/usr/include/crypto++/gf256.h is in libcrypto++-dev 5.6.1-9.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 | #ifndef CRYPTOPP_GF256_H
#define CRYPTOPP_GF256_H
#include "cryptlib.h"
NAMESPACE_BEGIN(CryptoPP)
//! GF(256) with polynomial basis
class GF256
{
public:
typedef byte Element;
typedef int RandomizationParameter;
GF256(byte modulus) : m_modulus(modulus) {}
Element RandomElement(RandomNumberGenerator &rng, int ignored = 0) const
{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
{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
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