// 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"

/// \brief Enable CMAC and wide block ciphers

/// \details CMAC is only defined for AES. The library can support wide

///  block ciphers like Kaylna and Threefish since we know the polynomials.

#ifndef CRYPTOPP_CMAC_WIDE_BLOCK_CIPHERS

# define CRYPTOPP_CMAC_WIDE_BLOCK_CIPHERS 1

#endif  // CRYPTOPP_CMAC_WIDE_BLOCK_CIPHERS

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