Crypto++ 8.9
Free C++ class library of cryptographic schemes
rng.h
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1// rng.h - originally written and placed in the public domain by Wei Dai
2
3/// \file rng.h
4/// \brief Miscellaneous classes for RNGs
5/// \details This file contains miscellaneous classes for RNGs, including LC_RNG(),
6/// X917RNG() and MaurerRandomnessTest()
7/// \sa osrng.h, randpool.h
8
9#ifndef CRYPTOPP_RNG_H
10#define CRYPTOPP_RNG_H
11
12#include "cryptlib.h"
13#include "filters.h"
14#include "smartptr.h"
15
16NAMESPACE_BEGIN(CryptoPP)
17
18/// \brief Linear Congruential Generator (LCG)
19/// \details Originally propsed by William S. England.
20/// \warning LC_RNG is suitable for simulations, where uniformaly distributed numbers are
21/// required quickly. It should not be used for cryptographic purposes.
23{
24public:
25 /// \brief Construct a Linear Congruential Generator (LCG)
26 /// \param init_seed the initial value for the generator
27 LC_RNG(word32 init_seed)
28 : seed(init_seed) {}
29
30 void GenerateBlock(byte *output, size_t size);
31
32 word32 GetSeed() {return seed;}
33
34private:
35 word32 seed;
36
37 static const word32 m;
38 static const word32 q;
39 static const word16 a;
40 static const word16 r;
41};
42
43/// \brief ANSI X9.17 RNG
44/// \details X917RNG is from ANSI X9.17 Appendix C, and it uses a 64-bit block cipher, like TripleDES.
45/// If you use a 128-bit block cipher, like AES, then you are effectively using an ANSI X9.31 generator.
46/// \details You should reseed the generator after a fork() to avoid multiple generators
47/// with the same internal state.
48/// \sa AutoSeededX917RNG, DefaultAutoSeededRNG
49class CRYPTOPP_DLL X917RNG : public RandomNumberGenerator, public NotCopyable
50{
51public:
52 /// \brief Construct a X917RNG
53 /// \param cipher the block cipher to use for the generator
54 /// \param seed a byte buffer to use as a seed
55 /// \param deterministicTimeVector additional entropy
56 /// \details <tt>cipher</tt> will be deleted by the destructor. <tt>seed</tt> must be at least
57 /// BlockSize() in length. <tt>deterministicTimeVector = 0</tt> means obtain time vector
58 /// from the system.
59 /// \details When constructing a X917RNG, the generator must be keyed or an access
60 /// violation will occur because the time vector is encrypted using the block cipher.
61 /// To key the generator during constructions, perform the following:
62 /// <pre>
63 /// SecByteBlock key(AES::DEFAULT_KEYLENGTH), seed(AES::BLOCKSIZE);
64 /// OS_GenerateRandomBlock(false, key, key.size());
65 /// OS_GenerateRandomBlock(false, seed, seed.size());
66 /// X917RNG prng(new AES::Encryption(key, AES::DEFAULT_KEYLENGTH), seed, NULLPTR);</pre>
67 /// \sa AutoSeededX917RNG
68 X917RNG(BlockTransformation *cipher, const byte *seed, const byte *deterministicTimeVector = NULLPTR);
69
70 void GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size);
71
72private:
74 const unsigned int m_size; // S, blocksize of cipher
75 SecByteBlock m_datetime; // DT, buffer for enciphered timestamp
76 SecByteBlock m_randseed, m_lastBlock, m_deterministicTimeVector;
77};
78
79/// \brief Maurer's Universal Statistical Test for Random Bit Generators
80/// \details This class implements Maurer's Universal Statistical Test for
81/// Random Bit Generators. It is intended for measuring the randomness of
82/// *PHYSICAL* RNGs.
83/// \details For more details see Maurer's paper in Journal of Cryptology, 1992.
84class MaurerRandomnessTest : public Bufferless<Sink>
85{
86public:
87 /// \brief Construct a MaurerRandomnessTest
89
90 size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking);
91
92 /// \brief Provides the number of bytes of input is needed by the test
93 /// \return how many more bytes of input is needed by the test
94 // BytesNeeded() returns how many more bytes of input is needed by the test
95 // GetTestValue() should not be called before BytesNeeded()==0
96 unsigned int BytesNeeded() const {return n >= (Q+K) ? 0 : Q+K-n;}
97
98 // returns a number between 0.0 and 1.0, describing the quality of the
99 // random numbers entered
100 double GetTestValue() const;
101
102private:
103 enum {L=8, V=256, Q=2000, K=2000};
104 double sum;
105 unsigned int n;
106 unsigned int tab[V];
107};
108
109NAMESPACE_END
110
111#endif
Interface for the data processing part of block ciphers.
Definition cryptlib.h:861
Interface for buffered transformations.
Definition cryptlib.h:1657
Base class for bufferless filters.
Definition simple.h:120
Linear Congruential Generator (LCG)
Definition rng.h:23
LC_RNG(word32 init_seed)
Construct a Linear Congruential Generator (LCG)
Definition rng.h:27
Maurer's Universal Statistical Test for Random Bit Generators.
Definition rng.h:85
MaurerRandomnessTest()
Construct a MaurerRandomnessTest.
Definition rng.cpp:135
unsigned int BytesNeeded() const
Provides the number of bytes of input is needed by the test.
Definition rng.h:96
size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking)
Input multiple bytes for processing.
Definition rng.cpp:142
Ensures an object is not copyable.
Definition misc.h:241
Interface for random number generators.
Definition cryptlib.h:1440
SecBlock typedef.
Definition secblock.h:1226
ANSI X9.17 RNG.
Definition rng.h:50
void GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size)
Generate random bytes into a BufferedTransformation.
X917RNG(BlockTransformation *cipher, const byte *seed, const byte *deterministicTimeVector=NULL)
Construct a X917RNG.
Pointer that overloads operator ->
Definition smartptr.h:38
unsigned int word32
32-bit unsigned datatype
Definition config_int.h:72
unsigned short word16
16-bit unsigned datatype
Definition config_int.h:69
word64 lword
Large word type.
Definition config_int.h:168
Abstract base classes that provide a uniform interface to this library.
Implementation of BufferedTransformation's attachment interface.
Crypto++ library namespace.
Classes for automatic resource management.