gf2_32.h

Go to the documentation of this file.

// gf2_32.h - originally written and placed in the public domain by Wei Dai
 
/// \file gf2_32.h
/// \brief Classes and functions for schemes over GF(2^32)
 
#ifndef CRYPTOPP_GF2_32_H
#define CRYPTOPP_GF2_32_H
 
#include "cryptlib.h"
#include "secblock.h"
#include "misc.h"
 
NAMESPACE_BEGIN(CryptoPP)
 
/// \brief GF(2^32) with polynomial basis
class GF2_32
{
public:
    typedef word32 Element;
    typedef int RandomizationParameter;
 
    GF2_32(word32 modulus=0x0000008D) : m_modulus(modulus) {}
 
    Element RandomElement(RandomNumberGenerator &rng, int ignored = 0) const
        {CRYPTOPP_UNUSED(ignored); return rng.GenerateWord32();}
 
    bool Equal(Element a, Element b) const
        {return a==b;}
 
    Element Identity() 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 MultiplicativeIdentity() 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:
    word32 m_modulus;
};
 
NAMESPACE_END
 
#endif