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rng.h

#ifndef CRYPTOPP_RNG_H
#define CRYPTOPP_RNG_H

#include "cryptlib.h"
#include "filters.h"

NAMESPACE_BEGIN(CryptoPP)

class NullRNG : public RandomNumberGenerator
{
        byte GenerateByte() {assert(false); return 0x7d;}
};


class LC_RNG : public RandomNumberGenerator
{
public:
        LC_RNG(word32 init_seed)
                : seedBytes((byte *)&seed) {seed=init_seed;}

        byte GenerateByte();

        word32 GetSeed() {return seed;}

private:
        word32 seed;
        byte *const seedBytes;

        static const word32 m;
        static const word32 q;
        static const word16 a;
        static const word16 r;
};


class X917RNG : public RandomNumberGenerator
{
public:
        // cipher will be deleted by destructor
        X917RNG(BlockTransformation *cipher, const byte *seed);

        byte GenerateByte();

private:
        member_ptr<BlockTransformation> cipher;
        const int S;                    // blocksize of cipher
        SecByteBlock dtbuf;     // buffer for enciphered timestamp
        SecByteBlock randseed, randbuf;
        int randbuf_counter;    // # of unused bytes left in randbuf
};

class MaurerRandomnessTest : public Sink
{
public:
        MaurerRandomnessTest();

        void Put(byte inByte);
        void Put(const byte *inString, unsigned int length);

        // BytesNeeded() returns how many more bytes of input is needed by the test
        // GetTestValue() should not be called before BytesNeeded()==0
        unsigned int BytesNeeded() const {return n >= (Q+K) ? 0 : Q+K-n;}

        // returns a number between 0.0 and 1.0, describing the quality of the
        // random numbers entered
        double GetTestValue() const;

private:
        enum {L=8, V=256, Q=2000, K=2000};
        double sum;
        unsigned int n;
        unsigned int tab[V];
};

NAMESPACE_END

#endif

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