mdc.h
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// mdc.h - originally written and placed in the public domain by Wei Dai
/// \file mdc.h
/// \brief Classes for the MDC message digest
#ifndef CRYPTOPP_MDC_H
#define CRYPTOPP_MDC_H
#include "seckey.h"
#include "secblock.h"
#include "misc.h"
// GCC cast warning
#define HashWordPtr(x) ((HashWordType*)(void*)(x))
#define ConstHashWordPtr(x) ((const HashWordType*)(const void*)(x))
NAMESPACE_BEGIN(CryptoPP)
/// \tparam B BlockCipher derived class
/// \brief MDC_Info cipher information
template <class B>
struct MDC_Info : public FixedBlockSize<B::DIGESTSIZE>, public FixedKeyLength<B::BLOCKSIZE>
{
static std::string StaticAlgorithmName() {return std::string("MDC/")+B::StaticAlgorithmName();}
};
/// \brief MDC cipher
/// \tparam H HashTransformation derived class
/// \details MDC() is a construction by Peter Gutmann to turn an iterated hash function into a PRF
/// \sa <a href="http://www.cryptopp.com/wiki/MDC">MDC</a>
template <class H>
class MDC : public MDC_Info<H>
{
/// \brief MDC cipher encryption operation
class CRYPTOPP_NO_VTABLE Enc : public BlockCipherImpl<MDC_Info<H> >
{
typedef typename H::HashWordType HashWordType;
public:
void UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs &params)
{
CRYPTOPP_UNUSED(params);
this->AssertValidKeyLength(length);
ConditionalByteReverse(BIG_ENDIAN_ORDER, Key(), ConstHashWordPtr(userKey), this->KEYLENGTH);
}
void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
ConditionalByteReverse(BIG_ENDIAN_ORDER, Buffer(), ConstHashWordPtr(inBlock), this->BLOCKSIZE);
H::Transform(Buffer(), Key());
if (xorBlock)
{
ConditionalByteReverse(BIG_ENDIAN_ORDER, Buffer(), Buffer(), this->BLOCKSIZE);
xorbuf(outBlock, xorBlock, m_buffer, this->BLOCKSIZE);
}
else
{
ConditionalByteReverse(BIG_ENDIAN_ORDER, HashWordPtr(outBlock), Buffer(), this->BLOCKSIZE);
}
}
bool IsPermutation() const {return false;}
unsigned int OptimalDataAlignment() const {return sizeof(HashWordType);}
private:
HashWordType *Key() {return HashWordPtr(m_key.data());}
const HashWordType *Key() const {return ConstHashWordPtr(m_key.data());}
HashWordType *Buffer() const {return HashWordPtr(m_buffer.data());}
// VC60 workaround: bug triggered if using FixedSizeAllocatorWithCleanup
FixedSizeSecBlock<byte, MDC_Info<H>::KEYLENGTH, AllocatorWithCleanup<byte> > m_key;
mutable FixedSizeSecBlock<byte, MDC_Info<H>::BLOCKSIZE, AllocatorWithCleanup<byte> > m_buffer;
};
public:
// use BlockCipher interface
typedef BlockCipherFinal<ENCRYPTION, Enc> Encryption;
};
NAMESPACE_END
#endif
AllocatorWithCleanup
Allocates a block of memory with cleanup.
Definition secblock.h:188
BlockCipherFinal
Provides class member functions to key a block cipher.
Definition seckey.h:318
BlockCipherImpl
Provides a base implementation of Algorithm and SimpleKeyingInterface for block ciphers.
Definition seckey.h:306
FixedBlockSize
Inherited by algorithms with fixed block size.
Definition seckey.h:41
FixedKeyLength
Inherited by keyed algorithms with fixed key length.
Definition seckey.h:125
FixedSizeSecBlock
Fixed size stack-based SecBlock.
Definition secblock.h:1246
MDC
MDC cipher.
Definition mdc.h:33
NameValuePairs
Interface for retrieving values given their names.
Definition cryptlib.h:327
BIG_ENDIAN_ORDER
@ BIG_ENDIAN_ORDER
byte order is big-endian
Definition cryptlib.h:152
misc.h
Utility functions for the Crypto++ library.
ConditionalByteReverse
T ConditionalByteReverse(ByteOrder order, T value)
Reverses bytes in a value depending upon endianness.
Definition misc.h:2417
xorbuf
CRYPTOPP_DLL void xorbuf(byte *buf, const byte *mask, size_t count)
Performs an XOR of a buffer with a mask.
CryptoPP
Crypto++ library namespace.
secblock.h
Classes and functions for secure memory allocations.
seckey.h
Classes and functions for implementing secret key algorithms.
MDC_Info
MDC_Info cipher information.
Definition mdc.h:23