// mdc.h - written and placed in the public domain by Wei Dai #ifndef CRYPTOPP_MDC_H #define CRYPTOPP_MDC_H /** \file */ #include "seckey.h" #include "misc.h" NAMESPACE_BEGIN(CryptoPP) //! _ template <class T> struct MDC_Info : public FixedBlockSize<T::DIGESTSIZE>, public FixedKeyLength<T::BLOCKSIZE> { static std::string StaticAlgorithmName() {return std::string("MDC/")+T::StaticAlgorithmName();} }; //! <a href="http://www.weidai.com/scan-mirror/cs.html#MDC">MDC</a> /*! a construction by Peter Gutmann to turn an iterated hash function into a PRF */ template <class T> class MDC : public MDC_Info<T> { 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 ¶ms) { 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