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