ext-cryptopp/blumshub.h
2020-04-09 11:52:05 -04:00

71 lines
2.0 KiB
C++

// blumshub.h - originally written and placed in the public domain by Wei Dai
/// \file blumshub.h
/// \brief Classes for Blum Blum Shub generator
#ifndef CRYPTOPP_BLUMSHUB_H
#define CRYPTOPP_BLUMSHUB_H
#include "cryptlib.h"
#include "modarith.h"
#include "integer.h"
NAMESPACE_BEGIN(CryptoPP)
/// \brief BlumBlumShub without factorization of the modulus
/// \details You should reseed the generator after a fork() to avoid multiple generators
/// with the same internal state.
class PublicBlumBlumShub : public RandomNumberGenerator,
public StreamTransformation
{
public:
virtual ~PublicBlumBlumShub() {}
/// \brief Construct a PublicBlumBlumShub
/// \param n the modulus
/// \param seed the seed for the generator
/// \details seed is the secret key and should be about as large as n.
PublicBlumBlumShub(const Integer &n, const Integer &seed);
unsigned int GenerateBit();
byte GenerateByte();
void GenerateBlock(byte *output, size_t size);
void ProcessData(byte *outString, const byte *inString, size_t length);
bool IsSelfInverting() const {return true;}
bool IsForwardTransformation() const {return true;}
protected:
ModularArithmetic modn;
Integer current;
word maxBits, bitsLeft;
};
/// \brief BlumBlumShub with factorization of the modulus
/// \details You should reseed the generator after a fork() to avoid multiple generators
/// with the same internal state.
class BlumBlumShub : public PublicBlumBlumShub
{
public:
virtual ~BlumBlumShub() {}
/// \brief Construct a BlumBlumShub
/// \param p the first prime factor
/// \param q the second prime factor
/// \param seed the seed for the generator
/// \details Esure p and q are both primes congruent to 3 mod 4 and at least 512 bits long.
/// seed is the secret key and should be about as large as p*q.
BlumBlumShub(const Integer &p, const Integer &q, const Integer &seed);
bool IsRandomAccess() const {return true;}
void Seek(lword index);
protected:
const Integer p, q;
const Integer x0;
};
NAMESPACE_END
#endif