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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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