vmac.h

Go to the documentation of this file.

// vmac.h - originally written and placed in the public domain by Wei Dai

/// \file vmac.h
/// \brief Classes for the VMAC message authentication code
/// \since Crypto++ 5.5

#ifndef CRYPTOPP_VMAC_H
#define CRYPTOPP_VMAC_H

#include "cryptlib.h"
#include "iterhash.h"
#include "seckey.h"

// Clang 3.3 integrated assembler crash on Linux. Clang 3.4 due to compiler
// error with .intel_syntax, http://llvm.org/bugs/show_bug.cgi?id=24232
#if CRYPTOPP_BOOL_X32 || defined(CRYPTOPP_DISABLE_MIXED_ASM)
# define CRYPTOPP_DISABLE_VMAC_ASM 1
#endif

NAMESPACE_BEGIN(CryptoPP)

/// \brief VMAC message authentication code base class
/// \since Crypto++ 5.5
class VMAC_Base : public IteratedHashBase<word64, MessageAuthenticationCode>
{
public:
    std::string AlgorithmName() const {return std::string("VMAC(") + GetCipher().AlgorithmName() + ")-" + IntToString(DigestSize()*8);}
    std::string AlgorithmProvider() const {return GetCipher().AlgorithmProvider();}
    unsigned int IVSize() const {return GetCipher().BlockSize();}
    unsigned int MinIVLength() const {return 1;}
    void Resynchronize(const byte *nonce, int length=-1);
    void GetNextIV(RandomNumberGenerator &rng, byte *IV);
    unsigned int DigestSize() const {return m_is128 ? 16 : 8;};
    void UncheckedSetKey(const byte *userKey, unsigned int keylength, const NameValuePairs &params);
    void TruncatedFinal(byte *mac, size_t size);
    unsigned int BlockSize() const {return m_L1KeyLength;}
    ByteOrder GetByteOrder() const {return LITTLE_ENDIAN_ORDER;}
    unsigned int OptimalDataAlignment() const;

protected:
    virtual BlockCipher & AccessCipher() =0;
    virtual int DefaultDigestSize() const =0;
    const BlockCipher & GetCipher() const {return const_cast<VMAC_Base *>(this)->AccessCipher();}
    void HashEndianCorrectedBlock(const word64 *data);
    size_t HashMultipleBlocks(const word64 *input, size_t length);
    void Init() {}
    word64* StateBuf() {return NULLPTR;}
    word64* DataBuf() {return (word64 *)(void*)m_data();}

    void VHASH_Update_SSE2(const word64 *data, size_t blocksRemainingInWord64, int tagPart);
    template <bool T_128BitTag>
        void VHASH_Update_Template(const word64 *data, size_t blockRemainingInWord128);
    void VHASH_Update(const word64 *data, size_t blocksRemainingInWord128);

    CRYPTOPP_BLOCK_1(polyState, word64, 4*(m_is128+1))
    CRYPTOPP_BLOCK_2(nhKey, word64, m_L1KeyLength/sizeof(word64) + 2*m_is128)
    CRYPTOPP_BLOCK_3(data, byte, m_L1KeyLength)
    CRYPTOPP_BLOCK_4(l3Key, word64, 2*(m_is128+1))
    CRYPTOPP_BLOCK_5(nonce, byte, IVSize())
    CRYPTOPP_BLOCK_6(pad, byte, IVSize())
    CRYPTOPP_BLOCKS_END(6)

    bool m_is128, m_padCached, m_isFirstBlock;
    unsigned int m_L1KeyLength;
};

/// \brief VMAC message authentication code
/// \tparam T_BlockCipher block cipher
/// \tparam T_DigestBitSize digest size, in bits
/// \details VMAC is a block cipher-based message authentication code algorithm
///   using a universal hash proposed by Ted Krovetz and Wei Dai in April 2007. The
///   algorithm was designed for high performance backed by a formal analysis.
/// \details The implementation is based on Ted Krovetz's public domain vmac.c
///   and <a href="http://tools.ietf.org/html/draft-krovetz-vmac-01">draft-krovetz-vmac-01.txt</a>.
/// \sa <a href="http://www.cryptolounge.org/wiki/VMAC">VMAC</a>.
/// \since Crypto++ 5.5
template <class T_BlockCipher, int T_DigestBitSize = 128>
class VMAC : public SimpleKeyingInterfaceImpl<VMAC_Base, SameKeyLengthAs<T_BlockCipher, SimpleKeyingInterface::UNIQUE_IV, T_BlockCipher::BLOCKSIZE> >
{
public:
    static std::string StaticAlgorithmName() {return std::string("VMAC(") + T_BlockCipher::StaticAlgorithmName() + ")-" + IntToString(T_DigestBitSize);}

private:
    BlockCipher & AccessCipher() {return m_cipher;}
    int DefaultDigestSize() const {return T_DigestBitSize/8;}
    typename T_BlockCipher::Encryption m_cipher;
};

NAMESPACE_END

#endif