Crypto++  5.6.3
Free C++ class library of cryptographic schemes
Public Member Functions | List of all members
RandomNumberGenerator Class Reference

Interface for random number generators. More...

+ Inheritance diagram for RandomNumberGenerator:

Public Member Functions

virtual void IncorporateEntropy (const byte *input, size_t length)
 Update RNG state with additional unpredictable values. More...
 
virtual bool CanIncorporateEntropy () const
 Determines if a generator can accept additional entropy. More...
 
virtual byte GenerateByte ()
 Generate new random byte and return it. More...
 
virtual unsigned int GenerateBit ()
 Generate new random bit and return it. More...
 
virtual word32 GenerateWord32 (word32 min=0, word32 max=0xffffffffUL)
 Generate a random 32 bit word in the range min to max, inclusive. More...
 
virtual void GenerateBlock (byte *output, size_t size)
 Generate random array of bytes. More...
 
virtual void GenerateIntoBufferedTransformation (BufferedTransformation &target, const std::string &channel, lword length)
 Generate random bytes into a BufferedTransformation. More...
 
virtual void DiscardBytes (size_t n)
 Generate and discard n bytes. More...
 
template<class IT >
void Shuffle (IT begin, IT end)
 Randomly shuffle the specified array. More...
 
- Public Member Functions inherited from Algorithm
 Algorithm (bool checkSelfTestStatus=true)
 Interface for all crypto algorithms. More...
 
virtual std::string AlgorithmName () const
 Provides the name of this algorithm. More...
 
- Public Member Functions inherited from Clonable
virtual ClonableClone () const
 Copies this object. More...
 

Detailed Description

Interface for random number generators.

The library provides a number of random number generators, from software based to hardware based generators.

All generated values are uniformly distributed over the range specified.

Definition at line 1176 of file cryptlib.h.

Member Function Documentation

virtual void RandomNumberGenerator::IncorporateEntropy ( const byte *  input,
size_t  length 
)
inlinevirtual

Update RNG state with additional unpredictable values.

Parameters
inputthe entropy to add to the generator
lengththe size of the input buffer
Exceptions
NotImplemented

A generator may or may not accept additional entropy. Call CanIncorporateEntropy() to test for the ability to use additional entropy.

If a derived class does not override IncorporateEntropy(), then the base class throws NotImplemented.

Reimplemented in ClassNullRNG, AutoSeededX917RNG< BLOCK_CIPHER >, RDSEED, RDRAND, and RandomPool.

Definition at line 1187 of file cryptlib.h.

virtual bool RandomNumberGenerator::CanIncorporateEntropy ( ) const
inlinevirtual

Determines if a generator can accept additional entropy.

Returns
true if IncorporateEntropy() is implemented

Reimplemented in ClassNullRNG, AutoSeededX917RNG< BLOCK_CIPHER >, and RandomPool.

Definition at line 1195 of file cryptlib.h.

byte RandomNumberGenerator::GenerateByte ( )
virtual

Generate new random byte and return it.

Returns
a random 8-bit byte

Default implementation calls GenerateBlock() with one byte.

All generated values are uniformly distributed over the range specified within the the contraints of a particular generator.

Reimplemented in ClassNullRNG, and PublicBlumBlumShub.

Definition at line 294 of file cryptlib.cpp.

unsigned int RandomNumberGenerator::GenerateBit ( )
virtual

Generate new random bit and return it.

Returns
a random bit

The default implementation calls GenerateByte() and return its lowest bit.

All generated values are uniformly distributed over the range specified within the the contraints of a particular generator.

Reimplemented in ClassNullRNG, and PublicBlumBlumShub.

Definition at line 289 of file cryptlib.cpp.

word32 RandomNumberGenerator::GenerateWord32 ( word32  min = 0,
word32  max = 0xffffffffUL 
)
virtual

Generate a random 32 bit word in the range min to max, inclusive.

Parameters
minthe lower bound of the range
maxthe upper bound of the range
Returns
a random 32-bit word

The default implementation calls Crop() on the difference between max and min, and then returns the result added to min.

All generated values are uniformly distributed over the range specified within the the contraints of a particular generator.

Reimplemented in ClassNullRNG, and MersenneTwister< K, M, N, F, S >.

Definition at line 301 of file cryptlib.cpp.

void RandomNumberGenerator::GenerateBlock ( byte *  output,
size_t  size 
)
virtual

Generate random array of bytes.

Parameters
outputthe byte buffer
sizethe length of the buffer, in bytes

All generated values are uniformly distributed over the range specified within the the contraints of a particular generator.

Note
A derived generator must override either GenerateBlock() or GenerateIntoBufferedTransformation(). They can override both, or have one call the other.

Reimplemented in KDF2_RNG, ClassNullRNG, RDSEED, AdditiveCipherTemplate< BASE >, AdditiveCipherTemplate< AbstractPolicyHolder< AdditiveCipherAbstractPolicy, CTR_ModePolicy > >, BlockingRng, NonblockingRng, RDRAND, FixedRNG, MersenneTwister< K, M, N, F, S >, LC_RNG, Weak::ARC4_Base, and PublicBlumBlumShub.

Definition at line 329 of file cryptlib.cpp.

void RandomNumberGenerator::GenerateIntoBufferedTransformation ( BufferedTransformation target,
const std::string &  channel,
lword  length 
)
virtual

Generate random bytes into a BufferedTransformation.

Parameters
targetthe BufferedTransformation object which receives the bytes
channelthe channel on which the bytes should be pumped
lengththe number of bytes to generate

The default implementation calls GenerateBlock() and pumps the result into the DEFAULT_CHANNEL of the target.

All generated values are uniformly distributed over the range specified within the the contraints of a particular generator.

Note
A derived generator must override either GenerateBlock() or GenerateIntoBufferedTransformation(). They can override both, or have one call the other.

Reimplemented in ClassNullRNG, AutoSeededX917RNG< BLOCK_CIPHER >, X917RNG, and RandomPool.

Definition at line 347 of file cryptlib.cpp.

void RandomNumberGenerator::DiscardBytes ( size_t  n)
virtual

Generate and discard n bytes.

Parameters
nthe number of bytes to generate and discard

Reimplemented in ClassNullRNG, RDSEED, MersenneTwister< K, M, N, F, S >, RDRAND, and Weak::ARC4_Base.

Definition at line 342 of file cryptlib.cpp.

template<class IT >
void RandomNumberGenerator::Shuffle ( IT  begin,
IT  end 
)
inline

Randomly shuffle the specified array.

Parameters
beginan iterator to the first element in the array
endan iterator beyond the last element in the array

The resulting permutation is uniformly distributed.

Definition at line 1250 of file cryptlib.h.


The documentation for this class was generated from the following files: