OldRandomPool Class Reference

Randomness Pool based on PGP 2.6.x with MDC. More...

`#include <randpool.h>`

Inheritance diagram for OldRandomPool:

## Public Member Functions

| OldRandomPool (unsigned int poolSize=384)
| Construct an OldRandomPool.
bool | CanIncorporateEntropy () const
| Determines if a generator can accept additional entropy.
void | IncorporateEntropy (const byte *input, size_t length)
| Update RNG state with additional unpredictable values.
void | GenerateIntoBufferedTransformation (BufferedTransformation &target, const std::string &channel, lword size)
| Generate random bytes into a BufferedTransformation.
byte | GenerateByte ()
| Generate new random byte and return it.
void | GenerateBlock (byte *output, size_t size)
| Generate random array of bytes.
word32 | GenerateWord32 (word32 min=0, word32 max=0xffffffffUL)
| Generate a random 32 bit word in the range min to max, inclusive.
Public Member Functions inherited from RandomNumberGenerator
virtual unsigned int | GenerateBit ()
| Generate new random bit and return it.
virtual void | DiscardBytes (size_t n)
| Generate and discard n bytes.
template<class IT>
void | Shuffle (IT begin, IT end)
| Randomly shuffle the specified array.
Public Member Functions inherited from Algorithm
| Algorithm (bool checkSelfTestStatus=true)
| Interface for all crypto algorithms.
virtual std::string | AlgorithmName () const
| Provides the name of this algorithm.
virtual std::string | AlgorithmProvider () const
| Retrieve the provider of this algorithm.
Public Member Functions inherited from Clonable
virtual Clonable * | Clone () const
| Copies this object.

## Detailed Description

Randomness Pool based on PGP 2.6.x with MDC.

If you need the pre-Crypto++ 5.5 generator then use OldRandomPool class. The OldRandomPool also provides the modern interface, including CanIncorporateEntropy, IncorporateEntropy and GenerateIntoBufferedTransformation.

You should reseed the generator after a fork() to avoid multiple generators with the same internal state.

You should migrate away from OldRandomPool at the earliest opportunity. Use a modern random number generator or key derivation function, like AutoSeededRandomPool or HKDF.

Warning
  This class uses an old style PGP 2.6.x with MDC. The generator risks reusing random numbers after state rollback. You should migrate away from OldRandomPool at the earliest opportunity.

See also
  RandomPool, AutoSeededRandomPool, HKDF, P1363_KDF2, PKCS12_PBKDF, PKCS5_PBKDF2_HMAC

Since
  Crypto++ 6.0

Definition at line 74 of file randpool.h.

## Constructor & Destructor Documentation

## OldRandomPool()

OldRandomPool::OldRandomPool | ( | unsigned int | poolSize = 384 | ) |

Construct an OldRandomPool.

Parameters

  poolSize | internal pool size of the generator

poolSize must be greater than 16

## Member Function Documentation

## CanIncorporateEntropy()

bool OldRandomPool::CanIncorporateEntropy | ( |  | ) | const

inline virtual

Determines if a generator can accept additional entropy.

Returns
  true if IncorporateEntropy() is implemented

Reimplemented from RandomNumberGenerator.

Definition at line 83 of file randpool.h.

## IncorporateEntropy()

void OldRandomPool::IncorporateEntropy | ( | const byte * | input,
|  | size_t | length )

virtual

Update RNG state with additional unpredictable values.

Parameters

  input | the entropy to add to the generator
  length | the 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 from RandomNumberGenerator.

## GenerateIntoBufferedTransformation()

void OldRandomPool::GenerateIntoBufferedTransformation | ( | BufferedTransformation & | target,
|  | const std::string & | channel,
|  | lword | length )

virtual

Generate random bytes into a BufferedTransformation.

Parameters

  target | the BufferedTransformation object which receives the bytes
  channel | the channel on which the bytes should be pumped
  length | the 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 constraints 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 from RandomNumberGenerator.

## GenerateByte()

byte OldRandomPool::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 constraints of a particular generator.

Reimplemented from RandomNumberGenerator.

## GenerateBlock()

void OldRandomPool::GenerateBlock | ( | byte * | output,
|  | size_t | size )

virtual

Generate random array of bytes.

Parameters

  output | the byte buffer
  size | the length of the buffer, in bytes

All generated values are uniformly distributed over the range specified within the the constraints 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 from RandomNumberGenerator.

## GenerateWord32()

word32 OldRandomPool::GenerateWord32 | ( | word32 | min = 0,
|  | word32 | max = 0xffffffffUL )

virtual

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

Parameters

  min | the lower bound of the range
  max | the 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 constraints of a particular generator.

Reimplemented from RandomNumberGenerator.

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

- randpool.h