cmac.h

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

/// \file cmac.h
/// \brief Classes for CMAC message authentication code
/// \since Crypto++ 5.6.0

#ifndef CRYPTOPP_CMAC_H
#define CRYPTOPP_CMAC_H

#include "seckey.h"
#include "secblock.h"

NAMESPACE_BEGIN(CryptoPP)

/// \brief CMAC base implementation
/// \since Crypto++ 5.6.0
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CMAC_Base : public MessageAuthenticationCode
{
public:

    virtual ~CMAC_Base() {}

    CMAC_Base() : m_counter(0) {}

    void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params);
    void Update(const byte *input, size_t length);
    void TruncatedFinal(byte *mac, size_t size);
    unsigned int DigestSize() const {return GetCipher().BlockSize();}
    unsigned int OptimalBlockSize() const {return GetCipher().BlockSize();}
    unsigned int OptimalDataAlignment() const {return GetCipher().OptimalDataAlignment();}
    std::string AlgorithmProvider() const {return GetCipher().AlgorithmProvider();}

protected:
    friend class EAX_Base;

    const BlockCipher & GetCipher() const {return const_cast<CMAC_Base*>(this)->AccessCipher();}
    virtual BlockCipher & AccessCipher() =0;

    void ProcessBuf();
    SecByteBlock m_reg;
    unsigned int m_counter;
};

/// \brief CMAC message authentication code
/// \tparam T block cipher
/// \details Template parameter T should be a class derived from BlockCipherDocumentation, for example AES, with a block size of 8, 16, or 32.
/// \sa <a href="http://www.cryptolounge.org/wiki/CMAC">CMAC</a>
/// \since Crypto++ 5.6.0
template <class T>
class CMAC : public MessageAuthenticationCodeImpl<CMAC_Base, CMAC<T> >, public SameKeyLengthAs<T>
{
public:
    /// \brief Construct a CMAC
    CMAC() {}
    /// \brief Construct a CMAC
    /// \param key the MAC key
    /// \param length the key size, in bytes
    CMAC(const byte *key, size_t length=SameKeyLengthAs<T>::DEFAULT_KEYLENGTH)
        {this->SetKey(key, length);}

    static std::string StaticAlgorithmName() {return std::string("CMAC(") + T::StaticAlgorithmName() + ")";}

private:
    BlockCipher & AccessCipher() {return m_cipher;}
    typename T::Encryption m_cipher;
};

NAMESPACE_END

#endif