/src/cryptopp/ccm.h

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

/// \file ccm.h
/// \brief CCM block cipher mode of operation
/// \since Crypto++ 5.6.0

#ifndef CRYPTOPP_CCM_H
#define CRYPTOPP_CCM_H

#include "authenc.h"
#include "modes.h"

NAMESPACE_BEGIN(CryptoPP)

/// \brief CCM block cipher base implementation
/// \details Base implementation of the AuthenticatedSymmetricCipher interface
/// \since Crypto++ 5.6.0
class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CCM_Base : public AuthenticatedSymmetricCipherBase
{
public:
  CCM_Base()
    : m_digestSize(0), m_L(0), m_messageLength(0), m_aadLength(0) {}

  // AuthenticatedSymmetricCipher
  std::string AlgorithmName() const
    {return GetBlockCipher().AlgorithmName() + std::string("/CCM");}
  std::string AlgorithmProvider() const
    {return GetBlockCipher().AlgorithmProvider();}
  size_t MinKeyLength() const
    {return GetBlockCipher().MinKeyLength();}
  size_t MaxKeyLength() const
    {return GetBlockCipher().MaxKeyLength();}
  size_t DefaultKeyLength() const
    {return GetBlockCipher().DefaultKeyLength();}
  size_t GetValidKeyLength(size_t keylength) const
    {return GetBlockCipher().GetValidKeyLength(keylength);}
  bool IsValidKeyLength(size_t keylength) const
    {return GetBlockCipher().IsValidKeyLength(keylength);}
  unsigned int OptimalDataAlignment() const
    {return GetBlockCipher().OptimalDataAlignment();}
  IV_Requirement IVRequirement() const
    {return UNIQUE_IV;}
  unsigned int IVSize() const
    {return 8;}
  unsigned int MinIVLength() const
    {return 7;}
  unsigned int MaxIVLength() const
    {return 13;}
  unsigned int DigestSize() const
    {return m_digestSize;}
  lword MaxHeaderLength() const
    {return W64LIT(0)-1;}
  lword MaxMessageLength() const
    {return m_L<8 ? (W64LIT(1)<<(8*m_L))-1 : W64LIT(0)-1;}
  bool NeedsPrespecifiedDataLengths() const
    {return true;}
  void UncheckedSpecifyDataLengths(lword headerLength, lword messageLength, lword footerLength);

protected:
  // AuthenticatedSymmetricCipherBase
  bool AuthenticationIsOnPlaintext() const
    {return true;}
  unsigned int AuthenticationBlockSize() const
    {return GetBlockCipher().BlockSize();}
  void SetKeyWithoutResync(const byte *userKey, size_t keylength, const NameValuePairs &params);
  void Resync(const byte *iv, size_t len);
  size_t AuthenticateBlocks(const byte *data, size_t len);
  void AuthenticateLastHeaderBlock();
  void AuthenticateLastConfidentialBlock();
  void AuthenticateLastFooterBlock(byte *mac, size_t macSize);
  SymmetricCipher & AccessSymmetricCipher() {return m_ctr;}

  virtual BlockCipher & AccessBlockCipher() =0;
  virtual int DefaultDigestSize() const =0;

  const BlockCipher & GetBlockCipher() const {return const_cast<CCM_Base *>(this)->AccessBlockCipher();}
  byte *CBC_Buffer() {return m_buffer+REQUIRED_BLOCKSIZE;}

  enum {REQUIRED_BLOCKSIZE = 16};
  int m_digestSize, m_L;
  word64 m_messageLength, m_aadLength;
  CTR_Mode_ExternalCipher::Encryption m_ctr;
};

/// \brief CCM block cipher final implementation
/// \tparam T_BlockCipher block cipher
/// \tparam T_DefaultDigestSize default digest size, in bytes
/// \tparam T_IsEncryption direction in which to operate the cipher
/// \since Crypto++ 5.6.0
template <class T_BlockCipher, int T_DefaultDigestSize, bool T_IsEncryption>
class CCM_Final : public CCM_Base
{
public:
  static std::string StaticAlgorithmName()
    {return T_BlockCipher::StaticAlgorithmName() + std::string("/CCM");}
  bool IsForwardTransformation() const
    {return T_IsEncryption;}

private:
  BlockCipher & AccessBlockCipher() {return m_cipher;}
  int DefaultDigestSize() const {return T_DefaultDigestSize;}
  typename T_BlockCipher::Encryption m_cipher;
};

/// \brief CCM block cipher mode of operation
/// \tparam T_BlockCipher block cipher
/// \tparam T_DefaultDigestSize default digest size, in bytes
/// \details \p CCM provides the \p Encryption and \p Decryption typedef. See GCM_Base
///   and GCM_Final for the AuthenticatedSymmetricCipher implementation.
/// \sa <a href="http://www.cryptopp.com/wiki/CCM_Mode">CCM Mode</a> and
///   <A HREF="http://www.cryptopp.com/wiki/Modes_of_Operation">Modes of Operation</A>
///   on the Crypto++ wiki.
/// \since Crypto++ 5.6.0
template <class T_BlockCipher, int T_DefaultDigestSize = 16>
struct CCM : public AuthenticatedSymmetricCipherDocumentation
{
  typedef CCM_Final<T_BlockCipher, T_DefaultDigestSize, true> Encryption;
  typedef CCM_Final<T_BlockCipher, T_DefaultDigestSize, false> Decryption;
};

NAMESPACE_END

#endif

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Created: 2024-11-21 07:03