diff --git a/interface/Blob.h b/interface/Blob.h
index 8466146c..97a26f2e 100644
--- a/interface/Blob.h
+++ b/interface/Blob.h
@@ -21,6 +21,9 @@ public:
   virtual uint64_t size() const = 0;
   virtual void resize(uint64_t numBytes) = 0;
 
+  virtual void read(void *target, uint64_t offset, uint64_t size) const = 0;
+  virtual void write(const void *source, uint64_t offset, uint64_t size) = 0;
+
   virtual void flush() const = 0;
 };