rng.h

00001 // rng.h - misc RNG related classes, see also osrng.h, randpool.h
00002 
00003 #ifndef CRYPTOPP_RNG_H
00004 #define CRYPTOPP_RNG_H
00005 
00006 #include "cryptlib.h"
00007 #include "filters.h"
00008 
00009 NAMESPACE_BEGIN(CryptoPP)
00010 
00011 //! linear congruential generator
00012 /*! originally by William S. England, do not use for cryptographic purposes */
00013 class LC_RNG : public RandomNumberGenerator
00014 {
00015 public:
00016         LC_RNG(word32 init_seed)
00017                 : seed(init_seed) {}
00018 
00019         void GenerateBlock(byte *output, size_t size);
00020 
00021         word32 GetSeed() {return seed;}
00022 
00023 private:
00024         word32 seed;
00025 
00026         static const word32 m;
00027         static const word32 q;
00028         static const word16 a;
00029         static const word16 r;
00030 };
00031 
00032 //! RNG derived from ANSI X9.17 Appendix C
00033 
00034 class CRYPTOPP_DLL X917RNG : public RandomNumberGenerator, public NotCopyable
00035 {
00036 public:
00037         // cipher will be deleted by destructor, deterministicTimeVector = 0 means obtain time vector from system
00038         X917RNG(BlockTransformation *cipher, const byte *seed, const byte *deterministicTimeVector = 0);
00039 
00040         void GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size);
00041 
00042 private:
00043         member_ptr<BlockTransformation> cipher;
00044         unsigned int S;                 // blocksize of cipher
00045         SecByteBlock dtbuf;     // buffer for enciphered timestamp
00046         SecByteBlock randseed, m_lastBlock, m_deterministicTimeVector;
00047 };
00048 
00049 /** This class implements Maurer's Universal Statistical Test for Random Bit Generators
00050     it is intended for measuring the randomness of *PHYSICAL* RNGs.
00051     For more details see his paper in Journal of Cryptology, 1992. */
00052 
00053 class MaurerRandomnessTest : public Bufferless<Sink>
00054 {
00055 public:
00056         MaurerRandomnessTest();
00057 
00058         size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking);
00059 
00060         // BytesNeeded() returns how many more bytes of input is needed by the test
00061         // GetTestValue() should not be called before BytesNeeded()==0
00062         unsigned int BytesNeeded() const {return n >= (Q+K) ? 0 : Q+K-n;}
00063 
00064         // returns a number between 0.0 and 1.0, describing the quality of the
00065         // random numbers entered
00066         double GetTestValue() const;
00067 
00068 private:
00069         enum {L=8, V=256, Q=2000, K=2000};
00070         double sum;
00071         unsigned int n;
00072         unsigned int tab[V];
00073 };
00074 
00075 NAMESPACE_END
00076 
00077 #endif

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