::shared_ptr<cpputils::Data> _data;
   bool _dataChanged;
 
   DISALLOW_COPY_AND_ASSIGN(FakeBlock);
diff --git a/implementations/testfake/FakeBlockStore.cpp b/implementations/testfake/FakeBlockStore.cpp
index 50dce405..eb1e09f4 100644
--- a/implementations/testfake/FakeBlockStore.cpp
+++ b/implementations/testfake/FakeBlockStore.cpp
@@ -7,6 +7,7 @@ using std::make_shared;
 using std::string;
 using std::mutex;
 using std::lock_guard;
+using cpputils::Data;
 
 namespace blockstore {
 namespace testfake {
diff --git a/implementations/testfake/FakeBlockStore.h b/implementations/testfake/FakeBlockStore.h
index cec32b56..9d291cec 100644
--- a/implementations/testfake/FakeBlockStore.h
+++ b/implementations/testfake/FakeBlockStore.h
@@ -3,7 +3,7 @@
 #define BLOCKSTORE_IMPLEMENTATIONS_INMEMORY_INMEMORYBLOCKSTORE_H_
 
 #include "../../interface/helpers/BlockStoreWithRandomKeys.h"
-#include "../../utils/Data.h"
+#include <messmer/cpp-utils/data/Data.h>
 #include "messmer/cpp-utils/macros.h"
 
 #include <mutex>
@@ -31,24 +31,24 @@ class FakeBlockStore: public BlockStoreWithRandomKeys {
 public:
   FakeBlockStore();
 
-  std::unique_ptr<Block> tryCreate(const Key &key, Data data) override;
+  std::unique_ptr<Block> tryCreate(const Key &key, cpputils::Data data) override;
   std::unique_ptr<Block> load(const Key &key) override;
   void remove(std::unique_ptr<Block> block) override;
   uint64_t numBlocks() const override;
 
-  void updateData(const Key &key, const Data &data);
+  void updateData(const Key &key, const cpputils::Data &data);
 
 private:
-  std::map<std::string, Data> _blocks;
+  std::map<std::string, cpputils::Data> _blocks;
 
   //This vector keeps a handle of the data regions for all created FakeBlock objects.
   //This way, it is ensured that no two created FakeBlock objects will work on the
   //same data region. Without this, it could happen that a test case creates a FakeBlock,
   //destructs it, creates another one, and the new one gets the same memory region.
   //We want to avoid this for the reasons mentioned above (overflow data).
-  std::vector<std::shared_ptr<Data>> _used_dataregions_for_blocks;
+  std::vector<std::shared_ptr<cpputils::Data>> _used_dataregions_for_blocks;
 
-  std::unique_ptr<Block> makeFakeBlockFromData(const Key &key, const Data &data, bool dirty);
+  std::unique_ptr<Block> makeFakeBlockFromData(const Key &key, const cpputils::Data &data, bool dirty);
 
   DISALLOW_COPY_AND_ASSIGN(FakeBlockStore);
 };
diff --git a/interface/BlockStore.h b/interface/BlockStore.h
index 8ea14ed3..9bb9b14e 100644
--- a/interface/BlockStore.h
+++ b/interface/BlockStore.h
@@ -5,7 +5,7 @@
 #include "Block.h"
 #include <string>
 #include <memory>
-#include "../utils/Data.h"
+#include <messmer/cpp-utils/data/Data.h>
 
 namespace blockstore {
 
@@ -15,20 +15,20 @@ public:
 
   virtual Key createKey() = 0;
   //Returns nullptr if key already exists
-  virtual std::unique_ptr<Block> tryCreate(const Key &key, Data data) = 0;
+  virtual std::unique_ptr<Block> tryCreate(const Key &key, cpputils::Data data) = 0;
   //TODO Use boost::optional (if key doesn't exist)
   // Return nullptr if block with this key doesn't exists
   virtual std::unique_ptr<Block> load(const Key &key) = 0;
   virtual void remove(std::unique_ptr<Block> block) = 0;
   virtual uint64_t numBlocks() const = 0;
 
-  std::unique_ptr<Block> create(const Data &data) {
-	std::unique_ptr<Block> block(nullptr);
-	while(block.get() == nullptr) {
-	  //TODO Copy necessary?
-	  block = tryCreate(createKey(), data.copy());
-	}
-	return block;
+  std::unique_ptr<Block> create(const cpputils::Data &data) {
+    std::unique_ptr<Block> block(nullptr);
+    while(block.get() == nullptr) {
+      //TODO Copy necessary?
+      block = tryCreate(createKey(), data.copy());
+    }
+    return block;
   }
 };
 
diff --git a/test/implementations/caching/cache/CacheTest_MoveConstructor.cpp b/test/implementations/caching/cache/CacheTest_MoveConstructor.cpp
new file mode 100644
index 00000000..5efba4a8
--- /dev/null
+++ b/test/implementations/caching/cache/CacheTest_MoveConstructor.cpp
@@ -0,0 +1,36 @@
+#include <google/gtest/gtest.h>
+#include <memory>
+#include "../../../../implementations/caching/cache/Cache.h"
+#include "testutils/MinimalKeyType.h"
+#include "testutils/CopyableMovableValueType.h"
+
+using namespace blockstore::caching;
+
+using ::testing::Test;
+using std::unique_ptr;
+using std::make_unique;
+
+//Test that Cache uses a move constructor for Value if possible
+class CacheTest_MoveConstructor: public Test {
+public:
+  CacheTest_MoveConstructor() {
+    CopyableMovableValueType::numCopyConstructorCalled = 0;
+    cache = make_unique<Cache<MinimalKeyType, CopyableMovableValueType>>();
+  }
+  unique_ptr<Cache<MinimalKeyType, CopyableMovableValueType>> cache;
+};
+
+TEST_F(CacheTest_MoveConstructor, MoveIntoCache) {
+  cache->push(MinimalKeyType::create(0), CopyableMovableValueType(2));
+  CopyableMovableValueType val = cache->pop(MinimalKeyType::create(0)).value();
+  val.value(); //Access it to avoid the compiler optimizing the assignment away
+  EXPECT_EQ(0, CopyableMovableValueType::numCopyConstructorCalled);
+}
+
+TEST_F(CacheTest_MoveConstructor, CopyIntoCache) {
+  CopyableMovableValueType value(2);
+  cache->push(MinimalKeyType::create(0), value);
+  CopyableMovableValueType val = cache->pop(MinimalKeyType::create(0)).value();
+  val.value(); //Access it to avoid the compiler optimizing the assignment away
+  EXPECT_EQ(1, CopyableMovableValueType::numCopyConstructorCalled);
+}
diff --git a/test/implementations/caching/cache/CacheTest_PushAndPop.cpp b/test/implementations/caching/cache/CacheTest_PushAndPop.cpp
new file mode 100644
index 00000000..c64cc7b9
--- /dev/null
+++ b/test/implementations/caching/cache/CacheTest_PushAndPop.cpp
@@ -0,0 +1,133 @@
+#include "testutils/CacheTest.h"
+
+#include "../../../../implementations/caching/cache/Cache.h"
+#include "testutils/MinimalKeyType.h"
+#include "testutils/MinimalValueType.h"
+
+using ::testing::Test;
+
+using namespace blockstore::caching;
+
+class CacheTest_PushAndPop: public CacheTest {};
+
+TEST_F(CacheTest_PushAndPop, PopNonExistingEntry_EmptyCache) {
+  EXPECT_EQ(boost::none, pop(10));
+}
+
+TEST_F(CacheTest_PushAndPop, PopNonExistingEntry_NonEmptyCache) {
+  push(9, 10);
+  EXPECT_EQ(boost::none, pop(10));
+}
+
+TEST_F(CacheTest_PushAndPop, PopNonExistingEntry_FullCache) {
+  //Add a lot of even numbered keys
+  for (unsigned int i = 0; i < Cache::MAX_ENTRIES; ++i) {
+    push(2*i, 2*i);
+  }
+  //Request an odd numbered key
+  EXPECT_EQ(boost::none, pop(9));
+}
+
+TEST_F(CacheTest_PushAndPop, OneEntry) {
+  push(10, 20);
+  EXPECT_EQ(20, pop(10).value());
+}
+
+TEST_F(CacheTest_PushAndPop, MultipleEntries) {
+  push(10, 20);
+  push(20, 30);
+  push(30, 40);
+  EXPECT_EQ(30, pop(20).value());
+  EXPECT_EQ(20, pop(10).value());
+  EXPECT_EQ(40, pop(30).value());
+}
+
+TEST_F(CacheTest_PushAndPop, FullCache) {
+  for(unsigned int i = 0; i < Cache::MAX_ENTRIES; ++i) {
+    push(i, 2*i);
+  }
+  for(unsigned int i = 0; i < Cache::MAX_ENTRIES; ++i) {
+    EXPECT_EQ(2*i, pop(i).value());
+  }
+}
+
+TEST_F(CacheTest_PushAndPop, FullCache_PushNonOrdered_PopOrdered) {
+  for(unsigned int i = 1; i < Cache::MAX_ENTRIES; i += 2) {
+    push(i, 2*i);
+  }
+  for(unsigned int i = 0; i < Cache::MAX_ENTRIES; i += 2) {
+    push(i, 2*i);
+  }
+  for(unsigned int i = 0; i < Cache::MAX_ENTRIES; ++i) {
+    EXPECT_EQ(2*i, pop(i).value());
+  }
+}
+
+TEST_F(CacheTest_PushAndPop, FullCache_PushOrdered_PopNonOrdered) {
+  for(unsigned int i = 0; i < Cache::MAX_ENTRIES; ++i) {
+    push(i, 2*i);
+  }
+  for(unsigned int i = 1; i < Cache::MAX_ENTRIES; i += 2) {
+    EXPECT_EQ(2*i, pop(i).value());
+  }
+  for(unsigned int i = 0; i < Cache::MAX_ENTRIES; i += 2) {
+    EXPECT_EQ(2*i, pop(i).value());
+  }
+}
+
+int roundDownToEven(int number) {
+  if (number % 2 == 0) {
+    return number;
+  } else {
+    return number - 1;
+  }
+}
+
+int roundDownToOdd(int number) {
+  if (number % 2 != 0) {
+    return number;
+  } else {
+    return number - 1;
+  }
+}
+
+TEST_F(CacheTest_PushAndPop, FullCache_PushNonOrdered_PopNonOrdered) {
+  for(int i = roundDownToEven(Cache::MAX_ENTRIES - 1); i >= 0; i -= 2) {
+    push(i, 2*i);
+  }
+  for(unsigned int i = 1; i < Cache::MAX_ENTRIES; i += 2) {
+    push(i, 2*i);
+  }
+  for(int i = roundDownToOdd(Cache::MAX_ENTRIES-1); i >= 0; i -= 2) {
+    EXPECT_EQ(2*i, pop(i).value());
+  }
+  for(unsigned int i = 0; i < Cache::MAX_ENTRIES; i += 2) {
+    EXPECT_EQ(2*i, pop(i).value());
+  }
+}
+
+TEST_F(CacheTest_PushAndPop, MoreThanFullCache) {
+  for(unsigned int i = 0; i < Cache::MAX_ENTRIES + 2; ++i) {
+    push(i, 2*i);
+  }
+  //Check that the oldest two elements got deleted automatically
+  EXPECT_EQ(boost::none, pop(0));
+  EXPECT_EQ(boost::none, pop(1));
+  //Check the other elements are still there
+  for(unsigned int i = 2; i < Cache::MAX_ENTRIES + 2; ++i) {
+    EXPECT_EQ(2*i, pop(i).value());
+  }
+}
+
+TEST_F(CacheTest_PushAndPop, AfterTimeout) {
+  constexpr double TIMEOUT1_SEC = Cache::MAX_LIFETIME_SEC * 3/4;
+  constexpr double TIMEOUT2_SEC = Cache::PURGE_LIFETIME_SEC * 3/4;
+  static_assert(TIMEOUT1_SEC + TIMEOUT2_SEC > Cache::MAX_LIFETIME_SEC, "Ensure that our chosen timeouts push the first entry out of the cache");
+
+  push(10, 20);
+  boost::this_thread::sleep_for(boost::chrono::milliseconds(static_cast<int>(1000 * TIMEOUT1_SEC)));
+  push(20, 30);
+  boost::this_thread::sleep_for(boost::chrono::milliseconds(static_cast<int>(1000 * TIMEOUT2_SEC)));
+  EXPECT_EQ(boost::none, pop(10));
+  EXPECT_EQ(30, pop(20).value());
+}
diff --git a/test/implementations/caching/cache/PeriodicTaskTest.cpp b/test/implementations/caching/cache/PeriodicTaskTest.cpp
new file mode 100644
index 00000000..d49492ad
--- /dev/null
+++ b/test/implementations/caching/cache/PeriodicTaskTest.cpp
@@ -0,0 +1,63 @@
+#include <google/gtest/gtest.h>
+
+#include "../../../../implementations/caching/cache/PeriodicTask.h"
+
+#include <mutex>
+#include <condition_variable>
+#include <atomic>
+
+using ::testing::Test;
+using std::mutex;
+using std::unique_lock;
+using std::condition_variable;
+
+using namespace blockstore::caching;
+
+class AtomicCounter {
+public:
+  AtomicCounter(int count): _mutex(), _cv(), _counter(count) {}
+
+  void decrease() {
+    unique_lock<mutex> lock(_mutex);
+    --_counter;
+    _cv.notify_all();
+  }
+
+  void waitForZero() {
+    unique_lock<mutex> lock(_mutex);
+    _cv.wait(lock, [this] () {return _counter <= 0;});
+  }
+private:
+  mutex _mutex;
+  condition_variable _cv;
+  int _counter;
+};
+
+class PeriodicTaskTest: public Test {
+};
+
+TEST_F(PeriodicTaskTest, DoesntDeadlockInDestructorWhenDestructedImmediately) {
+  PeriodicTask task([](){}, 1);
+}
+
+TEST_F(PeriodicTaskTest, CallsCallbackAtLeast10Times) {
+  AtomicCounter counter(10);
+
+  PeriodicTask task([&counter](){
+    counter.decrease();
+  }, 0.001);
+
+  counter.waitForZero();
+}
+
+TEST_F(PeriodicTaskTest, DoesntCallCallbackAfterDestruction) {
+  std::atomic<int> callCount(0);
+  {
+    PeriodicTask task([&callCount](){
+      callCount += 1;
+    }, 0.001);
+  }
+  int callCountDirectlyAfterDestruction = callCount;
+  boost::this_thread::sleep_for(boost::chrono::seconds(1));
+  EXPECT_EQ(callCountDirectlyAfterDestruction, callCount);
+}
diff --git a/test/implementations/caching/cache/QueueMapTest_MemoryLeak.cpp b/test/implementations/caching/cache/QueueMapTest_MemoryLeak.cpp
new file mode 100644
index 00000000..74012fc0
--- /dev/null
+++ b/test/implementations/caching/cache/QueueMapTest_MemoryLeak.cpp
@@ -0,0 +1,87 @@
+#include "testutils/QueueMapTest.h"
+
+// Tests that QueueMap calls destructors correctly.
+// This is needed, because QueueMap does its own memory management.
+class QueueMapTest_MemoryLeak: public QueueMapTest {
+public:
+  void EXPECT_NUM_INSTANCES(int num) {
+    EXPECT_EQ(num, MinimalKeyType::instances);
+    EXPECT_EQ(num, MinimalValueType::instances);
+  }
+};
+
+TEST_F(QueueMapTest_MemoryLeak, Empty) {
+  EXPECT_NUM_INSTANCES(0);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingOne) {
+  push(2, 3);
+  EXPECT_NUM_INSTANCES(1);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingTwo) {
+  push(2, 3);
+  push(3, 4);
+  EXPECT_NUM_INSTANCES(2);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingTwoAndPoppingOldest) {
+  push(2, 3);
+  push(3, 4);
+  pop();
+  EXPECT_NUM_INSTANCES(1);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingTwoAndPoppingFirst) {
+  push(2, 3);
+  push(3, 4);
+  pop(2);
+  EXPECT_NUM_INSTANCES(1);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingTwoAndPoppingLast) {
+  push(2, 3);
+  push(3, 4);
+  pop(3);
+  EXPECT_NUM_INSTANCES(1);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingOnePoppingOne) {
+  push(2, 3);
+  pop();
+  EXPECT_NUM_INSTANCES(0);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingOnePoppingOnePerKey) {
+  push(2, 3);
+  pop(2);
+  EXPECT_NUM_INSTANCES(0);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingOnePoppingOnePushingOne) {
+  push(2, 3);
+  pop();
+  push(3, 4);
+  EXPECT_NUM_INSTANCES(1);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingOnePoppingOnePerKeyPushingOne) {
+  push(2, 3);
+  pop(2);
+  push(3, 4);
+  EXPECT_NUM_INSTANCES(1);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingOnePoppingOnePushingSame) {
+  push(2, 3);
+  pop();
+  push(2, 3);
+  EXPECT_NUM_INSTANCES(1);
+}
+
+TEST_F(QueueMapTest_MemoryLeak, AfterPushingOnePoppingOnePerKeyPushingSame) {
+  push(2, 3);
+  pop(2);
+  push(2, 3);
+  EXPECT_NUM_INSTANCES(1);
+}
diff --git a/test/implementations/caching/cache/QueueMapTest_MoveConstructor.cpp b/test/implementations/caching/cache/QueueMapTest_MoveConstructor.cpp
new file mode 100644
index 00000000..4a1f15db
--- /dev/null
+++ b/test/implementations/caching/cache/QueueMapTest_MoveConstructor.cpp
@@ -0,0 +1,51 @@
+#include <google/gtest/gtest.h>
+#include <memory>
+#include "../../../../implementations/caching/cache/QueueMap.h"
+#include "testutils/MinimalKeyType.h"
+#include "testutils/CopyableMovableValueType.h"
+
+using namespace blockstore::caching;
+
+using ::testing::Test;
+using std::unique_ptr;
+using std::make_unique;
+
+//Test that QueueMap uses a move constructor for Value if possible
+class QueueMapTest_MoveConstructor: public Test {
+public:
+  QueueMapTest_MoveConstructor() {
+    CopyableMovableValueType::numCopyConstructorCalled = 0;
+    map = make_unique<QueueMap<MinimalKeyType, CopyableMovableValueType>>();
+  }
+  unique_ptr<QueueMap<MinimalKeyType, CopyableMovableValueType>> map;
+};
+
+TEST_F(QueueMapTest_MoveConstructor, PushingAndPopping_MoveIntoMap) {
+  map->push(MinimalKeyType::create(0), CopyableMovableValueType(2));
+  CopyableMovableValueType val = map->pop().value();
+  val.value(); //Access it to avoid the compiler optimizing the assignment away
+  EXPECT_EQ(0, CopyableMovableValueType::numCopyConstructorCalled);
+}
+
+TEST_F(QueueMapTest_MoveConstructor, PushingAndPoppingPerKey_MoveIntoMap) {
+  map->push(MinimalKeyType::create(0), CopyableMovableValueType(2));
+  CopyableMovableValueType val = map->pop(MinimalKeyType::create(0)).value();
+  val.value(); //Access it to avoid the compiler optimizing the assignment away
+  EXPECT_EQ(0, CopyableMovableValueType::numCopyConstructorCalled);
+}
+
+TEST_F(QueueMapTest_MoveConstructor, PushingAndPopping_CopyIntoMap) {
+  CopyableMovableValueType value(2);
+  map->push(MinimalKeyType::create(0), value);
+  CopyableMovableValueType val = map->pop().value();
+  val.value(); //Access it to avoid the compiler optimizing the assignment away
+  EXPECT_EQ(1, CopyableMovableValueType::numCopyConstructorCalled);
+}
+
+TEST_F(QueueMapTest_MoveConstructor, PushingAndPoppingPerKey_CopyIntoMap) {
+  CopyableMovableValueType value(2);
+  map->push(MinimalKeyType::create(0), value);
+  CopyableMovableValueType val = map->pop(MinimalKeyType::create(0)).value();
+  val.value(); //Access it to avoid the compiler optimizing the assignment away
+  EXPECT_EQ(1, CopyableMovableValueType::numCopyConstructorCalled);
+}
diff --git a/test/implementations/caching/cache/QueueMapTest_Peek.cpp b/test/implementations/caching/cache/QueueMapTest_Peek.cpp
new file mode 100644
index 00000000..ba3c7ead
--- /dev/null
+++ b/test/implementations/caching/cache/QueueMapTest_Peek.cpp
@@ -0,0 +1,34 @@
+#include "testutils/QueueMapTest.h"
+#include <boost/optional/optional_io.hpp>
+
+class QueueMapPeekTest: public QueueMapTest {};
+
+TEST_F(QueueMapPeekTest, PoppingFromEmpty) {
+  EXPECT_EQ(boost::none, peek());
+}
+
+TEST_F(QueueMapPeekTest, PushingOne) {
+  push(3, 2);
+  EXPECT_EQ(2, peek().value());
+}
+
+TEST_F(QueueMapPeekTest, PushingTwo) {
+  push(2, 3);
+  push(3, 4);
+  EXPECT_EQ(3, peek().value());
+  EXPECT_EQ(3, peek().value());
+  EXPECT_EQ(3, pop().value());
+  EXPECT_EQ(4, peek().value());
+  EXPECT_EQ(4, peek().value());
+  EXPECT_EQ(4, pop().value());
+  EXPECT_EQ(boost::none, peek());
+  EXPECT_EQ(boost::none, pop());
+}
+
+TEST_F(QueueMapPeekTest, AfterPushingTwoAndPoppingFirst) {
+  push(2, 3);
+  push(3, 4);
+  pop(2);
+  EXPECT_EQ(boost::none, pop(2));
+  EXPECT_EQ(4, peek().value());
+}
diff --git a/test/implementations/caching/cache/QueueMapTest_Size.cpp b/test/implementations/caching/cache/QueueMapTest_Size.cpp
new file mode 100644
index 00000000..e4d72c9d
--- /dev/null
+++ b/test/implementations/caching/cache/QueueMapTest_Size.cpp
@@ -0,0 +1,79 @@
+#include "testutils/QueueMapTest.h"
+
+class QueueMapTest_Size: public QueueMapTest {};
+
+TEST_F(QueueMapTest_Size, Empty) {
+  EXPECT_EQ(0, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingOne) {
+  push(2, 3);
+  EXPECT_EQ(1, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingTwo) {
+  push(2, 3);
+  push(3, 4);
+  EXPECT_EQ(2, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingTwoAndPoppingOldest) {
+  push(2, 3);
+  push(3, 4);
+  pop();
+  EXPECT_EQ(1, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingTwoAndPoppingFirst) {
+  push(2, 3);
+  push(3, 4);
+  pop(2);
+  EXPECT_EQ(1, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingTwoAndPoppingLast) {
+  push(2, 3);
+  push(3, 4);
+  pop(3);
+  EXPECT_EQ(1, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingOnePoppingOne) {
+  push(2, 3);
+  pop();
+  EXPECT_EQ(0, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingOnePoppingOnePerKey) {
+  push(2, 3);
+  pop(2);
+  EXPECT_EQ(0, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingOnePoppingOnePushingOne) {
+  push(2, 3);
+  pop();
+  push(3, 4);
+  EXPECT_EQ(1, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingOnePoppingOnePerKeyPushingOne) {
+  push(2, 3);
+  pop(2);
+  push(3, 4);
+  EXPECT_EQ(1, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingOnePoppingOnePushingSame) {
+  push(2, 3);
+  pop();
+  push(2, 3);
+  EXPECT_EQ(1, size());
+}
+
+TEST_F(QueueMapTest_Size, AfterPushingOnePoppingOnePerKeyPushingSame) {
+  push(2, 3);
+  pop(2);
+  push(2, 3);
+  EXPECT_EQ(1, size());
+}
diff --git a/test/implementations/caching/cache/QueueMapTest_Values.cpp b/test/implementations/caching/cache/QueueMapTest_Values.cpp
new file mode 100644
index 00000000..1acd5069
--- /dev/null
+++ b/test/implementations/caching/cache/QueueMapTest_Values.cpp
@@ -0,0 +1,150 @@
+#include "testutils/QueueMapTest.h"
+
+class QueueMapTest_Values: public QueueMapTest {};
+
+TEST_F(QueueMapTest_Values, PoppingFromEmpty) {
+  EXPECT_EQ(boost::none, pop());
+}
+
+TEST_F(QueueMapTest_Values, PoppingFromEmptyPerKey) {
+  EXPECT_EQ(boost::none, pop(2));
+}
+
+TEST_F(QueueMapTest_Values, PoppingNonexistingPerKey) {
+  push(3, 2);
+  EXPECT_EQ(boost::none, pop(2));
+}
+
+TEST_F(QueueMapTest_Values, PushingOne) {
+  push(3, 2);
+  EXPECT_EQ(2, pop(3).value());
+  EXPECT_EQ(boost::none, pop());
+}
+
+TEST_F(QueueMapTest_Values, PushingTwo) {
+  push(2, 3);
+  push(3, 4);
+  EXPECT_EQ(3, pop().value());
+  EXPECT_EQ(4, pop().value());
+  EXPECT_EQ(boost::none, pop());
+}
+
+TEST_F(QueueMapTest_Values, AfterPushingTwoAndPoppingFirst) {
+  push(2, 3);
+  push(3, 4);
+  pop(2);
+  EXPECT_EQ(boost::none, pop(2));
+  EXPECT_EQ(4, pop(3).value());
+  EXPECT_EQ(boost::none, pop());
+}
+
+TEST_F(QueueMapTest_Values, AfterPushingTwoAndPoppingLast) {
+  push(2, 3);
+  push(3, 4);
+  pop(3);
+  EXPECT_EQ(boost::none, pop(3));
+  EXPECT_EQ(3, pop(2).value());
+  EXPECT_EQ(boost::none, pop());
+}
+
+TEST_F(QueueMapTest_Values, AfterPushingOnePoppingOne) {
+  push(2, 3);
+  pop();
+  EXPECT_EQ(boost::none, pop());
+  EXPECT_EQ(boost::none, pop(2));
+}
+
+TEST_F(QueueMapTest_Values, AfterPushingOnePoppingOnePerKey) {
+  push(2, 3);
+  pop(2);
+  EXPECT_EQ(boost::none, pop());
+  EXPECT_EQ(boost::none, pop(2));
+}
+
+TEST_F(QueueMapTest_Values, AfterPushingOnePoppingOnePushingOne) {
+  push(2, 3);
+  pop();
+  push(3, 4);
+  EXPECT_EQ(boost::none, pop(2));
+  EXPECT_EQ(4, pop(3).value());
+  EXPECT_EQ(boost::none, pop());
+}
+
+TEST_F(QueueMapTest_Values, AfterPushingOnePoppingOnePerKeyPushingOne) {
+  push(2, 3);
+  pop(2);
+  push(3, 4);
+  EXPECT_EQ(boost::none, pop(2));
+  EXPECT_EQ(4, pop(3).value());
+  EXPECT_EQ(boost::none, pop());
+}
+
+TEST_F(QueueMapTest_Values, PushingSomePoppingMiddlePerKey) {
+  push(1, 2);
+  push(2, 3);
+  push(3, 4);
+  push(4, 5);
+  push(5, 6);
+  EXPECT_EQ(3, pop(2).value());
+  EXPECT_EQ(5, pop(4).value());
+  EXPECT_EQ(2, pop().value());
+  EXPECT_EQ(4, pop().value());
+  EXPECT_EQ(6, pop().value());
+  EXPECT_EQ(boost::none, pop());
+}
+
+TEST_F(QueueMapTest_Values, PushingSomePoppingFirstPerKey) {
+  push(1, 2);
+  push(2, 3);
+  push(3, 4);
+  push(4, 5);
+  push(5, 6);
+  EXPECT_EQ(2, pop(1).value());
+  EXPECT_EQ(3, pop(2).value());
+  EXPECT_EQ(4, pop().value());
+  EXPECT_EQ(5, pop().value());
+  EXPECT_EQ(6, pop().value());
+  EXPECT_EQ(boost::none, pop());
+}
+
+TEST_F(QueueMapTest_Values, PushingSomePoppingLastPerKey) {
+  push(1, 2);
+  push(2, 3);
+  push(3, 4);
+  push(4, 5);
+  push(5, 6);
+  EXPECT_EQ(6, pop(5).value());
+  EXPECT_EQ(5, pop(4).value());
+  EXPECT_EQ(2, pop().value());
+  EXPECT_EQ(3, pop().value());
+  EXPECT_EQ(4, pop().value());
+  EXPECT_EQ(boost::none, pop());
+}
+
+//This test forces the underlying datastructure (std::map or std::unordered_map) to grow and reallocate memory.
+//So it tests, that QueueMap still works after reallocating memory.
+TEST_F(QueueMapTest_Values, ManyValues) {
+  //Push 1 million entries
+  for (int i = 0; i < 1000000; ++i) {
+    push(i, 2*i);
+  }
+  //pop every other one by key
+  for (int i = 0; i < 1000000; i += 2) {
+    EXPECT_EQ(2*i, pop(i).value());
+  }
+  //pop the rest in queue order
+  for (int i = 1; i < 1000000; i += 2) {
+    EXPECT_EQ(2*i, peek().value());
+    EXPECT_EQ(2*i, pop().value());
+  }
+  EXPECT_EQ(0, size());
+  EXPECT_EQ(boost::none, pop());
+  EXPECT_EQ(boost::none, peek());
+}
+
+TEST_F(QueueMapTest_Values, PushAlreadyExistingValue) {
+  push(2, 3);
+  EXPECT_ANY_THROW(
+    push(2, 4);
+  );
+}
diff --git a/test/implementations/caching/cache/testutils/CacheTest.cpp b/test/implementations/caching/cache/testutils/CacheTest.cpp
new file mode 100644
index 00000000..b93bbccb
--- /dev/null
+++ b/test/implementations/caching/cache/testutils/CacheTest.cpp
@@ -0,0 +1,13 @@
+#include "CacheTest.h"
+
+void CacheTest::push(int key, int value) {
+  return _cache.push(MinimalKeyType::create(key), MinimalValueType::create(value));
+}
+
+boost::optional<int> CacheTest::pop(int key) {
+  boost::optional<MinimalValueType> entry = _cache.pop(MinimalKeyType::create(key));
+  if (!entry) {
+    return boost::none;
+  }
+  return entry->value();
+}
diff --git a/test/implementations/caching/cache/testutils/CacheTest.h b/test/implementations/caching/cache/testutils/CacheTest.h
new file mode 100644
index 00000000..61769936
--- /dev/null
+++ b/test/implementations/caching/cache/testutils/CacheTest.h
@@ -0,0 +1,25 @@
+#pragma once
+#ifndef BLOCKS_MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_CACHING_CACHE_TESTUTILS_QUEUEMAPTEST_H_
+#define BLOCKS_MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_CACHING_CACHE_TESTUTILS_QUEUEMAPTEST_H_
+
+#include <google/gtest/gtest.h>
+#include "../../../../../implementations/caching/cache/Cache.h"
+#include "MinimalKeyType.h"
+#include "MinimalValueType.h"
+#include <boost/optional.hpp>
+
+// This class is a parent class for tests on QueueMap.
+// It offers functions to work with a QueueMap test object which is built using types having only the minimal type requirements.
+// Furthermore, the class checks that there are no memory leaks left after destructing the QueueMap (by counting leftover instances of Keys/Values).
+class CacheTest: public ::testing::Test {
+public:
+  void push(int key, int value);
+  boost::optional<int> pop(int key);
+
+  using Cache = blockstore::caching::Cache<MinimalKeyType, MinimalValueType>;
+
+private:
+  Cache _cache;
+};
+
+#endif
diff --git a/test/implementations/caching/cache/testutils/CopyableMovableValueType.cpp b/test/implementations/caching/cache/testutils/CopyableMovableValueType.cpp
new file mode 100644
index 00000000..cf23bd88
--- /dev/null
+++ b/test/implementations/caching/cache/testutils/CopyableMovableValueType.cpp
@@ -0,0 +1,3 @@
+#include "CopyableMovableValueType.h"
+
+int CopyableMovableValueType::numCopyConstructorCalled = 0;
diff --git a/test/implementations/caching/cache/testutils/CopyableMovableValueType.h b/test/implementations/caching/cache/testutils/CopyableMovableValueType.h
new file mode 100644
index 00000000..c3201423
--- /dev/null
+++ b/test/implementations/caching/cache/testutils/CopyableMovableValueType.h
@@ -0,0 +1,23 @@
+#pragma once
+#ifndef MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_CACHING_CACHE_TESTUTILS_COPYABLEMOVABLEVALUETYPE_H_
+#define MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_CACHING_CACHE_TESTUTILS_COPYABLEMOVABLEVALUETYPE_H_
+
+class CopyableMovableValueType {
+public:
+  static int numCopyConstructorCalled;
+  CopyableMovableValueType(int value): _value(value) {}
+  CopyableMovableValueType(const CopyableMovableValueType &rhs): CopyableMovableValueType(rhs._value) {
+    ++numCopyConstructorCalled;
+  }
+  CopyableMovableValueType(CopyableMovableValueType &&rhs): CopyableMovableValueType(rhs._value) {
+    //Don't increase numCopyConstructorCalled
+  }
+  int value() const {
+    return _value;
+  }
+private:
+  int _value;
+};
+
+
+#endif
diff --git a/test/implementations/caching/cache/testutils/MinimalKeyType.cpp b/test/implementations/caching/cache/testutils/MinimalKeyType.cpp
new file mode 100644
index 00000000..f6b327ff
--- /dev/null
+++ b/test/implementations/caching/cache/testutils/MinimalKeyType.cpp
@@ -0,0 +1,3 @@
+#include "MinimalKeyType.h"
+
+int MinimalKeyType::instances = 0;
diff --git a/test/implementations/caching/cache/testutils/MinimalKeyType.h b/test/implementations/caching/cache/testutils/MinimalKeyType.h
new file mode 100644
index 00000000..9133d1f8
--- /dev/null
+++ b/test/implementations/caching/cache/testutils/MinimalKeyType.h
@@ -0,0 +1,47 @@
+#pragma once
+#ifndef BLOCKS_MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_CACHING_CACHE_TESTUTILS_MINIMALKEYTYPE_H_
+#define BLOCKS_MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_CACHING_CACHE_TESTUTILS_MINIMALKEYTYPE_H_
+
+#include <unordered_map>
+
+// This is a not-default-constructible Key type
+class MinimalKeyType {
+public:
+  static int instances;
+
+  static MinimalKeyType create(int value) {
+    return MinimalKeyType(value);
+  }
+
+  MinimalKeyType(const MinimalKeyType &rhs): MinimalKeyType(rhs.value()) {
+  }
+
+  ~MinimalKeyType() {
+    --instances;
+  }
+
+  int value() const {
+    return _value;
+  }
+
+private:
+  MinimalKeyType(int value): _value(value) {
+    ++instances;
+  }
+
+  int _value;
+};
+
+namespace std {
+template <> struct hash<MinimalKeyType> {
+  size_t operator()(const MinimalKeyType &obj) const {
+    return obj.value();
+  }
+};
+}
+
+inline bool operator==(const MinimalKeyType &lhs, const MinimalKeyType &rhs) {
+  return lhs.value() == rhs.value();
+}
+
+#endif
diff --git a/test/implementations/caching/cache/testutils/MinimalValueType.cpp b/test/implementations/caching/cache/testutils/MinimalValueType.cpp
new file mode 100644
index 00000000..f5cbdbae
--- /dev/null
+++ b/test/implementations/caching/cache/testutils/MinimalValueType.cpp
@@ -0,0 +1,3 @@
+#include "MinimalValueType.h"
+
+int MinimalValueType::instances = 0;
diff --git a/test/implementations/caching/cache/testutils/MinimalValueType.h b/test/implementations/caching/cache/testutils/MinimalValueType.h
new file mode 100644
index 00000000..9e48e43e
--- /dev/null
+++ b/test/implementations/caching/cache/testutils/MinimalValueType.h
@@ -0,0 +1,44 @@
+#pragma once
+#ifndef BLOCKS_MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_CACHING_CACHE_TESTUTILS_MINIMALVALUETYPE_H_
+#define BLOCKS_MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_CACHING_CACHE_TESTUTILS_MINIMALVALUETYPE_H_
+
+#include <messmer/cpp-utils/macros.h>
+#include <cassert>
+
+// This is a not-default-constructible non-copyable but moveable Value type
+class MinimalValueType {
+public:
+  static int instances;
+
+  static MinimalValueType create(int value) {
+    return MinimalValueType(value);
+  }
+
+  MinimalValueType(MinimalValueType &&rhs): MinimalValueType(rhs.value()) {
+    rhs._isMoved = true;
+  }
+
+  ~MinimalValueType() {
+    assert(!_isDestructed);
+    --instances;
+    _isDestructed = true;
+  }
+
+  int value() const {
+    assert(!_isMoved && !_isDestructed);
+    return _value;
+  }
+
+private:
+  MinimalValueType(int value): _value(value), _isMoved(false), _isDestructed(false) {
+    ++instances;
+  }
+
+  int _value;
+  bool _isMoved;
+  bool _isDestructed;
+
+  DISALLOW_COPY_AND_ASSIGN(MinimalValueType);
+};
+
+#endif
diff --git a/test/implementations/caching/cache/testutils/QueueMapTest.cpp b/test/implementations/caching/cache/testutils/QueueMapTest.cpp
new file mode 100644
index 00000000..f61b41a3
--- /dev/null
+++ b/test/implementations/caching/cache/testutils/QueueMapTest.cpp
@@ -0,0 +1,45 @@
+#include "QueueMapTest.h"
+
+QueueMapTest::QueueMapTest() {
+  MinimalKeyType::instances = 0;
+  MinimalValueType::instances = 0;
+  _map = std::make_unique<blockstore::caching::QueueMap<MinimalKeyType, MinimalValueType>>();
+}
+
+QueueMapTest::~QueueMapTest() {
+  _map.reset();
+  EXPECT_EQ(0, MinimalKeyType::instances);
+  EXPECT_EQ(0, MinimalValueType::instances);
+}
+
+void QueueMapTest::push(int key, int value) {
+  _map->push(MinimalKeyType::create(key), MinimalValueType::create(value));
+}
+
+boost::optional<int> QueueMapTest::pop() {
+  auto elem = _map->pop();
+  if (!elem) {
+    return boost::none;
+  }
+  return elem.value().value();
+}
+
+boost::optional<int> QueueMapTest::pop(int key) {
+  auto elem = _map->pop(MinimalKeyType::create(key));
+  if (!elem) {
+    return boost::none;
+  }
+  return elem.value().value();
+}
+
+boost::optional<int> QueueMapTest::peek() {
+  auto elem = _map->peek();
+  if (!elem) {
+    return boost::none;
+  }
+  return elem.value().value();
+}
+
+int QueueMapTest::size() {
+  return _map->size();
+}
diff --git a/test/implementations/caching/cache/testutils/QueueMapTest.h b/test/implementations/caching/cache/testutils/QueueMapTest.h
new file mode 100644
index 00000000..e49ad93f
--- /dev/null
+++ b/test/implementations/caching/cache/testutils/QueueMapTest.h
@@ -0,0 +1,32 @@
+#pragma once
+#ifndef BLOCKS_MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_CACHING_CACHE_TESTUTILS_QUEUEMAPTEST_H_
+#define BLOCKS_MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_CACHING_CACHE_TESTUTILS_QUEUEMAPTEST_H_
+
+#include <google/gtest/gtest.h>
+#include <memory>
+#include "../../../../../implementations/caching/cache/QueueMap.h"
+#include "MinimalKeyType.h"
+#include "MinimalValueType.h"
+#include <boost/optional.hpp>
+
+// This class is a parent class for tests on QueueMap.
+// It offers functions to work with a QueueMap test object which is built using types having only the minimal type requirements.
+// Furthermore, the class checks that there are no memory leaks left after destructing the QueueMap (by counting leftover instances of Keys/Values).
+class QueueMapTest: public ::testing::Test {
+public:
+  QueueMapTest();
+  ~QueueMapTest();
+
+  void push(int key, int value);
+  boost::optional<int> pop();
+  boost::optional<int> pop(int key);
+  boost::optional<int> peek();
+  int size();
+
+private:
+  std::unique_ptr<blockstore::caching::QueueMap<MinimalKeyType, MinimalValueType>> _map;
+};
+
+
+
+#endif
diff --git a/test/implementations/encrypted/CipherTest.cpp b/test/implementations/encrypted/CipherTest.cpp
new file mode 100644
index 00000000..f5581b05
--- /dev/null
+++ b/test/implementations/encrypted/CipherTest.cpp
@@ -0,0 +1,226 @@
+#include <google/gtest/gtest.h>
+#include "../../../implementations/encrypted/ciphers/Cipher.h"
+#include "../../../implementations/encrypted/ciphers/AES256_CFB.h"
+#include "../../../implementations/encrypted/ciphers/AES256_GCM.h"
+#include "testutils/FakeAuthenticatedCipher.h"
+
+#include <messmer/cpp-utils/data/DataFixture.h>
+#include <messmer/cpp-utils/data/Data.h>
+
+ #include <boost/optional/optional_io.hpp>
+
+using namespace blockstore::encrypted;
+using cpputils::Data;
+using cpputils::DataFixture;
+
+template<class Cipher>
+class CipherTest: public ::testing::Test {
+public:
+  BOOST_CONCEPT_ASSERT((CipherConcept<Cipher>));
+  typename Cipher::EncryptionKey encKey = createKeyFixture();
+
+  static typename Cipher::EncryptionKey createKeyFixture(int seed = 0) {
+    Data data = DataFixture::generate(Cipher::EncryptionKey::BINARY_LENGTH, seed);
+    return Cipher::EncryptionKey::FromBinary(data.data());
+  }
+
+  void CheckEncryptThenDecryptIsIdentity(const Data &plaintext) {
+    Data ciphertext = Encrypt(plaintext);
+    Data decrypted = Decrypt(ciphertext);
+    EXPECT_EQ(plaintext, decrypted);
+  }
+
+  void CheckEncryptIsIndeterministic(const Data &plaintext) {
+    Data ciphertext = Encrypt(plaintext);
+    Data ciphertext2 = Encrypt(plaintext);
+    EXPECT_NE(ciphertext, ciphertext2);
+  }
+
+  void CheckEncryptedSize(const Data &plaintext) {
+    Data ciphertext = Encrypt(plaintext);
+    EXPECT_EQ(Cipher::ciphertextSize(plaintext.size()), ciphertext.size());
+  }
+
+  void ExpectDoesntDecrypt(const Data &ciphertext) {
+    auto decrypted = Cipher::decrypt((byte*)ciphertext.data(), ciphertext.size(), this->encKey);
+    EXPECT_FALSE(decrypted);
+  }
+
+  Data Encrypt(const Data &plaintext) {
+    return Cipher::encrypt((byte*)plaintext.data(), plaintext.size(), this->encKey);
+  }
+
+  Data Decrypt(const Data &ciphertext) {
+    return Cipher::decrypt((byte*)ciphertext.data(), ciphertext.size(), this->encKey).value();
+  }
+
+  static Data CreateZeroes(unsigned int size) {
+    return std::move(Data(size).FillWithZeroes());
+  }
+
+  static Data CreateData(unsigned int size, unsigned int seed = 0) {
+    return DataFixture::generate(size, seed);
+  }
+};
+
+TYPED_TEST_CASE_P(CipherTest);
+
+constexpr std::initializer_list<unsigned int> SIZES = {0, 1, 100, 1024, 5000, 1048576, 20971520};
+
+TYPED_TEST_P(CipherTest, Size) {
+  for (auto size: SIZES) {
+    EXPECT_EQ(size, TypeParam::ciphertextSize(TypeParam::plaintextSize(size)));
+    EXPECT_EQ(size, TypeParam::plaintextSize(TypeParam::ciphertextSize(size)));
+  }
+}
+
+TYPED_TEST_P(CipherTest, EncryptThenDecrypt_Zeroes) {
+  for (auto size: SIZES) {
+    Data plaintext = this->CreateZeroes(size);
+    this->CheckEncryptThenDecryptIsIdentity(plaintext);
+  }
+}
+
+TYPED_TEST_P(CipherTest, EncryptThenDecrypt_Data) {
+  for (auto size: SIZES) {
+    Data plaintext = this->CreateData(size);
+    this->CheckEncryptThenDecryptIsIdentity(plaintext);
+  }
+}
+
+TYPED_TEST_P(CipherTest, EncryptIsIndeterministic_Zeroes) {
+  for (auto size: SIZES) {
+    Data plaintext = this->CreateZeroes(size);
+    this->CheckEncryptIsIndeterministic(plaintext);
+  }
+}
+
+TYPED_TEST_P(CipherTest, EncryptIsIndeterministic_Data) {
+  for (auto size: SIZES) {
+    Data plaintext = this->CreateData(size);
+    this->CheckEncryptIsIndeterministic(plaintext);
+  }
+}
+
+TYPED_TEST_P(CipherTest, EncryptedSize) {
+  for (auto size: SIZES) {
+    Data plaintext = this->CreateData(size);
+    this->CheckEncryptedSize(plaintext);
+  }
+}
+
+TYPED_TEST_P(CipherTest, TryDecryptDataThatIsTooSmall) {
+  Data tooSmallCiphertext(TypeParam::ciphertextSize(0) - 1);
+  this->ExpectDoesntDecrypt(tooSmallCiphertext);
+}
+
+TYPED_TEST_P(CipherTest, TryDecryptDataThatIsMuchTooSmall_0) {
+  static_assert(TypeParam::ciphertextSize(0) > 0, "If this fails, the test case doesn't make sense.");
+  Data tooSmallCiphertext(0);
+  this->ExpectDoesntDecrypt(tooSmallCiphertext);
+}
+
+TYPED_TEST_P(CipherTest, TryDecryptDataThatIsMuchTooSmall_1) {
+  static_assert(TypeParam::ciphertextSize(0) > 1, "If this fails, the test case doesn't make sense.");
+  Data tooSmallCiphertext(1);
+  this->ExpectDoesntDecrypt(tooSmallCiphertext);
+}
+
+REGISTER_TYPED_TEST_CASE_P(CipherTest,
+    Size,
+    EncryptThenDecrypt_Zeroes,
+    EncryptThenDecrypt_Data,
+    EncryptIsIndeterministic_Zeroes,
+    EncryptIsIndeterministic_Data,
+    EncryptedSize,
+    TryDecryptDataThatIsTooSmall,
+    TryDecryptDataThatIsMuchTooSmall_0,
+    TryDecryptDataThatIsMuchTooSmall_1
+);
+
+template<class Cipher>
+class AuthenticatedCipherTest: public CipherTest<Cipher> {
+public:
+  Data zeroes1 = CipherTest<Cipher>::CreateZeroes(1);
+  Data plaintext1 = CipherTest<Cipher>::CreateData(1);
+  Data zeroes2 = CipherTest<Cipher>::CreateZeroes(100 * 1024);
+  Data plaintext2 = CipherTest<Cipher>::CreateData(100 * 1024);
+};
+
+TYPED_TEST_CASE_P(AuthenticatedCipherTest);
+
+TYPED_TEST_P(AuthenticatedCipherTest, ModifyFirstByte_Zeroes_Size1) {
+  Data ciphertext = this->Encrypt(this->zeroes1);
+  *(byte*)ciphertext.data() = *(byte*)ciphertext.data() + 1;
+  this->ExpectDoesntDecrypt(ciphertext);
+}
+
+TYPED_TEST_P(AuthenticatedCipherTest, ModifyFirstByte_Data_Size1) {
+  Data ciphertext = this->Encrypt(this->plaintext1);
+  *(byte*)ciphertext.data() = *(byte*)ciphertext.data() + 1;
+  this->ExpectDoesntDecrypt(ciphertext);
+}
+
+TYPED_TEST_P(AuthenticatedCipherTest, ModifyFirstByte_Zeroes) {
+  Data ciphertext = this->Encrypt(this->zeroes2);
+  *(byte*)ciphertext.data() = *(byte*)ciphertext.data() + 1;
+  this->ExpectDoesntDecrypt(ciphertext);
+}
+
+TYPED_TEST_P(AuthenticatedCipherTest, ModifyFirstByte_Data) {
+  Data ciphertext = this->Encrypt(this->plaintext2);
+  *(byte*)ciphertext.data() = *(byte*)ciphertext.data() + 1;
+  this->ExpectDoesntDecrypt(ciphertext);
+}
+
+TYPED_TEST_P(AuthenticatedCipherTest, ModifyLastByte_Zeroes) {
+  Data ciphertext = this->Encrypt(this->zeroes2);
+  ((byte*)ciphertext.data())[ciphertext.size() - 1] = ((byte*)ciphertext.data())[ciphertext.size() - 1] + 1;
+  this->ExpectDoesntDecrypt(ciphertext);
+}
+
+TYPED_TEST_P(AuthenticatedCipherTest, ModifyLastByte_Data) {
+  Data ciphertext = this->Encrypt(this->plaintext2);
+  ((byte*)ciphertext.data())[ciphertext.size() - 1] = ((byte*)ciphertext.data())[ciphertext.size() - 1] + 1;
+  this->ExpectDoesntDecrypt(ciphertext);
+}
+
+TYPED_TEST_P(AuthenticatedCipherTest, ModifyMiddleByte_Zeroes) {
+  Data ciphertext = this->Encrypt(this->zeroes2);
+  ((byte*)ciphertext.data())[ciphertext.size()/2] = ((byte*)ciphertext.data())[ciphertext.size()/2] + 1;
+  this->ExpectDoesntDecrypt(ciphertext);
+}
+
+TYPED_TEST_P(AuthenticatedCipherTest, ModifyMiddleByte_Data) {
+  Data ciphertext = this->Encrypt(this->plaintext2);
+  ((byte*)ciphertext.data())[ciphertext.size()/2] = ((byte*)ciphertext.data())[ciphertext.size()/2] + 1;
+  this->ExpectDoesntDecrypt(ciphertext);
+}
+
+TYPED_TEST_P(AuthenticatedCipherTest, TryDecryptZeroesData) {
+  this->ExpectDoesntDecrypt(this->zeroes2);
+}
+
+TYPED_TEST_P(AuthenticatedCipherTest, TryDecryptRandomData) {
+  this->ExpectDoesntDecrypt(this->plaintext2);
+}
+
+REGISTER_TYPED_TEST_CASE_P(AuthenticatedCipherTest,
+  ModifyFirstByte_Zeroes_Size1,
+  ModifyFirstByte_Zeroes,
+  ModifyFirstByte_Data_Size1,
+  ModifyFirstByte_Data,
+  ModifyLastByte_Zeroes,
+  ModifyLastByte_Data,
+  ModifyMiddleByte_Zeroes,
+  ModifyMiddleByte_Data,
+  TryDecryptZeroesData,
+  TryDecryptRandomData
+);
+
+
+INSTANTIATE_TYPED_TEST_CASE_P(Fake, CipherTest, FakeAuthenticatedCipher);
+INSTANTIATE_TYPED_TEST_CASE_P(Fake, AuthenticatedCipherTest, FakeAuthenticatedCipher);
+INSTANTIATE_TYPED_TEST_CASE_P(AES256_CFB, CipherTest, AES256_CFB); //CFB mode is not authenticated
+INSTANTIATE_TYPED_TEST_CASE_P(AES256_GCM, CipherTest, AES256_GCM);
+INSTANTIATE_TYPED_TEST_CASE_P(AES256_GCM, AuthenticatedCipherTest, AES256_GCM);
diff --git a/test/implementations/encrypted/EncryptedBlockStoreTest.cpp b/test/implementations/encrypted/EncryptedBlockStoreTest.cpp
deleted file mode 100644
index b5c6eb29..00000000
--- a/test/implementations/encrypted/EncryptedBlockStoreTest.cpp
+++ /dev/null
@@ -1,24 +0,0 @@
-#include "../../../implementations/encrypted/EncryptedBlockStore.h"
-#include "../../../implementations/testfake/FakeBlockStore.h"
-#include "../../testutils/BlockStoreTest.h"
-#include "google/gtest/gtest.h"
-
-
-using blockstore::BlockStore;
-using blockstore::encrypted::EncryptedBlockStore;
-using blockstore::encrypted::EncryptionKey;
-using blockstore::testfake::FakeBlockStore;
-
-using std::unique_ptr;
-using std::make_unique;
-
-class EncryptedBlockStoreTestFixture: public BlockStoreTestFixture {
-public:
-  unique_ptr<BlockStore> createBlockStore() override {
-    return make_unique<EncryptedBlockStore>(make_unique<FakeBlockStore>(), EncryptionKey::FromString("1491BB4932A389EE14BC7090A272EE5517627CFA147A971A8E6E747E0C772972"));
-  }
-};
-
-INSTANTIATE_TYPED_TEST_CASE_P(Encrypted, BlockStoreTest, EncryptedBlockStoreTestFixture);
-
-//TODO Add specific tests, for example loading it with a different key doesn't work
diff --git a/test/implementations/encrypted/EncryptedBlockStoreTest_Generic.cpp b/test/implementations/encrypted/EncryptedBlockStoreTest_Generic.cpp
new file mode 100644
index 00000000..5507151d
--- /dev/null
+++ b/test/implementations/encrypted/EncryptedBlockStoreTest_Generic.cpp
@@ -0,0 +1,40 @@
+#include "../../../implementations/encrypted/ciphers/AES256_GCM.h"
+#include "../../../implementations/encrypted/ciphers/AES256_CFB.h"
+#include "../../../implementations/encrypted/ciphers/Cipher.h"
+#include "../../../implementations/encrypted/EncryptedBlockStore.h"
+#include "../../../implementations/testfake/FakeBlockStore.h"
+#include "../../testutils/BlockStoreTest.h"
+#include "testutils/FakeAuthenticatedCipher.h"
+#include "google/gtest/gtest.h"
+
+using ::testing::Test;
+
+using blockstore::BlockStore;
+using blockstore::encrypted::EncryptedBlockStore;
+using blockstore::testfake::FakeBlockStore;
+using blockstore::encrypted::AES256_GCM;
+using blockstore::encrypted::AES256_CFB;
+
+using std::unique_ptr;
+using std::make_unique;
+
+using cpputils::Data;
+using cpputils::DataFixture;
+
+template<class Cipher>
+class EncryptedBlockStoreTestFixture: public BlockStoreTestFixture {
+public:
+  unique_ptr<BlockStore> createBlockStore() override {
+    return make_unique<EncryptedBlockStore<Cipher>>(make_unique<FakeBlockStore>(), createKeyFixture());
+  }
+
+private:
+  static typename Cipher::EncryptionKey createKeyFixture(int seed = 0) {
+    Data data = DataFixture::generate(Cipher::EncryptionKey::BINARY_LENGTH, seed);
+    return Cipher::EncryptionKey::FromBinary(data.data());
+  }
+};
+
+INSTANTIATE_TYPED_TEST_CASE_P(Encrypted_FakeCipher, BlockStoreTest, EncryptedBlockStoreTestFixture<FakeAuthenticatedCipher>);
+INSTANTIATE_TYPED_TEST_CASE_P(Encrypted_AES256_GCM, BlockStoreTest, EncryptedBlockStoreTestFixture<AES256_GCM>);
+INSTANTIATE_TYPED_TEST_CASE_P(Encrypted_AES256_CFB, BlockStoreTest, EncryptedBlockStoreTestFixture<AES256_CFB>);
diff --git a/test/implementations/encrypted/EncryptedBlockStoreTest_Specific.cpp b/test/implementations/encrypted/EncryptedBlockStoreTest_Specific.cpp
new file mode 100644
index 00000000..0a6ca336
--- /dev/null
+++ b/test/implementations/encrypted/EncryptedBlockStoreTest_Specific.cpp
@@ -0,0 +1,113 @@
+#include <google/gtest/gtest.h>
+#include "testutils/FakeAuthenticatedCipher.h"
+#include "../../../implementations/encrypted/EncryptedBlockStore.h"
+#include "../../../implementations/testfake/FakeBlockStore.h"
+#include "../../../utils/BlockStoreUtils.h"
+#include <messmer/cpp-utils/data/DataFixture.h>
+
+using ::testing::Test;
+
+using std::unique_ptr;
+using std::make_unique;
+
+using cpputils::DataFixture;
+using cpputils::Data;
+
+using blockstore::testfake::FakeBlockStore;
+
+using namespace blockstore::encrypted;
+
+class EncryptedBlockStoreTest: public Test {
+public:
+  static constexpr unsigned int BLOCKSIZE = 1024;
+  EncryptedBlockStoreTest():
+    _baseBlockStore(make_unique<FakeBlockStore>()),
+    baseBlockStore(_baseBlockStore.get()),
+    blockStore(make_unique<EncryptedBlockStore<FakeAuthenticatedCipher>>(std::move(_baseBlockStore), FakeAuthenticatedCipher::Key1())),
+    data(DataFixture::generate(BLOCKSIZE)) {
+  }
+  unique_ptr<FakeBlockStore> _baseBlockStore;
+  FakeBlockStore *baseBlockStore;
+  unique_ptr<EncryptedBlockStore<FakeAuthenticatedCipher>> blockStore;
+  Data data;
+
+  blockstore::Key CreateBlockDirectlyWithFixtureAndReturnKey() {
+    return blockStore->create(data)->key();
+  }
+
+  blockstore::Key CreateBlockWriteFixtureToItAndReturnKey() {
+    auto block = blockStore->create(Data(data.size()));
+    block->write(data.data(), 0, data.size());
+    return block->key();
+  }
+
+  void ModifyBaseBlock(const blockstore::Key &key) {
+    auto block = baseBlockStore->load(key);
+    uint8_t middle_byte = ((byte*)block->data())[10];
+    uint8_t new_middle_byte = middle_byte + 1;
+    block->write(&new_middle_byte, 10, 1);
+  }
+
+  blockstore::Key CopyBaseBlock(const blockstore::Key &key) {
+    auto source = baseBlockStore->load(key);
+    return blockstore::utils::copyToNewBlock(baseBlockStore, *source)->key();
+  }
+};
+
+TEST_F(EncryptedBlockStoreTest, LoadingWithSameKeyWorks_WriteOnCreate) {
+  auto key = CreateBlockDirectlyWithFixtureAndReturnKey();
+  auto loaded = blockStore->load(key);
+  EXPECT_NE(nullptr, loaded.get());
+  EXPECT_EQ(data.size(), loaded->size());
+  EXPECT_EQ(0, std::memcmp(data.data(), loaded->data(), data.size()));
+}
+
+TEST_F(EncryptedBlockStoreTest, LoadingWithSameKeyWorks_WriteSeparately) {
+  auto key = CreateBlockWriteFixtureToItAndReturnKey();
+  auto loaded = blockStore->load(key);
+  EXPECT_NE(nullptr, loaded.get());
+  EXPECT_EQ(data.size(), loaded->size());
+  EXPECT_EQ(0, std::memcmp(data.data(), loaded->data(), data.size()));
+}
+
+TEST_F(EncryptedBlockStoreTest, LoadingWithDifferentKeyDoesntWork_WriteOnCreate) {
+  auto key = CreateBlockDirectlyWithFixtureAndReturnKey();
+  blockStore->__setKey(FakeAuthenticatedCipher::Key2());
+  auto loaded = blockStore->load(key);
+  EXPECT_EQ(nullptr, loaded.get());
+}
+
+TEST_F(EncryptedBlockStoreTest, LoadingWithDifferentKeyDoesntWork_WriteSeparately) {
+  auto key = CreateBlockWriteFixtureToItAndReturnKey();
+  blockStore->__setKey(FakeAuthenticatedCipher::Key2());
+  auto loaded = blockStore->load(key);
+  EXPECT_EQ(nullptr, loaded.get());
+}
+
+TEST_F(EncryptedBlockStoreTest, LoadingModifiedBlockFails_WriteOnCreate) {
+  auto key = CreateBlockDirectlyWithFixtureAndReturnKey();
+  ModifyBaseBlock(key);
+  auto loaded = blockStore->load(key);
+  EXPECT_EQ(nullptr, loaded.get());
+}
+
+TEST_F(EncryptedBlockStoreTest, LoadingModifiedBlockFails_WriteSeparately) {
+  auto key = CreateBlockWriteFixtureToItAndReturnKey();
+  ModifyBaseBlock(key);
+  auto loaded = blockStore->load(key);
+  EXPECT_EQ(nullptr, loaded.get());
+}
+
+TEST_F(EncryptedBlockStoreTest, LoadingWithDifferentBlockIdFails_WriteOnCreate) {
+  auto key = CreateBlockDirectlyWithFixtureAndReturnKey();
+  auto key2 = CopyBaseBlock(key);
+  auto loaded = blockStore->load(key2);
+  EXPECT_EQ(nullptr, loaded.get());
+}
+
+TEST_F(EncryptedBlockStoreTest, LoadingWithDifferentBlockIdFails_WriteSeparately) {
+  auto key = CreateBlockWriteFixtureToItAndReturnKey();
+  auto key2 = CopyBaseBlock(key);
+  auto loaded = blockStore->load(key2);
+  EXPECT_EQ(nullptr, loaded.get());
+}
diff --git a/test/implementations/encrypted/testutils/FakeAuthenticatedCipher.cpp b/test/implementations/encrypted/testutils/FakeAuthenticatedCipher.cpp
new file mode 100644
index 00000000..719ae3f0
--- /dev/null
+++ b/test/implementations/encrypted/testutils/FakeAuthenticatedCipher.cpp
@@ -0,0 +1,3 @@
+#include "FakeAuthenticatedCipher.h"
+
+constexpr unsigned int FakeKey::BINARY_LENGTH;
diff --git a/test/implementations/encrypted/testutils/FakeAuthenticatedCipher.h b/test/implementations/encrypted/testutils/FakeAuthenticatedCipher.h
new file mode 100644
index 00000000..d99ff86d
--- /dev/null
+++ b/test/implementations/encrypted/testutils/FakeAuthenticatedCipher.h
@@ -0,0 +1,102 @@
+#pragma once
+#ifndef MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_ENCRYPTED_TESTUTILS_FAKEAUTHENTICATEDCIPHER_H_
+#define MESSMER_BLOCKSTORE_TEST_IMPLEMENTATIONS_ENCRYPTED_TESTUTILS_FAKEAUTHENTICATEDCIPHER_H_
+
+#include "../../../../implementations/encrypted/ciphers/Cipher.h"
+#include <messmer/cpp-utils/data/FixedSizeData.h>
+
+struct FakeKey {
+  FakeKey(uint8_t value_):value(value_) {}
+  static FakeKey CreateRandom() {
+    return FakeKey(rand());
+  }
+  static FakeKey FromBinary(const void *data) {
+    return FakeKey(*(uint8_t*)data);
+  }
+  static constexpr unsigned int BINARY_LENGTH = 1;
+
+  uint8_t value;
+};
+
+// This is a fake cipher that uses an indeterministic caesar chiffre and a 4-byte parity for a simple authentication mechanism
+class FakeAuthenticatedCipher {
+public:
+  BOOST_CONCEPT_ASSERT((blockstore::encrypted::CipherConcept<FakeAuthenticatedCipher>));
+
+  using EncryptionKey = FakeKey;
+
+  static EncryptionKey Key1() {
+    return FakeKey(5);
+  }
+  static EncryptionKey Key2() {
+    return FakeKey(63);
+  }
+
+  static constexpr unsigned int ciphertextSize(unsigned int plaintextBlockSize) {
+    return plaintextBlockSize + 5;
+  }
+
+  static constexpr unsigned int plaintextSize(unsigned int ciphertextBlockSize) {
+    return ciphertextBlockSize - 5;
+  }
+
+  static cpputils::Data encrypt(const byte *plaintext, unsigned int plaintextSize, const EncryptionKey &encKey) {
+    cpputils::Data result(ciphertextSize(plaintextSize));
+
+    //Add a random IV
+    uint8_t iv = rand();
+    std::memcpy(result.data(), &iv, 1);
+
+    //Use caesar chiffre on plaintext
+    _caesar((byte*)result.data() + 1, plaintext, plaintextSize, encKey.value + iv);
+
+    //Add parity information
+    int32_t parity = _parity((byte*)result.data(), plaintextSize + 1);
+    std::memcpy((byte*)result.data() + plaintextSize + 1, &parity, 4);
+
+    return result;
+  }
+
+  static boost::optional<cpputils::Data> decrypt(const byte *ciphertext, unsigned int ciphertextSize, const EncryptionKey &encKey) {
+    //We need at least 5 bytes (iv + parity)
+    if (ciphertextSize < 5) {
+      return boost::none;
+    }
+
+    //Check parity
+    int32_t expectedParity = _parity(ciphertext, plaintextSize(ciphertextSize) + 1);
+    int32_t actualParity = *(int32_t*)(ciphertext + plaintextSize(ciphertextSize) + 1);
+    if (expectedParity != actualParity) {
+      return boost::none;
+    }
+
+    //Decrypt caesar chiffre from ciphertext
+    int32_t iv = *(int32_t*)ciphertext;
+    cpputils::Data result(plaintextSize(ciphertextSize));
+    _caesar((byte*)result.data(), ciphertext + 1, plaintextSize(ciphertextSize), -(encKey.value+iv));
+    return std::move(result);
+  }
+
+private:
+  static int32_t _parity(const byte *data, unsigned int size) {
+    int32_t parity = 34343435; // some init value
+    int32_t *intData = (int32_t*)data;
+    unsigned int intSize = size / sizeof(int32_t);
+    for (unsigned int i = 0; i < intSize; ++i) {
+      parity += intData[i];
+    }
+    unsigned int remainingBytes = size - 4 * intSize;
+    for (unsigned int i = 0; i < remainingBytes; ++i) {
+      parity += (data[4*intSize + i] << (24 - 8*i));
+    }
+    return parity;
+  }
+
+  static void _caesar(byte *dst, const byte *src, unsigned int size, uint8_t key) {
+    for (unsigned int i = 0; i < size; ++i) {
+      dst[i] = src[i] + key;
+    }
+  }
+};
+
+#endif
diff --git a/test/implementations/ondisk/OnDiskBlockStoreTest.cpp b/test/implementations/ondisk/OnDiskBlockStoreTest.cpp
index 1ee64b0e..884e5516 100644
--- a/test/implementations/ondisk/OnDiskBlockStoreTest.cpp
+++ b/test/implementations/ondisk/OnDiskBlockStoreTest.cpp
@@ -4,7 +4,7 @@
 #include "../../testutils/BlockStoreWithRandomKeysTest.h"
 #include "google/gtest/gtest.h"
 
-#include "messmer/tempfile/src/TempDir.h"
+#include "messmer/cpp-utils/tempfile/TempDir.h"
 
 
 using blockstore::BlockStore;
@@ -14,7 +14,7 @@ using blockstore::ondisk::OnDiskBlockStore;
 using std::unique_ptr;
 using std::make_unique;
 
-using tempfile::TempDir;
+using cpputils::TempDir;
 
 class OnDiskBlockStoreTestFixture: public BlockStoreTestFixture {
 public:
diff --git a/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockCreateTest.cpp b/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockCreateTest.cpp
index 42663fde..89fe0bfa 100644
--- a/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockCreateTest.cpp
+++ b/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockCreateTest.cpp
@@ -1,18 +1,17 @@
-#include "../../../../implementations/ondisk/FileAlreadyExistsException.h"
 #include "../../../../implementations/ondisk/OnDiskBlock.h"
 #include "google/gtest/gtest.h"
 
-#include "messmer/tempfile/src/TempFile.h"
-#include "messmer/tempfile/src/TempDir.h"
+#include <messmer/cpp-utils/tempfile/TempFile.h>
+#include <messmer/cpp-utils/tempfile/TempDir.h>
 
 using ::testing::Test;
 using ::testing::WithParamInterface;
 using ::testing::Values;
 
-using tempfile::TempFile;
-using tempfile::TempDir;
-
 using std::unique_ptr;
+using cpputils::Data;
+using cpputils::TempFile;
+using cpputils::TempDir;
 
 using namespace blockstore;
 using namespace blockstore::ondisk;
@@ -63,13 +62,13 @@ public:
 INSTANTIATE_TEST_CASE_P(OnDiskBlockCreateSizeTest, OnDiskBlockCreateSizeTest, Values(0, 1, 5, 1024, 10*1024*1024));
 
 TEST_P(OnDiskBlockCreateSizeTest, OnDiskSizeIsCorrect) {
-  Data fileContent = Data::LoadFromFile(file.path());
+  Data fileContent = Data::LoadFromFile(file.path()).value();
   EXPECT_EQ(GetParam(), fileContent.size());
 }
 
 TEST_P(OnDiskBlockCreateSizeTest, OnDiskBlockIsZeroedOut) {
-  Data fileContent = Data::LoadFromFile(file.path());
-  EXPECT_EQ(0, std::memcmp(ZEROES.data(), fileContent.data(), fileContent.size()));
+  Data fileContent = Data::LoadFromFile(file.path()).value();
+  EXPECT_EQ(ZEROES, fileContent);
 }
 
 // This test is also tested by OnDiskBlockStoreTest, but there the block is created using the BlockStore interface.
diff --git a/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockFlushTest.cpp b/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockFlushTest.cpp
index d2877f0c..8d723b92 100644
--- a/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockFlushTest.cpp
+++ b/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockFlushTest.cpp
@@ -1,19 +1,19 @@
-#include "../../../../implementations/ondisk/FileAlreadyExistsException.h"
 #include "../../../../implementations/ondisk/OnDiskBlock.h"
-#include "../../../testutils/DataBlockFixture.h"
+#include <messmer/cpp-utils/data/DataFixture.h>
 #include "google/gtest/gtest.h"
 
-#include "messmer/tempfile/src/TempFile.h"
-#include "messmer/tempfile/src/TempDir.h"
+#include <messmer/cpp-utils/tempfile/TempFile.h>
+#include <messmer/cpp-utils/tempfile/TempDir.h>
 
 using ::testing::Test;
 using ::testing::WithParamInterface;
 using ::testing::Values;
 
-using tempfile::TempFile;
-using tempfile::TempDir;
-
 using std::unique_ptr;
+using cpputils::Data;
+using cpputils::DataFixture;
+using cpputils::TempFile;
+using cpputils::TempDir;
 
 using namespace blockstore;
 using namespace blockstore::ondisk;
@@ -27,27 +27,23 @@ public:
   : dir(),
     key(Key::FromString("1491BB4932A389EE14BC7090AC772972")),
     file(dir.path() / key.ToString(), false),
-    randomData(GetParam()) {
+    randomData(DataFixture::generate(GetParam())) {
   }
   TempDir dir;
   Key key;
   TempFile file;
 
-  DataBlockFixture randomData;
+  Data randomData;
 
   unique_ptr<OnDiskBlock> CreateBlockAndLoadItFromDisk() {
     {
-      Data data(randomData.size());
-      std::memcpy(data.data(), randomData.data(), randomData.size());
-      auto block = OnDiskBlock::CreateOnDisk(dir.path(), key, std::move(data));
+      OnDiskBlock::CreateOnDisk(dir.path(), key, randomData.copy());
     }
     return OnDiskBlock::LoadFromDisk(dir.path(), key);
   }
 
   unique_ptr<OnDiskBlock> CreateBlock() {
-	Data data(randomData.size());
-	std::memcpy(data.data(), randomData.data(), randomData.size());
-    return OnDiskBlock::CreateOnDisk(dir.path(), key, std::move(data));
+    return OnDiskBlock::CreateOnDisk(dir.path(), key, randomData.copy());
   }
 
   void WriteDataToBlock(const unique_ptr<OnDiskBlock> &block) {
@@ -60,9 +56,8 @@ public:
   }
 
   void EXPECT_STORED_FILE_DATA_CORRECT() {
-    Data actual = Data::LoadFromFile(file.path());
-    EXPECT_EQ(randomData.size(), actual.size());
-    EXPECT_EQ(0, std::memcmp(randomData.data(), actual.data(), randomData.size()));
+    Data actual = Data::LoadFromFile(file.path()).value();
+    EXPECT_EQ(randomData, actual);
   }
 };
 INSTANTIATE_TEST_CASE_P(OnDiskBlockFlushTest, OnDiskBlockFlushTest, Values((size_t)0, (size_t)1, (size_t)1024, (size_t)4096, (size_t)10*1024*1024));
diff --git a/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockLoadTest.cpp b/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockLoadTest.cpp
index 8a32794b..8fdf8ff6 100644
--- a/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockLoadTest.cpp
+++ b/test/implementations/ondisk/OnDiskBlockTest/OnDiskBlockLoadTest.cpp
@@ -1,23 +1,24 @@
 #include "../../../../implementations/ondisk/OnDiskBlock.h"
-#include "../../../testutils/DataBlockFixture.h"
+#include <messmer/cpp-utils/data/DataFixture.h>
 #include "../../../../utils/FileDoesntExistException.h"
 #include "google/gtest/gtest.h"
 
-#include "../../../../utils/Data.h"
-#include "messmer/tempfile/src/TempFile.h"
-#include "messmer/tempfile/src/TempDir.h"
+#include <messmer/cpp-utils/data/Data.h>
+#include <messmer/cpp-utils/tempfile/TempFile.h>
+#include <messmer/cpp-utils/tempfile/TempDir.h>
 #include <fstream>
 
 using ::testing::Test;
 using ::testing::WithParamInterface;
 using ::testing::Values;
 
-using tempfile::TempFile;
-using tempfile::TempDir;
-
 using std::ofstream;
 using std::unique_ptr;
 using std::ios;
+using cpputils::Data;
+using cpputils::DataFixture;
+using cpputils::TempFile;
+using cpputils::TempDir;
 
 using namespace blockstore;
 using namespace blockstore::ondisk;
@@ -40,18 +41,15 @@ public:
     data.StoreToFile(file.path());
   }
 
-  void StoreData(const DataBlockFixture &data) {
-    //TODO Implement data.StoreToFile(filepath) instead
-    Data dataobj(data.size());
-    std::memcpy(dataobj.data(), data.data(), data.size());
-    dataobj.StoreToFile(file.path());
+  void StoreData(const Data &data) {
+    data.StoreToFile(file.path());
   }
 
   unique_ptr<OnDiskBlock> LoadBlock() {
     return OnDiskBlock::LoadFromDisk(dir.path(), key);
   }
 
-  void EXPECT_BLOCK_DATA_EQ(const DataBlockFixture &expected, const OnDiskBlock &actual) {
+  void EXPECT_BLOCK_DATA_EQ(const Data &expected, const OnDiskBlock &actual) {
     EXPECT_EQ(expected.size(), actual.size());
     EXPECT_EQ(0, std::memcmp(expected.data(), actual.data(), expected.size()));
   }
@@ -67,7 +65,7 @@ TEST_P(OnDiskBlockLoadTest, FileSizeIsCorrect) {
 }
 
 TEST_P(OnDiskBlockLoadTest, LoadedDataIsCorrect) {
-  DataBlockFixture randomData(GetParam());
+  Data randomData = DataFixture::generate(GetParam());
   StoreData(randomData);
 
   auto block = LoadBlock();
diff --git a/test/interface/helpers/BlockStoreWithRandomKeysTest.cpp b/test/interface/helpers/BlockStoreWithRandomKeysTest.cpp
index fa0109a6..fdcfada0 100644
--- a/test/interface/helpers/BlockStoreWithRandomKeysTest.cpp
+++ b/test/interface/helpers/BlockStoreWithRandomKeysTest.cpp
@@ -1,7 +1,7 @@
 #include "../../../interface/helpers/BlockStoreWithRandomKeys.h"
 #include "google/gtest/gtest.h"
 #include "google/gmock/gmock.h"
-#include "../../testutils/DataBlockFixture.h"
+#include <messmer/cpp-utils/data/DataFixture.h>
 
 using ::testing::Test;
 using ::testing::_;
@@ -13,6 +13,8 @@ using ::testing::ByRef;
 using std::string;
 using std::unique_ptr;
 using std::make_unique;
+using cpputils::Data;
+using cpputils::DataFixture;
 
 using namespace blockstore;
 
@@ -26,7 +28,7 @@ public:
     return unique_ptr<Block>(do_load(key));
   }
   MOCK_METHOD1(do_load, Block*(const Key &));
-  void remove(unique_ptr<Block> block) {}
+  void remove(unique_ptr<Block> block) {UNUSED(block);}
   MOCK_CONST_METHOD0(numBlocks, uint64_t());
 };
 
@@ -47,7 +49,7 @@ public:
   const blockstore::Key key = Key::FromString("1491BB4932A389EE14BC7090AC772972");
 
   Data createDataWithSize(size_t size) {
-	DataBlockFixture fixture(size);
+	Data fixture(DataFixture::generate(size));
 	Data data(size);
 	std::memcpy(data.data(), fixture.data(), size);
 	return data;
diff --git a/test/testutils/BlockStoreTest.h b/test/testutils/BlockStoreTest.h
index ad7d940c..f97eb4d5 100644
--- a/test/testutils/BlockStoreTest.h
+++ b/test/testutils/BlockStoreTest.h
@@ -4,8 +4,6 @@
 
 #include "google/gtest/gtest.h"
 
-#include "DataBlockFixture.h"
-
 #include "../../interface/BlockStore.h"
 
 class BlockStoreTestFixture {
@@ -28,14 +26,14 @@ TYPED_TEST_CASE_P(BlockStoreTest);
 
 TYPED_TEST_P(BlockStoreTest, TwoCreatedBlocksHaveDifferentKeys) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block1 = blockStore->create(blockstore::Data(1024));
-  auto block2 = blockStore->create(blockstore::Data(1024));
+  auto block1 = blockStore->create(cpputils::Data(1024));
+  auto block2 = blockStore->create(cpputils::Data(1024));
   EXPECT_NE(block1->key(), block2->key());
 }
 
 TYPED_TEST_P(BlockStoreTest, BlockIsNotLoadableAfterDeleting) {
   auto blockStore = this->fixture.createBlockStore();
-  auto blockkey = blockStore->create(blockstore::Data(1024))->key();
+  auto blockkey = blockStore->create(cpputils::Data(1024))->key();
   auto block = blockStore->load(blockkey);
   EXPECT_NE(nullptr, block.get());
   blockStore->remove(std::move(block));
@@ -49,55 +47,55 @@ TYPED_TEST_P(BlockStoreTest, NumBlocksIsCorrectOnEmptyBlockstore) {
 
 TYPED_TEST_P(BlockStoreTest, NumBlocksIsCorrectAfterAddingOneBlock) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block = blockStore->create(blockstore::Data(1));
+  auto block = blockStore->create(cpputils::Data(1));
   EXPECT_EQ(1, blockStore->numBlocks());
 }
 
 TYPED_TEST_P(BlockStoreTest, NumBlocksIsCorrectAfterAddingOneBlock_AfterClosingBlock) {
   auto blockStore = this->fixture.createBlockStore();
-  blockStore->create(blockstore::Data(1));
+  blockStore->create(cpputils::Data(1));
   EXPECT_EQ(1, blockStore->numBlocks());
 }
 
 TYPED_TEST_P(BlockStoreTest, NumBlocksIsCorrectAfterRemovingTheLastBlock) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block = blockStore->create(blockstore::Data(1));
+  auto block = blockStore->create(cpputils::Data(1));
   blockStore->remove(std::move(block));
   EXPECT_EQ(0, blockStore->numBlocks());
 }
 
 TYPED_TEST_P(BlockStoreTest, NumBlocksIsCorrectAfterAddingTwoBlocks) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block1 = blockStore->create(blockstore::Data(1));
-  auto block2 = blockStore->create(blockstore::Data(0));
+  auto block1 = blockStore->create(cpputils::Data(1));
+  auto block2 = blockStore->create(cpputils::Data(0));
   EXPECT_EQ(2, blockStore->numBlocks());
 }
 
 TYPED_TEST_P(BlockStoreTest, NumBlocksIsCorrectAfterAddingTwoBlocks_AfterClosingFirstBlock) {
   auto blockStore = this->fixture.createBlockStore();
-  blockStore->create(blockstore::Data(1));
-  auto block2 = blockStore->create(blockstore::Data(0));
+  blockStore->create(cpputils::Data(1));
+  auto block2 = blockStore->create(cpputils::Data(0));
   EXPECT_EQ(2, blockStore->numBlocks());
 }
 
 TYPED_TEST_P(BlockStoreTest, NumBlocksIsCorrectAfterAddingTwoBlocks_AfterClosingSecondBlock) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block1 = blockStore->create(blockstore::Data(1));
-  blockStore->create(blockstore::Data(0));
+  auto block1 = blockStore->create(cpputils::Data(1));
+  blockStore->create(cpputils::Data(0));
   EXPECT_EQ(2, blockStore->numBlocks());
 }
 
 TYPED_TEST_P(BlockStoreTest, NumBlocksIsCorrectAfterAddingTwoBlocks_AfterClosingBothBlocks) {
   auto blockStore = this->fixture.createBlockStore();
-  blockStore->create(blockstore::Data(1));
-  blockStore->create(blockstore::Data(0));
+  blockStore->create(cpputils::Data(1));
+  blockStore->create(cpputils::Data(0));
   EXPECT_EQ(2, blockStore->numBlocks());
 }
 
 TYPED_TEST_P(BlockStoreTest, NumBlocksIsCorrectAfterRemovingABlock) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block = blockStore->create(blockstore::Data(1));
-  blockStore->create(blockstore::Data(1));
+  auto block = blockStore->create(cpputils::Data(1));
+  blockStore->create(cpputils::Data(1));
   blockStore->remove(std::move(block));
   EXPECT_EQ(1, blockStore->numBlocks());
 }
diff --git a/test/testutils/BlockStoreTest_Data.h b/test/testutils/BlockStoreTest_Data.h
index 11dfa2ac..202c8b32 100644
--- a/test/testutils/BlockStoreTest_Data.h
+++ b/test/testutils/BlockStoreTest_Data.h
@@ -12,15 +12,12 @@ public:
   BlockStoreDataParametrizedTest(std::unique_ptr<blockstore::BlockStore> blockStore_, const DataRange &testData_)
     : blockStore(std::move(blockStore_)),
       testData(testData_),
-      foregroundData(testData.count), backgroundData(testData.blocksize) {
-    DataBlockFixture _foregroundData(testData.count);
-    DataBlockFixture _backgroundData(testData.blocksize);
-    std::memcpy(foregroundData.data(), _foregroundData.data(), foregroundData.size());
-    std::memcpy(backgroundData.data(), _backgroundData.data(), backgroundData.size());
+      foregroundData(cpputils::DataFixture::generate(testData.count, 0)),
+      backgroundData(cpputils::DataFixture::generate(testData.blocksize, 1)) {
   }
 
   void TestWriteAndReadImmediately() {
-    auto block = blockStore->create(blockstore::Data(testData.blocksize).FillWithZeroes());
+    auto block = blockStore->create(cpputils::Data(testData.blocksize).FillWithZeroes());
     block->write(foregroundData.data(), testData.offset, testData.count);
 
     EXPECT_DATA_READS_AS(foregroundData, *block, testData.offset, testData.count);
@@ -36,7 +33,7 @@ public:
   }
 
   void TestOverwriteAndRead() {
-    auto block = blockStore->create(blockstore::Data(testData.blocksize));
+    auto block = blockStore->create(cpputils::Data(testData.blocksize));
     block->write(backgroundData.data(), 0, testData.blocksize);
     block->write(foregroundData.data(), testData.offset, testData.count);
     EXPECT_DATA_READS_AS(foregroundData, *block, testData.offset, testData.count);
@@ -46,30 +43,25 @@ public:
 private:
   std::unique_ptr<blockstore::BlockStore> blockStore;
   DataRange testData;
-  blockstore::Data foregroundData;
-  blockstore::Data backgroundData;
+  cpputils::Data foregroundData;
+  cpputils::Data backgroundData;
 
-  void EXPECT_DATA_EQ(const blockstore::Data &expected, const blockstore::Data &actual) {
-    EXPECT_EQ(expected.size(), actual.size());
-    EXPECT_EQ(0, std::memcmp(expected.data(), actual.data(), expected.size()));
-  }
-
-  blockstore::Key CreateBlockWriteToItAndReturnKey(const blockstore::Data &to_write) {
-    auto newblock = blockStore->create(blockstore::Data(testData.blocksize).FillWithZeroes());
+  blockstore::Key CreateBlockWriteToItAndReturnKey(const cpputils::Data &to_write) {
+    auto newblock = blockStore->create(cpputils::Data(testData.blocksize).FillWithZeroes());
 
     newblock->write(to_write.data(), testData.offset, testData.count);
     return newblock->key();
   }
 
-  void EXPECT_DATA_READS_AS(const blockstore::Data &expected, const blockstore::Block &block, off_t offset, size_t count) {
-    blockstore::Data read(count);
+  void EXPECT_DATA_READS_AS(const cpputils::Data &expected, const blockstore::Block &block, off_t offset, size_t count) {
+    cpputils::Data read(count);
     std::memcpy(read.data(), (uint8_t*)block.data() + offset, count);
-    EXPECT_DATA_EQ(expected, read);
+    EXPECT_EQ(expected, read);
   }
 
-  void EXPECT_DATA_READS_AS_OUTSIDE_OF(const blockstore::Data &expected, const blockstore::Block &block, off_t start, size_t count) {
-    blockstore::Data begin(start);
-    blockstore::Data end(testData.blocksize - count - start);
+  void EXPECT_DATA_READS_AS_OUTSIDE_OF(const cpputils::Data &expected, const blockstore::Block &block, off_t start, size_t count) {
+    cpputils::Data begin(start);
+    cpputils::Data end(testData.blocksize - count - start);
 
     std::memcpy(begin.data(), expected.data(), start);
     std::memcpy(end.data(), (uint8_t*)expected.data()+start+count, end.size());
@@ -79,7 +71,7 @@ private:
   }
 
   void EXPECT_DATA_IS_ZEROES_OUTSIDE_OF(const blockstore::Block &block, off_t start, size_t count) {
-    blockstore::Data ZEROES(testData.blocksize);
+    cpputils::Data ZEROES(testData.blocksize);
     ZEROES.FillWithZeroes();
     EXPECT_DATA_READS_AS_OUTSIDE_OF(ZEROES, block, start, count);
   }
diff --git a/test/testutils/BlockStoreTest_Size.h b/test/testutils/BlockStoreTest_Size.h
index 5948d836..20ee3fbb 100644
--- a/test/testutils/BlockStoreTest_Size.h
+++ b/test/testutils/BlockStoreTest_Size.h
@@ -1,6 +1,7 @@
 // This file is meant to be included by BlockStoreTest.h only
 
-#include "../../utils/Data.h"
+#include <messmer/cpp-utils/data/Data.h>
+#include <messmer/cpp-utils/data/DataFixture.h>
 
 class BlockStoreSizeParameterizedTest {
 public:
@@ -18,39 +19,34 @@ public:
   }
 
   void TestCreatedBlockData() {
-	DataBlockFixture dataFixture(size);
-	blockstore::Data data(size);
-	std::memcpy(data.data(), dataFixture.data(), size);
-	auto block = blockStore->create(data);
-	EXPECT_EQ(0, std::memcmp(dataFixture.data(), block->data(), size));
-
+    cpputils::Data data = cpputils::DataFixture::generate(size);
+    auto block = blockStore->create(data);
+    EXPECT_EQ(0, std::memcmp(data.data(), block->data(), size));
   }
 
   void TestLoadingUnchangedBlockData() {
-	DataBlockFixture dataFixture(size);
-	blockstore::Data data(size);
-	std::memcpy(data.data(), dataFixture.data(), size);
-	blockstore::Key key = blockStore->create(data)->key();
+    cpputils::Data data = cpputils::DataFixture::generate(size);
+    blockstore::Key key = blockStore->create(data)->key();
     auto loaded_block = blockStore->load(key);
-    EXPECT_EQ(0, std::memcmp(dataFixture.data(), loaded_block->data(), size));
+    EXPECT_EQ(0, std::memcmp(data.data(), loaded_block->data(), size));
   }
 
   void TestLoadedBlockIsCorrect() {
-    DataBlockFixture randomData(size);
+    cpputils::Data randomData = cpputils::DataFixture::generate(size);
     auto loaded_block = StoreDataToBlockAndLoadIt(randomData);
     EXPECT_EQ(size, loaded_block->size());
     EXPECT_EQ(0, std::memcmp(randomData.data(), loaded_block->data(), size));
   }
 
   void TestLoadedBlockIsCorrectWhenLoadedDirectlyAfterFlushing() {
-    DataBlockFixture randomData(size);
+    cpputils::Data randomData = cpputils::DataFixture::generate(size);
     auto loaded_block = StoreDataToBlockAndLoadItDirectlyAfterFlushing(randomData);
     EXPECT_EQ(size, loaded_block->size());
     EXPECT_EQ(0, std::memcmp(randomData.data(), loaded_block->data(), size));
   }
 
   void TestAfterCreate_FlushingDoesntChangeBlock() {
-    DataBlockFixture randomData(size);
+    cpputils::Data randomData = cpputils::DataFixture::generate(size);
     auto block =  CreateBlock();
     WriteDataToBlock(block.get(), randomData);
     block->flush();
@@ -59,7 +55,7 @@ public:
   }
 
   void TestAfterLoad_FlushingDoesntChangeBlock() {
-    DataBlockFixture randomData(size);
+    cpputils::Data randomData = cpputils::DataFixture::generate(size);
     auto block =  CreateBlockAndLoadIt();
     WriteDataToBlock(block.get(), randomData);
     block->flush();
@@ -68,10 +64,10 @@ public:
   }
 
   void TestAfterCreate_FlushesWhenDestructed() {
-    DataBlockFixture randomData(size);
+    cpputils::Data randomData = cpputils::DataFixture::generate(size);
     blockstore::Key key = key;
     {
-      auto block = blockStore->create(blockstore::Data(size));
+      auto block = blockStore->create(cpputils::Data(size));
       key = block->key();
       WriteDataToBlock(block.get(), randomData);
     }
@@ -80,7 +76,7 @@ public:
   }
 
   void TestAfterLoad_FlushesWhenDestructed() {
-    DataBlockFixture randomData(size);
+    cpputils::Data randomData = cpputils::DataFixture::generate(size);
     blockstore::Key key = key;
     {
       key = CreateBlock()->key();
@@ -102,26 +98,22 @@ private:
   std::unique_ptr<blockstore::BlockStore> blockStore;
   size_t size;
 
-  blockstore::Data ZEROES(size_t size) {
-    blockstore::Data ZEROES(size);
+  cpputils::Data ZEROES(size_t size) {
+    cpputils::Data ZEROES(size);
     ZEROES.FillWithZeroes();
     return ZEROES;
   }
 
-  std::unique_ptr<blockstore::Block> StoreDataToBlockAndLoadIt(const DataBlockFixture &data) {
+  std::unique_ptr<blockstore::Block> StoreDataToBlockAndLoadIt(const cpputils::Data &data) {
     blockstore::Key key = StoreDataToBlockAndGetKey(data);
     return blockStore->load(key);
   }
 
-  blockstore::Key StoreDataToBlockAndGetKey(const DataBlockFixture &dataFixture) {
-	blockstore::Data data(dataFixture.size());
-	std::memcpy(data.data(), dataFixture.data(), dataFixture.size());
+  blockstore::Key StoreDataToBlockAndGetKey(const cpputils::Data &data) {
     return blockStore->create(data)->key();
   }
 
-  std::unique_ptr<blockstore::Block> StoreDataToBlockAndLoadItDirectlyAfterFlushing(const DataBlockFixture &dataFixture) {
-	blockstore::Data data(dataFixture.size());
-	std::memcpy(data.data(), dataFixture.data(), dataFixture.size());
+  std::unique_ptr<blockstore::Block> StoreDataToBlockAndLoadItDirectlyAfterFlushing(const cpputils::Data &data) {
     auto block = blockStore->create(data);
     block->flush();
     return blockStore->load(block->key());
@@ -133,14 +125,14 @@ private:
   }
 
   std::unique_ptr<blockstore::Block> CreateBlock() {
-    return blockStore->create(blockstore::Data(size));
+    return blockStore->create(cpputils::Data(size));
   }
 
-  void WriteDataToBlock(blockstore::Block *block, const DataBlockFixture &randomData) {
+  void WriteDataToBlock(blockstore::Block *block, const cpputils::Data &randomData) {
     block->write(randomData.data(), 0, randomData.size());
   }
 
-  void EXPECT_BLOCK_DATA_CORRECT(const blockstore::Block &block, const DataBlockFixture &randomData) {
+  void EXPECT_BLOCK_DATA_CORRECT(const blockstore::Block &block, const cpputils::Data &randomData) {
     EXPECT_EQ(randomData.size(), block.size());
     EXPECT_EQ(0, std::memcmp(randomData.data(), block.data(), randomData.size()));
   }
diff --git a/test/testutils/BlockStoreWithRandomKeysTest.h b/test/testutils/BlockStoreWithRandomKeysTest.h
index 03d64cab..3f2db103 100644
--- a/test/testutils/BlockStoreWithRandomKeysTest.h
+++ b/test/testutils/BlockStoreWithRandomKeysTest.h
@@ -3,7 +3,6 @@
 #define TEST_BLOCKSTORE_IMPLEMENTATIONS_TESTUTILS_BLOCKSTOREWITHRANDOMKEYSTEST_H_
 
 #include <google/gtest/gtest.h>
-#include "DataBlockFixture.h"
 
 #include "../../interface/BlockStore.h"
 
@@ -31,45 +30,45 @@ TYPED_TEST_CASE_P(BlockStoreWithRandomKeysTest);
 
 TYPED_TEST_P(BlockStoreWithRandomKeysTest, CreateTwoBlocksWithSameKeyAndSameSize) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block = blockStore->tryCreate(this->key, blockstore::Data(1024));
+  auto block = blockStore->tryCreate(this->key, cpputils::Data(1024));
   block->flush();
-  auto block2 = blockStore->tryCreate(this->key, blockstore::Data(1024));
+  auto block2 = blockStore->tryCreate(this->key, cpputils::Data(1024));
   EXPECT_TRUE((bool)block);
   EXPECT_FALSE((bool)block2);
 }
 
 TYPED_TEST_P(BlockStoreWithRandomKeysTest, CreateTwoBlocksWithSameKeyAndDifferentSize) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block = blockStore->tryCreate(this->key, blockstore::Data(1024));
+  auto block = blockStore->tryCreate(this->key, cpputils::Data(1024));
   block->flush();
-  auto block2 = blockStore->tryCreate(this->key, blockstore::Data(4096));
+  auto block2 = blockStore->tryCreate(this->key, cpputils::Data(4096));
   EXPECT_TRUE((bool)block);
   EXPECT_FALSE((bool)block2);
 }
 
 TYPED_TEST_P(BlockStoreWithRandomKeysTest, CreateTwoBlocksWithSameKeyAndFirstNullSize) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block = blockStore->tryCreate(this->key, blockstore::Data(0));
+  auto block = blockStore->tryCreate(this->key, cpputils::Data(0));
   block->flush();
-  auto block2 = blockStore->tryCreate(this->key, blockstore::Data(1024));
+  auto block2 = blockStore->tryCreate(this->key, cpputils::Data(1024));
   EXPECT_TRUE((bool)block);
   EXPECT_FALSE((bool)block2);
 }
 
 TYPED_TEST_P(BlockStoreWithRandomKeysTest, CreateTwoBlocksWithSameKeyAndSecondNullSize) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block = blockStore->tryCreate(this->key, blockstore::Data(1024));
+  auto block = blockStore->tryCreate(this->key, cpputils::Data(1024));
   block->flush();
-  auto block2 = blockStore->tryCreate(this->key, blockstore::Data(0));
+  auto block2 = blockStore->tryCreate(this->key, cpputils::Data(0));
   EXPECT_TRUE((bool)block);
   EXPECT_FALSE((bool)block2);
 }
 
 TYPED_TEST_P(BlockStoreWithRandomKeysTest, CreateTwoBlocksWithSameKeyAndBothNullSize) {
   auto blockStore = this->fixture.createBlockStore();
-  auto block = blockStore->tryCreate(this->key, blockstore::Data(0));
+  auto block = blockStore->tryCreate(this->key, cpputils::Data(0));
   block->flush();
-  auto block2 = blockStore->tryCreate(this->key, blockstore::Data(0));
+  auto block2 = blockStore->tryCreate(this->key, cpputils::Data(0));
   EXPECT_TRUE((bool)block);
   EXPECT_FALSE((bool)block2);
 }
diff --git a/test/testutils/DataBlockFixture.cpp b/test/testutils/DataBlockFixture.cpp
deleted file mode 100644
index 252015b2..00000000
--- a/test/testutils/DataBlockFixture.cpp
+++ /dev/null
@@ -1,87 +0,0 @@
-#include "DataBlockFixture.h"
-#include <algorithm>
-#include <cstring>
-
-using std::min;
-
-DataBlockFixture::DataBlockFixture(size_t size, long long int IV): _fileData(new char[size]), _size(size) {
-  fillFileWithRandomData(IV);
-}
-
-DataBlockFixture::~DataBlockFixture() {
-  delete[] _fileData;
-}
-
-void DataBlockFixture::fillFileWithRandomData(long long int IV) {
-  long long int val = IV;
-  for(size_t i=0; i<_size/sizeof(long long int); ++i) {
-    //MMIX linear congruential generator
-    val *= 6364136223846793005L;
-    val += 1442695040888963407;
-    reinterpret_cast<long long int*>(_fileData)[i] = val;
-  }
-  uint64_t alreadyWritten = (_size/sizeof(long long int))*sizeof(long long int);
-  val *= 6364136223846793005L;
-  val += 1442695040888963407;
-  char *remainingBytes = reinterpret_cast<char*>(&val);
-  //Fill remaining bytes
-  for(size_t i=0; i<_size-alreadyWritten; ++i) {
-    reinterpret_cast<char*>(_fileData)[alreadyWritten + i] = remainingBytes[i];
-  }
-}
-
-const char *DataBlockFixture::data() const {
-  return _fileData;
-}
-
-int DataBlockFixture::read(void *buf, size_t count, off_t offset) {
-  size_t realCount = min(count, _size - offset);
-  memcpy(buf, _fileData+offset, realCount);
-  return realCount;
-}
-
-size_t DataBlockFixture::size() const {
-  return _size;
-}
-
-bool DataBlockFixture::fileContentEqual(const char *content, size_t count, off_t offset) {
-  return 0 == memcmp(content, _fileData + offset, count);
-}
-
-DataBlockFixtureWriteable::DataBlockFixtureWriteable(size_t size, long long int IV)
-  :DataBlockFixture(size, IV), _originalSize(size) {
-  _originalFileData = new char[size];
-  memcpy(_originalFileData, _fileData, size);
-}
-
-DataBlockFixtureWriteable::~DataBlockFixtureWriteable() {
-  delete[] _originalFileData;
-}
-
-void DataBlockFixtureWriteable::write(const void *buf, size_t count, off_t offset) {
-  extendFileSizeIfNecessary(count + offset);
-
-  memcpy(_fileData+offset, buf, count);
-}
-
-void DataBlockFixtureWriteable::extendFileSizeIfNecessary(size_t size) {
-  if (size > _size) {
-    extendFileSize(size);
-  }
-}
-
-void DataBlockFixtureWriteable::extendFileSize(size_t size) {
-  char *newfile = new char[size];
-  memcpy(newfile, _fileData, _size);
-  delete[] _fileData;
-  _fileData = newfile;
-  _size = size;
-}
-
-bool DataBlockFixtureWriteable::sizeUnchanged() {
-  return _size == _originalSize;
-}
-
-bool DataBlockFixtureWriteable::regionUnchanged(off_t offset, size_t count) {
-  return 0 == memcmp(_fileData+offset, _originalFileData+offset, count);
-}
diff --git a/test/testutils/DataBlockFixture.h b/test/testutils/DataBlockFixture.h
deleted file mode 100644
index 73d763d9..00000000
--- a/test/testutils/DataBlockFixture.h
+++ /dev/null
@@ -1,47 +0,0 @@
-#pragma once
-#ifndef TEST_TESTUTILS_DATABLOCKFIXTURE_H_
-#define TEST_TESTUTILS_DATABLOCKFIXTURE_H_
-
-#include <cstdio>
-
-class DataBlockFixture {
-public:
-  DataBlockFixture(size_t size, long long int IV = 1);
-  virtual ~DataBlockFixture();
-
-  int read(void *buf, size_t count, off_t offset);
-
-  // Return true, iff the given data is equal to the data of the file at the given offset.
-  bool fileContentEqual(const char *content, size_t count, off_t offset);
-
-  const char *data() const;
-
-  size_t size() const;
-
-protected:
-  char *_fileData;
-  size_t _size;
-
-private:
-  void fillFileWithRandomData(long long int IV);
-};
-
-class DataBlockFixtureWriteable: public DataBlockFixture {
-public:
-  DataBlockFixtureWriteable(size_t size, long long int IV = 1);
-  virtual ~DataBlockFixtureWriteable();
-
-  void write(const void *buf, size_t count, off_t offset);
-
-  bool sizeUnchanged();
-  bool regionUnchanged(off_t offset, size_t count);
-
-private:
-  void extendFileSizeIfNecessary(size_t size);
-  void extendFileSize(size_t size);
-
-  char *_originalFileData;
-  size_t _originalSize;
-};
-
-#endif
diff --git a/test/utils/BlockStoreUtilsTest.cpp b/test/utils/BlockStoreUtilsTest.cpp
index 93515636..adc72ad8 100644
--- a/test/utils/BlockStoreUtilsTest.cpp
+++ b/test/utils/BlockStoreUtilsTest.cpp
@@ -1,5 +1,5 @@
 #include "../../implementations/testfake/FakeBlockStore.h"
-#include "../testutils/DataBlockFixture.h"
+#include <messmer/cpp-utils/data/DataFixture.h>
 #include "../../utils/BlockStoreUtils.h"
 #include "google/gtest/gtest.h"
 
@@ -11,6 +11,8 @@ using ::testing::Values;
 
 using std::make_unique;
 using std::unique_ptr;
+using cpputils::Data;
+using cpputils::DataFixture;
 
 using namespace blockstore;
 using namespace blockstore::utils;
@@ -22,13 +24,13 @@ public:
   unsigned int SIZE = 1024 * 1024;
   BlockStoreUtilsTest():
     ZEROES(SIZE),
-    dataFixture(SIZE),
+    dataFixture(DataFixture::generate(SIZE)),
     blockStore(make_unique<FakeBlockStore>()) {
     ZEROES.FillWithZeroes();
   }
 
   Data ZEROES;
-  DataBlockFixture dataFixture;
+  Data dataFixture;
   unique_ptr<BlockStore> blockStore;
 };
 
diff --git a/test/utils/DataTest.cpp b/test/utils/DataTest.cpp
deleted file mode 100644
index 3601745a..00000000
--- a/test/utils/DataTest.cpp
+++ /dev/null
@@ -1,170 +0,0 @@
-#include "../testutils/DataBlockFixture.h"
-#include "../../utils/Data.h"
-#include "../../utils/FileDoesntExistException.h"
-#include "google/gtest/gtest.h"
-
-#include "messmer/tempfile/src/TempFile.h"
-
-#include <fstream>
-
-using ::testing::Test;
-using ::testing::WithParamInterface;
-using ::testing::Values;
-
-using tempfile::TempFile;
-
-using std::ifstream;
-using std::ofstream;
-
-namespace bf = boost::filesystem;
-
-using namespace blockstore;
-
-class DataTest: public Test {
-public:
-  bool DataIsZeroes(const Data &data) {
-    for (size_t i = 0; i != data.size(); ++ i) {
-      if (((char*)data.data())[i] != 0) {
-        return false;
-      }
-    }
-    return true;
-  }
-
-  void FillData(const DataBlockFixture &fillData, Data *data) {
-    ASSERT_EQ(fillData.size(), data->size());
-    std::memcpy(data->data(), fillData.data(), fillData.size());
-  }
-
-  void EXPECT_DATA_CORRECT(const DataBlockFixture &expectedData, const Data &data) {
-    ASSERT_EQ(expectedData.size(), data.size());
-    EXPECT_EQ(0, std::memcmp(expectedData.data(), data.data(), expectedData.size()));
-  }
-};
-
-class DataTestWithSizeParam: public DataTest, public WithParamInterface<size_t> {
-public:
-  DataBlockFixture randomData;
-
-  DataTestWithSizeParam(): randomData(GetParam()) {}
-
-  void FillData(Data *data) {
-    DataTest::FillData(randomData, data);
-  }
-
-  void StoreData(const bf::path &filepath) {
-    ofstream file(filepath.c_str(), std::ios::binary | std::ios::trunc);
-    file.write(randomData.data(), randomData.size());
-  }
-
-  void EXPECT_STORED_FILE_DATA_CORRECT(const bf::path &filepath) {
-    EXPECT_EQ(randomData.size(), bf::file_size(filepath));
-
-    ifstream file(filepath.c_str(), std::ios::binary);
-    char *read_data = new char[randomData.size()];
-    file.read(read_data, randomData.size());
-
-    EXPECT_EQ(0, std::memcmp(randomData.data(), read_data, randomData.size()));
-    delete[] read_data;
-  }
-
-  void EXPECT_DATA_CORRECT(const Data &data) {
-    DataTest::EXPECT_DATA_CORRECT(randomData, data);
-  }
-};
-
-INSTANTIATE_TEST_CASE_P(DataTestWithSizeParam, DataTestWithSizeParam, Values(0, 1, 2, 1024, 4096, 10*1024*1024));
-
-// Working on a large data area without a crash is a good indicator that we
-// are actually working on memory that was validly allocated for us.
-TEST_P(DataTestWithSizeParam, WriteAndCheck) {
-  Data data(GetParam());
-
-  FillData(&data);
-  EXPECT_DATA_CORRECT(data);
-}
-
-TEST_P(DataTestWithSizeParam, Size) {
-  Data data(GetParam());
-  EXPECT_EQ(GetParam(), data.size());
-}
-
-TEST_P(DataTestWithSizeParam, CheckStoredFile) {
-  Data data(GetParam());
-  FillData(&data);
-
-  TempFile file;
-  data.StoreToFile(file.path());
-
-  EXPECT_STORED_FILE_DATA_CORRECT(file.path());
-}
-
-TEST_P(DataTestWithSizeParam, CheckLoadedData) {
-  TempFile file;
-  StoreData(file.path());
-
-  Data data = Data::LoadFromFile(file.path());
-
-  EXPECT_DATA_CORRECT(data);
-}
-
-TEST_P(DataTestWithSizeParam, StoreDoesntChangeData) {
-  Data data(GetParam());
-  FillData(&data);
-
-  TempFile file;
-  data.StoreToFile(file.path());
-
-  EXPECT_DATA_CORRECT(data);
-}
-
-TEST_P(DataTestWithSizeParam, StoreAndLoad) {
-  Data data(GetParam());
-  FillData(&data);
-
-  TempFile file;
-  data.StoreToFile(file.path());
-  Data loaded_data = Data::LoadFromFile(file.path());
-
-  EXPECT_DATA_CORRECT(loaded_data);
-}
-
-TEST_P(DataTestWithSizeParam, Copy) {
-  Data data(GetParam());
-  FillData(&data);
-
-  Data copy = data.copy();
-
-  EXPECT_DATA_CORRECT(copy);
-}
-
-TEST_F(DataTest, InitializeWithZeroes) {
-  Data data(10*1024);
-  data.FillWithZeroes();
-  EXPECT_TRUE(DataIsZeroes(data));
-}
-
-TEST_F(DataTest, FillModifiedDataWithZeroes) {
-  Data data(10*1024);
-  DataBlockFixture randomData(10*1024);
-  FillData(randomData, &data);
-  EXPECT_FALSE(DataIsZeroes(data));
-
-  data.FillWithZeroes();
-  EXPECT_TRUE(DataIsZeroes(data));
-}
-
-//Needs 64bit for representation. This value isn't in the size param list, because the list is also used for read/write checks.
-TEST_F(DataTest, LargesizeSize) {
-  size_t size = 10L*1024*1024*1024;
-  Data data(size);
-  EXPECT_EQ(size, data.size());
-}
-
-TEST_F(DataTest, LoadingNonexistingFile) {
-  TempFile file(false); // Pass false to constructor, so the tempfile is not created
-  EXPECT_THROW(
-    Data::LoadFromFile(file.path()),
-    FileDoesntExistException
-  );
-}
diff --git a/test/utils/KeyTest.cpp b/test/utils/KeyTest.cpp
deleted file mode 100644
index aa78d1ec..00000000
--- a/test/utils/KeyTest.cpp
+++ /dev/null
@@ -1,144 +0,0 @@
-#include "../testutils/DataBlockFixture.h"
-#include "../../utils/Data.h"
-#include "../../utils/Key.h"
-#include "google/gtest/gtest.h"
-
-
-using ::testing::Test;
-using ::testing::WithParamInterface;
-using ::testing::Values;
-
-using std::string;
-
-using namespace blockstore;
-
-//TODO Test blockstore::FixedSizeData instead of blockstore::Key
-
-class KeyTest: public Test {
-public:
-  const string KEY1_AS_STRING = "1491BB4932A389EE14BC7090AC772972";
-  const string KEY2_AS_STRING = "272EE5517627CFA147A971A8E6E747E0";
-
-  const DataBlockFixture KEY3_AS_BINARY;
-  const DataBlockFixture KEY4_AS_BINARY;
-
-  KeyTest() : KEY3_AS_BINARY(Key::BINARY_LENGTH, 1), KEY4_AS_BINARY(Key::BINARY_LENGTH, 2) {}
-
-  void EXPECT_DATA_EQ(const DataBlockFixture &expected, const Data &actual) {
-    EXPECT_EQ(expected.size(), actual.size());
-    EXPECT_EQ(0, std::memcmp(expected.data(), actual.data(), expected.size()));
-  }
-};
-
-TEST_F(KeyTest, CanGenerateRandomKeysWithoutCrashing) {
-  Key result = Key::CreateRandom();
-}
-
-TEST_F(KeyTest, CreatedRandomKeysHaveCorrectLength) {
-  Key key = Key::CreateRandom();
-  EXPECT_EQ(Key::STRING_LENGTH, key.ToString().size());
-}
-
-TEST_F(KeyTest, EqualsTrue) {
-  Key key1_1 = Key::FromString(KEY1_AS_STRING);
-  Key key1_2 = Key::FromString(KEY1_AS_STRING);
-
-  EXPECT_TRUE(key1_1 == key1_2);
-  EXPECT_TRUE(key1_2 == key1_1);
-}
-
-TEST_F(KeyTest, EqualsFalse) {
-  Key key1_1 = Key::FromString(KEY1_AS_STRING);
-  Key key2_1 = Key::FromString(KEY2_AS_STRING);
-
-  EXPECT_FALSE(key1_1 == key2_1);
-  EXPECT_FALSE(key2_1 == key1_1);
-}
-
-TEST_F(KeyTest, NotEqualsFalse) {
-  Key key1_1 = Key::FromString(KEY1_AS_STRING);
-  Key key1_2 = Key::FromString(KEY1_AS_STRING);
-
-  EXPECT_FALSE(key1_1 != key1_2);
-  EXPECT_FALSE(key1_2 != key1_1);
-}
-
-TEST_F(KeyTest, NotEqualsTrue) {
-  Key key1_1 = Key::FromString(KEY1_AS_STRING);
-  Key key2_1 = Key::FromString(KEY2_AS_STRING);
-
-  EXPECT_TRUE(key1_1 != key2_1);
-  EXPECT_TRUE(key2_1 != key1_1);
-}
-
-class KeyTestWithStringKeyParam: public KeyTest, public WithParamInterface<string> {};
-INSTANTIATE_TEST_CASE_P(KeyTestWithStringKeyParam, KeyTestWithStringKeyParam, Values("2898B4B8A13CA63CBE0F0278CCE465DB", "6FFEBAD90C0DAA2B79628F0627CE9841"));
-
-TEST_P(KeyTestWithStringKeyParam, FromAndToString) {
-  Key key = Key::FromString(GetParam());
-  EXPECT_EQ(GetParam(), key.ToString());
-}
-
-TEST_P(KeyTestWithStringKeyParam, ToAndFromString) {
-  Key key = Key::FromString(GetParam());
-  Key key2 = Key::FromString(key.ToString());
-  EXPECT_EQ(key, key2);
-}
-
-class KeyTestWithBinaryKeyParam: public KeyTest, public WithParamInterface<const DataBlockFixture*> {
-public:
-  static const DataBlockFixture VALUE1;
-  static const DataBlockFixture VALUE2;
-};
-const DataBlockFixture KeyTestWithBinaryKeyParam::VALUE1(Key::BINARY_LENGTH, 3);
-const DataBlockFixture KeyTestWithBinaryKeyParam::VALUE2(Key::BINARY_LENGTH, 4);
-INSTANTIATE_TEST_CASE_P(KeyTestWithBinaryKeyParam, KeyTestWithBinaryKeyParam, Values(&KeyTestWithBinaryKeyParam::VALUE1, &KeyTestWithBinaryKeyParam::VALUE2));
-
-TEST_P(KeyTestWithBinaryKeyParam, FromAndToBinary) {
-  Key key = Key::FromBinary((uint8_t*)GetParam()->data());
-  Data keydata(Key::BINARY_LENGTH);
-  key.ToBinary(keydata.data());
-  EXPECT_DATA_EQ(*GetParam(), keydata);
-}
-
-TEST_P(KeyTestWithBinaryKeyParam, ToAndFromBinary) {
-  Key key = Key::FromBinary((uint8_t*)GetParam()->data());
-  Data stored(Key::BINARY_LENGTH);
-  key.ToBinary(stored.data());
-  Key loaded = Key::FromBinary(stored.data());
-  EXPECT_EQ(key, loaded);
-}
-
-class KeyTestWithKeyParam: public KeyTest, public WithParamInterface<Key> {};
-INSTANTIATE_TEST_CASE_P(KeyTestWithKeyParam, KeyTestWithKeyParam, Values(Key::FromString("2898B4B8A13CA63CBE0F0278CCE465DB"), Key::FromString("6FFEBAD90C0DAA2B79628F0627CE9841")));
-
-TEST_P(KeyTestWithKeyParam, CopyConstructor) {
-  Key copy(GetParam());
-  EXPECT_EQ(GetParam(), copy);
-}
-
-TEST_F(KeyTest, CopyConstructorDoesntChangeSource) {
-  Key key1 = Key::FromString(KEY1_AS_STRING);
-  Key key2(key1);
-  EXPECT_EQ(KEY1_AS_STRING, key1.ToString());
-}
-
-TEST_P(KeyTestWithKeyParam, IsEqualAfterAssignment1) {
-  Key key2 = Key::FromString(KEY2_AS_STRING);
-  EXPECT_NE(GetParam(), key2);
-  key2 = GetParam();
-  EXPECT_EQ(GetParam(), key2);
-}
-
-TEST_F(KeyTest, AssignmentDoesntChangeSource) {
-  Key key1 = Key::FromString(KEY1_AS_STRING);
-  Key key2 = Key::FromString(KEY2_AS_STRING);
-  key2 = key1;
-  EXPECT_EQ(KEY1_AS_STRING, key1.ToString());
-}
-
-// This tests that a Key object is very lightweight
-// (we will often pass keys around)
-TEST_F(KeyTest, KeyIsLightweightObject) {
-  EXPECT_EQ(Key::BINARY_LENGTH, sizeof(Key));
-}
diff --git a/utils/BlockStoreUtils.cpp b/utils/BlockStoreUtils.cpp
index e6c33e2c..2b20cdef 100644
--- a/utils/BlockStoreUtils.cpp
+++ b/utils/BlockStoreUtils.cpp
@@ -1,10 +1,11 @@
 #include "../interface/BlockStore.h"
 #include "BlockStoreUtils.h"
-#include "Data.h"
+#include <messmer/cpp-utils/data/Data.h>
 #include <memory>
 #include <cassert>
 
 using std::unique_ptr;
+using cpputils::Data;
 
 namespace blockstore {
 namespace utils {
diff --git a/utils/Data.cpp b/utils/Data.cpp
deleted file mode 100644
index 4895f727..00000000
--- a/utils/Data.cpp
+++ /dev/null
@@ -1,100 +0,0 @@
-#include "Data.h"
-#include "FileDoesntExistException.h"
-#include <stdexcept>
-#include <fstream>
-
-using std::istream;
-using std::ofstream;
-using std::ifstream;
-using std::ios;
-using std::unique_ptr;
-using std::make_unique;
-
-namespace bf = boost::filesystem;
-
-namespace blockstore {
-
-Data::Data(size_t size)
-: _size(size), _data(std::malloc(size)) {
-  if (nullptr == _data) {
-    throw std::bad_alloc();
-  }
-}
-
-Data::Data(Data &&rhs)
-: _size(rhs._size), _data(rhs._data) {
-  // Make rhs invalid, so the memory doesn't get freed in its destructor.
-  rhs._data = nullptr;
-}
-
-Data::~Data() {
-  std::free(_data);
-  _data = nullptr;
-}
-
-Data Data::copy() const {
-  Data copy(_size);
-  std::memcpy(copy._data, _data, _size);
-  return copy;
-}
-
-void *Data::data() {
-  return const_cast<void*>(const_cast<const Data*>(this)->data());
-}
-
-const void *Data::data() const {
-  return _data;
-}
-
-size_t Data::size() const {
-  return _size;
-}
-
-Data &Data::FillWithZeroes() {
-  std::memset(_data, 0, _size);
-  return *this;
-}
-
-void Data::StoreToFile(const bf::path &filepath) const {
-  ofstream file(filepath.c_str(), ios::binary | ios::trunc);
-  file.write((const char*)_data, _size);
-}
-
-Data Data::LoadFromFile(const bf::path &filepath) {
-  ifstream file(filepath.c_str(), ios::binary);
-  _assertFileExists(file, filepath);
-  size_t size = _getStreamSize(file);
-
-  Data result(size);
-  result._readFromStream(file);
-  return result;
-}
-
-void Data::_assertFileExists(const ifstream &file, const bf::path &filepath) {
-  if (!file.good()) {
-    throw FileDoesntExistException(filepath);
-  }
-}
-
-size_t Data::_getStreamSize(istream &stream) {
-  auto current_pos = stream.tellg();
-
-  //Retrieve length
-  stream.seekg(0, stream.end);
-  auto endpos = stream.tellg();
-
-  //Restore old position
-  stream.seekg(current_pos, stream.beg);
-
-  return endpos - current_pos;
-}
-
-void Data::_readFromStream(istream &stream) {
-  stream.read((char*)_data, _size);
-}
-
-bool operator==(const Data &lhs, const Data &rhs) {
-  return lhs.size() == rhs.size() && 0 == memcmp(lhs.data(), rhs.data(), lhs.size());
-}
-
-}
diff --git a/utils/Data.h b/utils/Data.h
deleted file mode 100644
index 54d5ccc7..00000000
--- a/utils/Data.h
+++ /dev/null
@@ -1,46 +0,0 @@
-#pragma once
-#ifndef BLOCKSTORE_IMPLEMENTATIONS_ONDISK_DATA_H_
-#define BLOCKSTORE_IMPLEMENTATIONS_ONDISK_DATA_H_
-
-#include <cstdlib>
-#include <boost/filesystem/path.hpp>
-#include <messmer/cpp-utils/macros.h>
-#include <memory>
-
-namespace blockstore {
-
-class Data {
-public:
-  explicit Data(size_t size);
-  Data(Data &&rhs); // move constructor
-  virtual ~Data();
-
-  Data copy() const;
-
-  void *data();
-  const void *data() const;
-
-  size_t size() const;
-
-  Data &FillWithZeroes();
-
-  void StoreToFile(const boost::filesystem::path &filepath) const;
-  static Data LoadFromFile(const boost::filesystem::path &filepath);
-
-private:
-  size_t _size;
-  void *_data;
-
-  static void _assertFileExists(const std::ifstream &file, const boost::filesystem::path &filepath);
-  static size_t _getStreamSize(std::istream &stream);
-  void _readFromStream(std::istream &stream);
-
-  DISALLOW_COPY_AND_ASSIGN(Data);
-};
-
-//TODO Test operator==
-bool operator==(const Data &lhs, const Data &rhs);
-
-}
-
-#endif
diff --git a/utils/FileDoesntExistException.h b/utils/FileDoesntExistException.h
index d4c0a521..9ae623db 100644
--- a/utils/FileDoesntExistException.h
+++ b/utils/FileDoesntExistException.h
@@ -10,7 +10,7 @@ namespace blockstore {
 
 class FileDoesntExistException: public std::runtime_error {
 public:
-  FileDoesntExistException(const boost::filesystem::path &filepath);
+  explicit FileDoesntExistException(const boost::filesystem::path &filepath);
   virtual ~FileDoesntExistException();
 };
 
diff --git a/utils/FixedSizeData.h b/utils/FixedSizeData.h
deleted file mode 100644
index f7b70f5c..00000000
--- a/utils/FixedSizeData.h
+++ /dev/null
@@ -1,112 +0,0 @@
-#pragma once
-#ifndef BLOCKSTORE_UTILS_data_H_
-#define BLOCKSTORE_UTILS_data_H_
-
-#include <cryptopp/cryptopp/hex.h>
-#include <cryptopp/cryptopp/osrng.h>
-#include <string>
-#include <cstring>
-
-namespace blockstore {
-
-template<int SIZE>
-class FixedSizeData {
-public:
-  //Non-virtual destructor because we want objects to be small
-  ~FixedSizeData() {}
-
-  static constexpr unsigned int BINARY_LENGTH = SIZE;
-  static constexpr unsigned int STRING_LENGTH = 2 * BINARY_LENGTH; // Hex encoding
-
-  static FixedSizeData<SIZE> CreateRandom();
-
-  static FixedSizeData<SIZE> FromString(const std::string &data);
-  std::string ToString() const;
-
-  static FixedSizeData<SIZE> FromBinary(const void *source);
-  void ToBinary(void *target) const;
-
-  const unsigned char *data() const;
-
-private:
-  FixedSizeData() {}
-  static CryptoPP::AutoSeededRandomPool &RandomPool();
-
-  unsigned char _data[BINARY_LENGTH];
-};
-
-template<int SIZE> bool operator==(const FixedSizeData<SIZE> &lhs, const FixedSizeData<SIZE> &rhs);
-template<int SIZE> bool operator!=(const FixedSizeData<SIZE> &lhs, const FixedSizeData<SIZE> &rhs);
-
-// ----- Implementation -----
-
-template<int SIZE> constexpr unsigned int FixedSizeData<SIZE>::BINARY_LENGTH;
-template<int SIZE> constexpr unsigned int FixedSizeData<SIZE>::STRING_LENGTH;
-
-template<int SIZE>
-CryptoPP::AutoSeededRandomPool &FixedSizeData<SIZE>::RandomPool() {
-  static CryptoPP::AutoSeededRandomPool singleton;
-  return singleton;
-}
-
-template<int SIZE>
-FixedSizeData<SIZE> FixedSizeData<SIZE>::CreateRandom() {
-  FixedSizeData<SIZE> result;
-  RandomPool().GenerateBlock(result._data, BINARY_LENGTH);
-  return result;
-}
-
-template<int SIZE>
-FixedSizeData<SIZE> FixedSizeData<SIZE>::FromString(const std::string &data) {
-  assert(data.size() == STRING_LENGTH);
-  FixedSizeData<SIZE> result;
-  CryptoPP::StringSource(data, true,
-    new CryptoPP::HexDecoder(
-      new CryptoPP::ArraySink(result._data, BINARY_LENGTH)
-    )
-  );
-  return result;
-}
-
-template<int SIZE>
-std::string FixedSizeData<SIZE>::ToString() const {
-  std::string result;
-  CryptoPP::ArraySource(_data, BINARY_LENGTH, true,
-    new CryptoPP::HexEncoder(
-      new CryptoPP::StringSink(result)
-    )
-  );
-  assert(result.size() == STRING_LENGTH);
-  return result;
-}
-
-template<int SIZE>
-const unsigned char *FixedSizeData<SIZE>::data() const {
-  return _data;
-}
-
-template<int SIZE>
-void FixedSizeData<SIZE>::ToBinary(void *target) const {
-  std::memcpy(target, _data, BINARY_LENGTH);
-}
-
-template<int SIZE>
-FixedSizeData<SIZE> FixedSizeData<SIZE>::FromBinary(const void *source) {
-  FixedSizeData<SIZE> result;
-  std::memcpy(result._data, source, BINARY_LENGTH);
-  return result;
-}
-
-template<int SIZE>
-bool operator==(const FixedSizeData<SIZE> &lhs, const FixedSizeData<SIZE> &rhs) {
-  return 0 == std::memcmp(lhs.data(), rhs.data(), FixedSizeData<SIZE>::BINARY_LENGTH);
-}
-
-template<int SIZE>
-bool operator!=(const FixedSizeData<SIZE> &lhs, const FixedSizeData<SIZE> &rhs) {
-  return !operator==(lhs, rhs);
-}
-
-}
-
-#endif
diff --git a/utils/Key.h b/utils/Key.h
index cd06ecda..e0b03f31 100644
--- a/utils/Key.h
+++ b/utils/Key.h
@@ -3,12 +3,12 @@
 #define BLOCKSTORE_UTILS_KEY_H_
 
 #include <string>
-#include "FixedSizeData.h"
+#include <messmer/cpp-utils/data/FixedSizeData.h>
 
 namespace blockstore {
 
 // A key here is NOT a key for encryption, but a key as used in key->value mappings ("access handle for a block").
-using Key = FixedSizeData<16>;
+using Key = cpputils::FixedSizeData<16>;
 
 }