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

/// \file

/// \brief Classes for CBC MAC

/// \since Crypto++ 3.1

#ifndef CRYPTOPP_CBCMAC_H

#define CRYPTOPP_CBCMAC_H

#include "seckey.h"

#include "secblock.h"

NAMESPACE_BEGIN(CryptoPP)

/// \brief CBC-MAC base class

/// \since Crypto++ 3.1

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_MAC_Base : public MessageAuthenticationCode

{

public:

  CBC_MAC_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 const_cast<CBC_MAC_Base*>(this)->AccessCipher().BlockSize();}

protected:

  virtual BlockCipher & AccessCipher() =0;

private:

  void ProcessBuf();

  SecByteBlock m_reg;

  unsigned int m_counter;

};

/// \brief CBC-MAC

/// \tparam T BlockCipherDocumentation derived class

/// \details CBC-MAC is compatible with FIPS 113. The MAC is secure only for fixed

///   length messages. For variable length messages use CMAC or DMAC.

/// \sa <a href="http://www.weidai.com/scan-mirror/mac.html#CBC-MAC">CBC-MAC</a>

/// \since Crypto++ 3.1

template <class T>

class CBC_MAC : public MessageAuthenticationCodeImpl<CBC_MAC_Base, CBC_MAC<T> >, public SameKeyLengthAs<T>

{

public:

  /// \brief Construct a CBC_MAC

  CBC_MAC() {}

  /// \brief Construct a CBC_MAC

  /// \param key a byte buffer used to key the cipher

  /// \param length the length of the byte buffer

  CBC_MAC(const byte *key, size_t length=SameKeyLengthAs<T>::DEFAULT_KEYLENGTH)

    {this->SetKey(key, length);}

  static std::string StaticAlgorithmName() {return std::string("CBC-MAC(") + T::StaticAlgorithmName() + ")";}

private:

  BlockCipher & AccessCipher() {return m_cipher;}

  typename T::Encryption m_cipher;

};

NAMESPACE_END

#endif