gf256.h

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// gf256.h - originally written and placed in the public domain by Wei Dai
 
 
#ifndef CRYPTOPP_GF256_H
#define CRYPTOPP_GF256_H
 
#include "cryptlib.h"
#include "misc.h"
 
NAMESPACE_BEGIN(CryptoPP)
 
 
class GF256
{
public:
        typedef byte Element;
        typedef int RandomizationParameter;
 
        GF256(byte modulus) : m_modulus(modulus) {}
 
        Element RandomElement(RandomNumberGenerator &rng, int ignored = 0) const
                {CRYPTOPP_UNUSED(ignored); return rng.GenerateByte();}
 
        bool Equal(Element a, Element b) const
                {return a==b;}
 
        Element Zero() const
                {return 0;}
 
        Element Add(Element a, Element b) const
                {return a^b;}
 
        Element& Accumulate(Element &a, Element b) const
                {return a^=b;}
 
        Element Inverse(Element a) const
                {return a;}
 
        Element Subtract(Element a, Element b) const
                {return a^b;}
 
        Element& Reduce(Element &a, Element b) const
                {return a^=b;}
 
        Element Double(Element a) const
                {CRYPTOPP_UNUSED(a); return 0;}
 
        Element One() const
                {return 1;}
 
        Element Multiply(Element a, Element b) const;
 
        Element Square(Element a) const
                {return Multiply(a, a);}
 
        bool IsUnit(Element a) const
                {return a != 0;}
 
        Element MultiplicativeInverse(Element a) const;
 
        Element Divide(Element a, Element b) const
                {return Multiply(a, MultiplicativeInverse(b));}
 
private:
        word m_modulus;
};
 
NAMESPACE_END
 
#endif