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73 lines
1.5 KiB
73 lines
1.5 KiB
4 years ago
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// gf256.h - originally written and placed in the public domain by Wei Dai
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/// \file gf256.h
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/// \brief Classes and functions for schemes over GF(256)
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#ifndef CRYPTOPP_GF256_H
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#define CRYPTOPP_GF256_H
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#include "cryptlib.h"
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#include "misc.h"
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NAMESPACE_BEGIN(CryptoPP)
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/// \brief GF(256) with polynomial basis
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class GF256
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{
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public:
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typedef byte Element;
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typedef int RandomizationParameter;
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GF256(byte modulus) : m_modulus(modulus) {}
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Element RandomElement(RandomNumberGenerator &rng, int ignored = 0) const
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{CRYPTOPP_UNUSED(ignored); return rng.GenerateByte();}
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bool Equal(Element a, Element b) const
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{return a==b;}
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Element Zero() const
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{return 0;}
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Element Add(Element a, Element b) const
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{return a^b;}
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Element& Accumulate(Element &a, Element b) const
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{return a^=b;}
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Element Inverse(Element a) const
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{return a;}
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Element Subtract(Element a, Element b) const
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{return a^b;}
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Element& Reduce(Element &a, Element b) const
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{return a^=b;}
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Element Double(Element a) const
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{CRYPTOPP_UNUSED(a); return 0;}
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Element One() const
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{return 1;}
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Element Multiply(Element a, Element b) const;
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Element Square(Element a) const
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{return Multiply(a, a);}
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bool IsUnit(Element a) const
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{return a != 0;}
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Element MultiplicativeInverse(Element a) const;
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Element Divide(Element a, Element b) const
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{return Multiply(a, MultiplicativeInverse(b));}
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private:
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word m_modulus;
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};
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NAMESPACE_END
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#endif
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