85 lines
2.7 KiB
C++
85 lines
2.7 KiB
C++
// mdc.h - originally written and placed in the public domain by Wei Dai
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/// \file mdc.h
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/// \brief Classes for the MDC message digest
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#ifndef CRYPTOPP_MDC_H
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#define CRYPTOPP_MDC_H
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#include "seckey.h"
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#include "secblock.h"
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#include "misc.h"
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// GCC cast warning
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#define HashWordPtr(x) ((HashWordType*)(void*)(x))
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#define ConstHashWordPtr(x) ((const HashWordType*)(const void*)(x))
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NAMESPACE_BEGIN(CryptoPP)
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/// \tparam B BlockCipher derived class
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/// \brief MDC_Info cipher information
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template <class B>
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struct MDC_Info : public FixedBlockSize<B::DIGESTSIZE>, public FixedKeyLength<B::BLOCKSIZE>
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{
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static std::string StaticAlgorithmName() {return std::string("MDC/")+B::StaticAlgorithmName();}
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};
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/// \brief MDC cipher
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/// \tparam H HashTransformation derived class
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/// \details MDC() is a construction by Peter Gutmann to turn an iterated hash function into a PRF
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/// \sa <a href="http://www.cryptopp.com/wiki/MDC">MDC</a>
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template <class H>
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class MDC : public MDC_Info<H>
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{
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/// \brief MDC cipher encryption operation
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class CRYPTOPP_NO_VTABLE Enc : public BlockCipherImpl<MDC_Info<H> >
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{
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typedef typename H::HashWordType HashWordType;
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public:
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void UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs ¶ms)
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{
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CRYPTOPP_UNUSED(params);
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this->AssertValidKeyLength(length);
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ConditionalByteReverse(BIG_ENDIAN_ORDER, Key(), ConstHashWordPtr(userKey), this->KEYLENGTH);
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}
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void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
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{
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ConditionalByteReverse(BIG_ENDIAN_ORDER, Buffer(), ConstHashWordPtr(inBlock), this->BLOCKSIZE);
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H::Transform(Buffer(), Key());
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if (xorBlock)
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{
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ConditionalByteReverse(BIG_ENDIAN_ORDER, Buffer(), Buffer(), this->BLOCKSIZE);
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xorbuf(outBlock, xorBlock, m_buffer, this->BLOCKSIZE);
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}
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else
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{
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ConditionalByteReverse(BIG_ENDIAN_ORDER, HashWordPtr(outBlock), Buffer(), this->BLOCKSIZE);
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}
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}
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bool IsPermutation() const {return false;}
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unsigned int OptimalDataAlignment() const {return sizeof(HashWordType);}
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private:
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HashWordType *Key() {return HashWordPtr(m_key.data());}
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const HashWordType *Key() const {return ConstHashWordPtr(m_key.data());}
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HashWordType *Buffer() const {return HashWordPtr(m_buffer.data());}
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// VC60 workaround: bug triggered if using FixedSizeAllocatorWithCleanup
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FixedSizeSecBlock<byte, MDC_Info<H>::KEYLENGTH, AllocatorWithCleanup<byte> > m_key;
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mutable FixedSizeSecBlock<byte, MDC_Info<H>::BLOCKSIZE, AllocatorWithCleanup<byte> > m_buffer;
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};
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public:
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// use BlockCipher interface
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typedef BlockCipherFinal<ENCRYPTION, Enc> Encryption;
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};
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NAMESPACE_END
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#endif
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