/usr/include/crypto++/modarith.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 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 | #ifndef CRYPTOPP_MODARITH_H
#define CRYPTOPP_MODARITH_H
// implementations are in integer.cpp
#include "cryptlib.h"
#include "misc.h"
#include "integer.h"
#include "algebra.h"
NAMESPACE_BEGIN(CryptoPP)
CRYPTOPP_DLL_TEMPLATE_CLASS AbstractGroup<Integer>;
CRYPTOPP_DLL_TEMPLATE_CLASS AbstractRing<Integer>;
CRYPTOPP_DLL_TEMPLATE_CLASS AbstractEuclideanDomain<Integer>;
//! ring of congruence classes modulo n
/*! \note this implementation represents each congruence class as the smallest non-negative integer in that class */
class CRYPTOPP_DLL ModularArithmetic : public AbstractRing<Integer>
{
public:
typedef int RandomizationParameter;
typedef Integer Element;
ModularArithmetic(const Integer &modulus = Integer::One())
: m_modulus(modulus), m_result((word)0, modulus.reg.size()) {}
ModularArithmetic(const ModularArithmetic &ma)
: m_modulus(ma.m_modulus), m_result((word)0, m_modulus.reg.size()) {}
ModularArithmetic(BufferedTransformation &bt); // construct from BER encoded parameters
virtual ModularArithmetic * Clone() const {return new ModularArithmetic(*this);}
void DEREncode(BufferedTransformation &bt) const;
void DEREncodeElement(BufferedTransformation &out, const Element &a) const;
void BERDecodeElement(BufferedTransformation &in, Element &a) const;
const Integer& GetModulus() const {return m_modulus;}
void SetModulus(const Integer &newModulus) {m_modulus = newModulus; m_result.reg.resize(m_modulus.reg.size());}
virtual bool IsMontgomeryRepresentation() const {return false;}
virtual Integer ConvertIn(const Integer &a) const
{return a%m_modulus;}
virtual Integer ConvertOut(const Integer &a) const
{return a;}
const Integer& Half(const Integer &a) const;
bool Equal(const Integer &a, const Integer &b) const
{return a==b;}
const Integer& Identity() const
{return Integer::Zero();}
const Integer& Add(const Integer &a, const Integer &b) const;
Integer& Accumulate(Integer &a, const Integer &b) const;
const Integer& Inverse(const Integer &a) const;
const Integer& Subtract(const Integer &a, const Integer &b) const;
Integer& Reduce(Integer &a, const Integer &b) const;
const Integer& Double(const Integer &a) const
{return Add(a, a);}
const Integer& MultiplicativeIdentity() const
{return Integer::One();}
const Integer& Multiply(const Integer &a, const Integer &b) const
{return m_result1 = a*b%m_modulus;}
const Integer& Square(const Integer &a) const
{return m_result1 = a.Squared()%m_modulus;}
bool IsUnit(const Integer &a) const
{return Integer::Gcd(a, m_modulus).IsUnit();}
const Integer& MultiplicativeInverse(const Integer &a) const
{return m_result1 = a.InverseMod(m_modulus);}
const Integer& Divide(const Integer &a, const Integer &b) const
{return Multiply(a, MultiplicativeInverse(b));}
Integer CascadeExponentiate(const Integer &x, const Integer &e1, const Integer &y, const Integer &e2) const;
void SimultaneousExponentiate(Element *results, const Element &base, const Integer *exponents, unsigned int exponentsCount) const;
unsigned int MaxElementBitLength() const
{return (m_modulus-1).BitCount();}
unsigned int MaxElementByteLength() const
{return (m_modulus-1).ByteCount();}
Element RandomElement( RandomNumberGenerator &rng , const RandomizationParameter &ignore_for_now = 0 ) const
// left RandomizationParameter arg as ref in case RandomizationParameter becomes a more complicated struct
{
return Element( rng , Integer( (long) 0) , m_modulus - Integer( (long) 1 ) ) ;
}
bool operator==(const ModularArithmetic &rhs) const
{return m_modulus == rhs.m_modulus;}
static const RandomizationParameter DefaultRandomizationParameter ;
protected:
Integer m_modulus;
mutable Integer m_result, m_result1;
};
// const ModularArithmetic::RandomizationParameter ModularArithmetic::DefaultRandomizationParameter = 0 ;
//! do modular arithmetics in Montgomery representation for increased speed
/*! \note the Montgomery representation represents each congruence class [a] as a*r%n, where r is a convenient power of 2 */
class CRYPTOPP_DLL MontgomeryRepresentation : public ModularArithmetic
{
public:
MontgomeryRepresentation(const Integer &modulus); // modulus must be odd
virtual ModularArithmetic * Clone() const {return new MontgomeryRepresentation(*this);}
bool IsMontgomeryRepresentation() const {return true;}
Integer ConvertIn(const Integer &a) const
{return (a<<(WORD_BITS*m_modulus.reg.size()))%m_modulus;}
Integer ConvertOut(const Integer &a) const;
const Integer& MultiplicativeIdentity() const
{return m_result1 = Integer::Power2(WORD_BITS*m_modulus.reg.size())%m_modulus;}
const Integer& Multiply(const Integer &a, const Integer &b) const;
const Integer& Square(const Integer &a) const;
const Integer& MultiplicativeInverse(const Integer &a) const;
Integer CascadeExponentiate(const Integer &x, const Integer &e1, const Integer &y, const Integer &e2) const
{return AbstractRing<Integer>::CascadeExponentiate(x, e1, y, e2);}
void SimultaneousExponentiate(Element *results, const Element &base, const Integer *exponents, unsigned int exponentsCount) const
{AbstractRing<Integer>::SimultaneousExponentiate(results, base, exponents, exponentsCount);}
private:
Integer m_u;
mutable IntegerSecBlock m_workspace;
};
NAMESPACE_END
#endif
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