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Implemented AES256_GCM

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This commit is contained in:
Sebastian Messmer 2015-04-24 23:02:14 +02:00
parent 6e28af3105
commit 0335b243fb
3 changed files with 91 additions and 0 deletions
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49
implementations/encrypted/ciphers/AES256_GCM.cpp Normal file
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@ -0,0 +1,49 @@
#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;
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) {
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));
ArraySource((byte*)ciphertextData, ciphertextSize - IV_SIZE, true,
new AuthenticatedDecryptionFilter(decryption,
new ArraySink((byte*)plaintext.data(), plaintext.size())
)
);
return std::move(plaintext);
}
}
}

40
implementations/encrypted/ciphers/AES256_GCM.h Normal file
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#pragma once
#ifndef MESSMER_BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_CIPHERS_AES256_GCM_H_
#define MESSMER_BLOCKSTORE_IMPLEMENTATIONS_ENCRYPTED_CIPHERS_AES256_GCM_H_
#include "../../../utils/FixedSizeData.h"
#include "../../../utils/Data.h"
#include <cryptopp/cryptopp/aes.h>
#include <boost/optional.hpp>
#include "Cipher.h"
namespace blockstore {
namespace encrypted {
class AES256_GCM {
public:
BOOST_CONCEPT_ASSERT((CipherConcept<AES256_GCM>));
using EncryptionKey = 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 Data encrypt(const byte *plaintext, unsigned int plaintextSize, const EncryptionKey &encKey);
static boost::optional<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

2
test/implementations/encrypted/CipherTest.cpp
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@ -1,5 +1,6 @@
#include <google/gtest/gtest.h>
#include "../../../implementations/encrypted/ciphers/AES256_CFB.h"
#include "../../../implementations/encrypted/ciphers/AES256_GCM.h"
#include "../../../implementations/encrypted/ciphers/Cipher.h"
#include "../../testutils/DataBlockFixture.h"
@ -117,3 +118,4 @@ REGISTER_TYPED_TEST_CASE_P(CipherTest,
//TODO For authenticated ciphers, we need test cases checking that authentication fails on manipulations
INSTANTIATE_TYPED_TEST_CASE_P(AES256_CFB, CipherTest, AES256_CFB);
INSTANTIATE_TYPED_TEST_CASE_P(AES256_GCM, CipherTest, AES256_GCM);