gnu.crypto.prng

Interface IRandom

public interface IRandom extends Cloneable

The basic visible methods of any pseudo-random number generator.

The [HAC] defines a PRNG (as implemented in this library) as follows:

IMPLEMENTATION NOTE: Although all the concrete classes in this package implement the Cloneable interface, it is important to note here that such an operation, for those algorithms that use an underlting symmetric key block cipher, DOES NOT clone any session key material that may have been used in initialising the source PRNG (the instance to be cloned). Instead a clone of an already initialised PRNG, that uses and underlying symmetric key block cipher, is another instance with a clone of the same cipher that operates with the same block size but without any knowledge of neither key material nor key size.

References:

  1. [HAC]: Handbook of Applied Cryptography.
    CRC Press, Inc. ISBN 0-8493-8523-7, 1997
    Menezes, A., van Oorschot, P. and S. Vanstone.

Version: $Revision: 1.12 $

Method Summary
voidaddRandomByte(byte b)

Supplement, or possibly replace, the random state of this PRNG with a random byte.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

voidaddRandomBytes(byte[] in)

Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

voidaddRandomBytes(byte[] in, int offset, int length)

Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

Objectclone()

Returns a clone copy of this instance.

voidinit(Map attributes)

Initialises the pseudo-random number generator scheme with the appropriate attributes.

Stringname()

Returns the canonical name of this instance.

bytenextByte()

Returns the next 8 bits of random data generated from this instance.

voidnextBytes(byte[] out, int offset, int length)

Fills the designated byte array, starting from byte at index offset, for a maximum of length bytes with the output of this generator instance.

Method Detail

addRandomByte

public void addRandomByte(byte b)

Supplement, or possibly replace, the random state of this PRNG with a random byte.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

Parameters: b The byte to add.

addRandomBytes

public void addRandomBytes(byte[] in)

Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

Parameters: in The buffer of new random bytes to add.

addRandomBytes

public void addRandomBytes(byte[] in, int offset, int length)

Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

Parameters: in The buffer of new random bytes to add. offset The offset from whence to begin reading random bytes. length The number of random bytes to add.

Throws: IndexOutOfBoundsException If offset, length, or offset+length is out of bounds.

clone

public Object clone()

Returns a clone copy of this instance.

Returns: a clone copy of this instance.

init

public void init(Map attributes)

Initialises the pseudo-random number generator scheme with the appropriate attributes.

Parameters: attributes a set of name-value pairs that describe the desired future instance behaviour.

Throws: IllegalArgumentException if at least one of the defined name/ value pairs contains invalid data.

name

public String name()

Returns the canonical name of this instance.

Returns: the canonical name of this instance.

nextByte

public byte nextByte()

Returns the next 8 bits of random data generated from this instance.

Returns: the next 8 bits of random data generated from this instance.

Throws: IllegalStateException if the instance is not yet initialised. LimitReachedException if this instance has reached its theoretical limit for generating non-repetitive pseudo-random data.

nextBytes

public void nextBytes(byte[] out, int offset, int length)

Fills the designated byte array, starting from byte at index offset, for a maximum of length bytes with the output of this generator instance.

Parameters: out the placeholder to contain the generated random bytes. offset the starting index in out to consider. This method does nothing if this parameter is not within 0 and out.length. length the maximum number of required random bytes. This method does nothing if this parameter is less than 1.

Throws: IllegalStateException if the instance is not yet initialised. LimitReachedException if this instance has reached its theoretical limit for generating non-repetitive pseudo-random data.

Copyright © 2001, 2002, 2003 Free Software Foundation, Inc. All Rights Reserved.