include/cryptopp/gf2_32.h

0001 // gf2_32.h - originally written and placed in the public domain by Wei Dai

0002
0003 /// \file gf2_32.h

0004 /// \brief Classes and functions for schemes over GF(2^32)

0005
0006 #ifndef CRYPTOPP_GF2_32_H
0007 #define CRYPTOPP_GF2_32_H
0008
0009 #include "cryptlib.h"
0010 #include "secblock.h"
0011 #include "misc.h"
0012
0013 NAMESPACE_BEGIN(CryptoPP)
0014
0015 /// \brief GF(2^32) with polynomial basis

0016 class GF2_32
0017 {
0018 public:
0019     typedef word32 Element;
0020     typedef int RandomizationParameter;
0021
0022     GF2_32(word32 modulus=0x0000008D) : m_modulus(modulus) {}
0023
0024     Element RandomElement(RandomNumberGenerator &rng, int ignored = 0) const
0025         {CRYPTOPP_UNUSED(ignored); return rng.GenerateWord32();}
0026
0027     bool Equal(Element a, Element b) const
0028         {return a==b;}
0029
0030     Element Identity() const
0031         {return 0;}
0032
0033     Element Add(Element a, Element b) const
0034         {return a^b;}
0035
0036     Element& Accumulate(Element &a, Element b) const
0037         {return a^=b;}
0038
0039     Element Inverse(Element a) const
0040         {return a;}
0041
0042     Element Subtract(Element a, Element b) const
0043         {return a^b;}
0044
0045     Element& Reduce(Element &a, Element b) const
0046         {return a^=b;}
0047
0048     Element Double(Element a) const
0049         {CRYPTOPP_UNUSED(a); return 0;}
0050
0051     Element MultiplicativeIdentity() const
0052         {return 1;}
0053
0054     Element Multiply(Element a, Element b) const;
0055
0056     Element Square(Element a) const
0057         {return Multiply(a, a);}
0058
0059     bool IsUnit(Element a) const
0060         {return a != 0;}
0061
0062     Element MultiplicativeInverse(Element a) const;
0063
0064     Element Divide(Element a, Element b) const
0065         {return Multiply(a, MultiplicativeInverse(b));}
0066
0067 private:
0068     word32 m_modulus;
0069 };
0070
0071 NAMESPACE_END
0072
0073 #endif