cmac.h

// 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)

//! \class CMAC_Base
//! \brief CMAC base implementation
//! \since Crypto++ 5.6.0
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CMAC_Base : public MessageAuthenticationCode
{
public:
	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();}

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