73 lines
2.1 KiB
C
73 lines
2.1 KiB
C
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// mdc.h - written and placed in the public domain by Wei Dai
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#ifndef CRYPTOPP_MDC_H
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#define CRYPTOPP_MDC_H
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/** \file
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*/
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#include "seckey.h"
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#include "misc.h"
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NAMESPACE_BEGIN(CryptoPP)
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//! _
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template <class T>
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struct MDC_Info : public FixedBlockSize<T::DIGESTSIZE>, public FixedKeyLength<T::BLOCKSIZE>
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{
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static std::string StaticAlgorithmName() {return std::string("MDC/")+T::StaticAlgorithmName();}
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};
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//! <a href="http://www.weidai.com/scan-mirror/cs.html#MDC">MDC</a>
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/*! a construction by Peter Gutmann to turn an iterated hash function into a PRF */
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template <class T>
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class MDC : public MDC_Info<T>
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{
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class CRYPTOPP_NO_VTABLE Enc : public BlockCipherImpl<MDC_Info<T> >
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{
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typedef typename T::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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this->AssertValidKeyLength(length);
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memcpy_s(m_key, m_key.size(), userKey, this->KEYLENGTH);
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T::CorrectEndianess(Key(), Key(), 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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T::CorrectEndianess(Buffer(), (HashWordType *)inBlock, this->BLOCKSIZE);
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T::Transform(Buffer(), Key());
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if (xorBlock)
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{
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T::CorrectEndianess(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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T::CorrectEndianess((HashWordType *)outBlock, Buffer(), this->BLOCKSIZE);
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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 (HashWordType *)m_key.data();}
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const HashWordType *Key() const {return (const HashWordType *)m_key.data();}
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HashWordType *Buffer() const {return (HashWordType *)m_buffer.data();}
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// VC60 workaround: bug triggered if using FixedSizeAllocatorWithCleanup
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FixedSizeSecBlock<byte, MDC_Info<T>::KEYLENGTH, AllocatorWithCleanup<byte> > m_key;
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mutable FixedSizeSecBlock<byte, MDC_Info<T>::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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