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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
+*/
+
+#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 &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