64 lines
2.0 KiB
C++
64 lines
2.0 KiB
C++
// trunhash.h - originally written and placed in the public domain by Wei Dai
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/// \file trunhash.h
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/// \brief Classes for truncated hashes
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#ifndef CRYPTOPP_TRUNHASH_H
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#define CRYPTOPP_TRUNHASH_H
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#include "cryptlib.h"
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NAMESPACE_BEGIN(CryptoPP)
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/// \brief Null hash
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/// \details A null hash that conforms to HashTransformation interface
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class NullHash : public HashTransformation
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{
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public:
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void Update(const byte *input, size_t length)
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{CRYPTOPP_UNUSED(input);CRYPTOPP_UNUSED(length);}
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unsigned int DigestSize() const
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{return 0;}
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void TruncatedFinal(byte *digest, size_t digestSize)
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{CRYPTOPP_UNUSED(digest);CRYPTOPP_UNUSED(digestSize);}
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bool TruncatedVerify(const byte *digest, size_t digestLength)
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{CRYPTOPP_UNUSED(digest);CRYPTOPP_UNUSED(digestLength);return true;}
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};
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/// \brief Construct new HashModule with smaller digest size from an existing one
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/// \tparam T HashTransformation derived class
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template <class T>
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class TruncatedHashTemplate : public HashTransformation
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{
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public:
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/// \brief Construct a TruncatedHashTemplate
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TruncatedHashTemplate(T hm, unsigned int digestSize)
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: m_hm(hm), m_digestSize(digestSize) {}
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/// \brief Construct a TruncatedHashTemplate
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TruncatedHashTemplate(const byte *key, size_t keyLength, unsigned int digestSize)
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: m_hm(key, keyLength), m_digestSize(digestSize) {}
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/// \brief Construct a TruncatedHashTemplate
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TruncatedHashTemplate(size_t digestSize)
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: m_digestSize(digestSize) {}
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void Restart()
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{m_hm.Restart();}
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void Update(const byte *input, size_t length)
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{m_hm.Update(input, length);}
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unsigned int DigestSize() const {return m_digestSize;}
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void TruncatedFinal(byte *digest, size_t digestSize)
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{m_hm.TruncatedFinal(digest, digestSize);}
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bool TruncatedVerify(const byte *digest, size_t digestLength)
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{return m_hm.TruncatedVerify(digest, digestLength);}
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private:
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T m_hm;
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unsigned int m_digestSize;
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};
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typedef TruncatedHashTemplate<HashTransformation &> TruncatedHashModule;
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NAMESPACE_END
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#endif
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