mdc.h
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// mdc.h - written and placed in the public domain by Wei Dai
#ifndef CRYPTOPP_MDC_H
#define CRYPTOPP_MDC_H
//! \file mdc.h
//! \brief Classes for the MDC message digest
#include "seckey.h"
#include "secblock.h"
#include "misc.h"
NAMESPACE_BEGIN(CryptoPP)
//! \class MDC_Info
//! \brief MDC_Info cipher information
template <class T>
struct MDC_Info : public FixedBlockSize<T::DIGESTSIZE>, public FixedKeyLength<T::BLOCKSIZE>
{
static std::string StaticAlgorithmName() {return std::string("MDC/")+T::StaticAlgorithmName();}
};
//! \class MDC
//! \brief MDC cipher
//! \details MDC() is a construction by Peter Gutmann to turn an iterated hash function into a PRF
//! \sa <a href="http://www.weidai.com/scan-mirror/cs.html#MDC">MDC</a>
template <class T>
class MDC : public MDC_Info<T>
{
//! \class Enc
//! \brief MDC cipher encryption operation
class CRYPTOPP_NO_VTABLE Enc : public BlockCipherImpl<MDC_Info<T> >
{
typedef typename T::HashWordType HashWordType;
public:
void UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs &params)
{
this->AssertValidKeyLength(length);
memcpy_s(m_key, m_key.size(), userKey, this->KEYLENGTH);
T::CorrectEndianess(Key(), Key(), this->KEYLENGTH);
}
void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
T::CorrectEndianess(Buffer(), (HashWordType *)inBlock, this->BLOCKSIZE);
T::Transform(Buffer(), Key());
if (xorBlock)
{
T::CorrectEndianess(Buffer(), Buffer(), this->BLOCKSIZE);
xorbuf(outBlock, xorBlock, m_buffer, this->BLOCKSIZE);
}
else
T::CorrectEndianess((HashWordType *)outBlock, Buffer(), this->BLOCKSIZE);
}
bool IsPermutation() const {return false;}
unsigned int OptimalDataAlignment() const {return sizeof(HashWordType);}
private:
HashWordType *Key() {return (HashWordType *)m_key.data();}
const HashWordType *Key() const {return (const HashWordType *)m_key.data();}
HashWordType *Buffer() const {return (HashWordType *)m_buffer.data();}
// VC60 workaround: bug triggered if using FixedSizeAllocatorWithCleanup
FixedSizeSecBlock<byte, MDC_Info<T>::KEYLENGTH, AllocatorWithCleanup<byte> > m_key;
mutable FixedSizeSecBlock<byte, MDC_Info<T>::BLOCKSIZE, AllocatorWithCleanup<byte> > m_buffer;
};
public:
//! use BlockCipher interface
typedef BlockCipherFinal<ENCRYPTION, Enc> Encryption;
};
NAMESPACE_END
#endif
MDC_Info
MDC_Info cipher information.
Definition: mdc.h:18
FixedKeyLength
Inherited by keyed algorithms with fixed key length.
Definition: seckey.h:128
misc.h
Utility functions for the Crypto++ library.
FixedKeyLength< T::BLOCKSIZE >::KEYLENGTH
static const int KEYLENGTH
The default key length used by the algorithm provided as a constant.
Definition: seckey.h:133
MDC
MDC cipher.
Definition: mdc.h:29
memcpy_s
void memcpy_s(void *dest, size_t sizeInBytes, const void *src, size_t count)
Bounds checking replacement for memcpy()
Definition: misc.h:356
AllocatorWithCleanup< byte >
secblock.h
Classes and functions for secure memory allocations.
MDC::Encryption
BlockCipherFinal< ENCRYPTION, Enc > Encryption
use BlockCipher interface
Definition: mdc.h:74
FixedBlockSize
Inherited by algorithms with fixed block size.
Definition: seckey.h:34
seckey.h
Classes and functions for implementing secret key algorithms.
BlockCipherFinal< ENCRYPTION, Enc >
FixedSizeSecBlock
Fixed size stack-based SecBlock.
Definition: secblock.h:753
xorbuf
void xorbuf(byte *buf, const byte *mask, size_t count)
Performs an XOR of a buffer with a mask.
Definition: misc.cpp:28
BlockCipherImpl
Provides a base implementation of Algorithm and SimpleKeyingInterface for block ciphers.
Definition: seckey.h:326
CryptoPP
Crypto++ library namespace.
FixedBlockSize< T::DIGESTSIZE >::BLOCKSIZE
static const int BLOCKSIZE
The block size of the algorithm provided as a constant.
Definition: seckey.h:38
Name::Key
const char * Key()
ConstByteArrayParameter.
Definition: argnames.h:20
NameValuePairs
Interface for retrieving values given their names.
Definition: cryptlib.h:277