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rng.h

00001 #ifndef CRYPTOPP_RNG_H
00002 #define CRYPTOPP_RNG_H
00003 
00004 #include "cryptlib.h"
00005 #include "filters.h"
00006 
00007 NAMESPACE_BEGIN(CryptoPP)
00008 
00009 //! linear congruential generator
00010 /*! originally by William S. England, do not use for cryptographic purposes */
00011 class LC_RNG : public RandomNumberGenerator
00012 {
00013 public:
00014         LC_RNG(word32 init_seed)
00015                 : seed(init_seed) {}
00016 
00017         byte GenerateByte();
00018 
00019         word32 GetSeed() {return seed;}
00020 
00021 private:
00022         word32 seed;
00023 
00024         static const word32 m;
00025         static const word32 q;
00026         static const word16 a;
00027         static const word16 r;
00028 };
00029 
00030 //! RNG derived from ANSI X9.17 Appendix C
00031 
00032 class X917RNG : public RandomNumberGenerator
00033 {
00034 public:
00035         // cipher will be deleted by destructor, deterministicTimeVector = 0 means obtain time vector from system
00036         X917RNG(BlockTransformation *cipher, const byte *seed, unsigned long deterministicTimeVector = 0);
00037 
00038         byte GenerateByte();
00039 
00040 private:
00041         member_ptr<BlockTransformation> cipher;
00042         const int S;                    // blocksize of cipher
00043         SecByteBlock dtbuf;     // buffer for enciphered timestamp
00044         SecByteBlock randseed, randbuf;
00045         int randbuf_counter;    // # of unused bytes left in randbuf
00046         unsigned long 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 Sink
00054 {
00055 public:
00056         MaurerRandomnessTest();
00057 
00058         void Put(byte inByte);
00059         void Put(const byte *inString, unsigned int length);
00060 
00061         // BytesNeeded() returns how many more bytes of input is needed by the test
00062         // GetTestValue() should not be called before BytesNeeded()==0
00063         unsigned int BytesNeeded() const {return n >= (Q+K) ? 0 : Q+K-n;}
00064 
00065         // returns a number between 0.0 and 1.0, describing the quality of the
00066         // random numbers entered
00067         double GetTestValue() const;
00068 
00069 private:
00070         enum {L=8, V=256, Q=2000, K=2000};
00071         double sum;
00072         unsigned int n;
00073         unsigned int tab[V];
00074 };
00075 
00076 NAMESPACE_END
00077 
00078 #endif

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