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# blumshub.h

    00001 #ifndef CRYPTOPP_BLUMSHUB_H
    00002 #define CRYPTOPP_BLUMSHUB_H
    00003
    00004 #include "modarith.h"
    00005
    00006 NAMESPACE_BEGIN(CryptoPP)
    00007
    00008 class BlumGoldwasserPublicKey;
    00009 class BlumGoldwasserPrivateKey;
    00010
    00011 //! BlumBlumShub without factorization of the modulus
    00012 class PublicBlumBlumShub : public RandomNumberGenerator,
    00013                                                    public StreamTransformation
    00014 {
    00015 public:
    00016         PublicBlumBlumShub(const Integer &n, const Integer &seed);
    00017
    00018         unsigned int GenerateBit();
    00019         byte GenerateByte();
    00020
    00021         void ProcessData(byte *outString, const byte *inString, size_t length)
    00022         {
    00023                 while (length--)
    00024                         *outString++ = *inString ^ GenerateByte();
    00025         }
    00026
    00027         bool IsSelfInverting() const {return true;}
    00028         bool IsForwardTransformation() const {return true;}
    00029
    00030 protected:
    00031         ModularArithmetic modn;
    00032         word maxBits, bitsLeft;
    00033         Integer current;
    00034
    00035         friend class BlumGoldwasserPublicKey;
    00036         friend class BlumGoldwasserPrivateKey;
    00037 };
    00038
    00039 //! BlumBlumShub with factorization of the modulus
    00040 class BlumBlumShub : public PublicBlumBlumShub
    00041 {
    00042 public:
    00043         // Make sure p and q are both primes congruent to 3 mod 4 and at least 512 bits long,
    00044         // seed is the secret key and should be about as big as p*q
    00045         BlumBlumShub(const Integer &p, const Integer &q, const Integer &seed);
    00046
    00047         bool IsRandomAccess() const {return true;}
    00048         void Seek(lword index);
    00049
    00050 protected:
    00051         const Integer p, q;
    00052         const Integer x0;
    00053 };
    00054
    00055 NAMESPACE_END
    00056
    00057 #endif