112 lines
4.2 KiB
C++
112 lines
4.2 KiB
C++
// rng.h - originally written and placed in the public domain by Wei Dai
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/// \file rng.h
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/// \brief Miscellaneous classes for RNGs
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/// \details This file contains miscellaneous classes for RNGs, including LC_RNG(),
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/// X917RNG() and MaurerRandomnessTest()
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/// \sa osrng.h, randpool.h
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#ifndef CRYPTOPP_RNG_H
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#define CRYPTOPP_RNG_H
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#include "cryptlib.h"
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#include "filters.h"
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#include "smartptr.h"
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NAMESPACE_BEGIN(CryptoPP)
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/// \brief Linear Congruential Generator (LCG)
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/// \details Originally propsed by William S. England.
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/// \warning LC_RNG is suitable for simulations, where uniformaly distrubuted numbers are
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/// required quickly. It should not be used for cryptographic purposes.
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class LC_RNG : public RandomNumberGenerator
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{
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public:
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/// \brief Construct a Linear Congruential Generator (LCG)
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/// \param init_seed the initial value for the generator
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LC_RNG(word32 init_seed)
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: seed(init_seed) {}
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void GenerateBlock(byte *output, size_t size);
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word32 GetSeed() {return seed;}
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private:
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word32 seed;
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static const word32 m;
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static const word32 q;
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static const word16 a;
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static const word16 r;
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};
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/// \brief ANSI X9.17 RNG
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/// \details X917RNG is from ANSI X9.17 Appendix C, and it uses a 64-bit block cipher, like TripleDES.
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/// If you use a 128-bit block cipher, like AES, then you are effectively using an ANSI X9.31 generator.
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/// \details You should reseed the generator after a fork() to avoid multiple generators
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/// with the same internal state.
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/// \sa AutoSeededX917RNG, DefaultAutoSeededRNG
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class CRYPTOPP_DLL X917RNG : public RandomNumberGenerator, public NotCopyable
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{
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public:
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/// \brief Construct a X917RNG
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/// \param cipher the block cipher to use for the generator
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/// \param seed a byte buffer to use as a seed
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/// \param deterministicTimeVector additional entropy
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/// \details <tt>cipher</tt> will be deleted by the destructor. <tt>seed</tt> must be at least
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/// BlockSize() in length. <tt>deterministicTimeVector = 0</tt> means obtain time vector
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/// from the system.
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/// \details When constructing a X917RNG, the generator must be keyed or an access
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/// violation will occur because the time vector is encrypted using the block cipher.
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/// To key the generator during constructions, perform the following:
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/// <pre>
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/// SecByteBlock key(AES::DEFAULT_KEYLENGTH), seed(AES::BLOCKSIZE);
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/// OS_GenerateRandomBlock(false, key, key.size());
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/// OS_GenerateRandomBlock(false, seed, seed.size());
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/// X917RNG prng(new AES::Encryption(key, AES::DEFAULT_KEYLENGTH), seed, NULLPTR);</pre>
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/// \sa AutoSeededX917RNG
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X917RNG(BlockTransformation *cipher, const byte *seed, const byte *deterministicTimeVector = NULLPTR);
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void GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size);
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private:
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member_ptr<BlockTransformation> m_cipher;
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const unsigned int m_size; // S, blocksize of cipher
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SecByteBlock m_datetime; // DT, buffer for enciphered timestamp
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SecByteBlock m_randseed, m_lastBlock, m_deterministicTimeVector;
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};
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/// \brief Maurer's Universal Statistical Test for Random Bit Generators
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/// \details This class implements Maurer's Universal Statistical Test for
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/// Random Bit Generators. It is intended for measuring the randomness of
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/// *PHYSICAL* RNGs.
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/// \details For more details see Maurer's paper in Journal of Cryptology, 1992.
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class MaurerRandomnessTest : public Bufferless<Sink>
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{
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public:
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/// \brief Construct a MaurerRandomnessTest
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MaurerRandomnessTest();
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size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking);
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/// \brief Provides the number of bytes of input is needed by the test
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/// \return how many more bytes of input is needed by the test
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// BytesNeeded() returns how many more bytes of input is needed by the test
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// GetTestValue() should not be called before BytesNeeded()==0
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unsigned int BytesNeeded() const {return n >= (Q+K) ? 0 : Q+K-n;}
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// returns a number between 0.0 and 1.0, describing the quality of the
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// random numbers entered
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double GetTestValue() const;
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private:
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enum {L=8, V=256, Q=2000, K=2000};
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double sum;
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unsigned int n;
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unsigned int tab[V];
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};
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NAMESPACE_END
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#endif
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