gnu.java.security.prng
Interface IRandom
- Cloneable
- ARCFour, BasePRNG, CSPRNG, Fortuna, Fortuna.Generator, ICMGenerator, MDGenerator, PBKDF2, UMacGenerator
The basic visible methods of any pseudo-random number generator.
The [HAC] defines a PRNG (as implemented in this library) as follows:
- "5.6 Definition: A pseudorandom bit generator (PRBG) is said to pass the
next-bit test if there is no polynomial-time algorithm which, on
input of the first
L bits of an output sequence S,
can predict the (L+1)st bit of S with a
probability significantly greater than 1/2." - "5.8 Definition: A PRBG that passes the next-bit test
(possibly under some plausible but unproved mathematical assumption such as
the intractability of factoring integers) is called a cryptographically
secure pseudorandom bit generator (CSPRBG)."
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 underlying
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 an
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:
- [HAC]: Handbook of
Applied Cryptography.
CRC Press, Inc. ISBN 0-8493-8523-7, 1997
Menezes, A., van Oorschot, P. and S. Vanstone.
void | addRandomByte(byte b)- Supplement, or possibly replace, the random state of this PRNG with a
random byte.
|
void | addRandomBytes(byte[] in)- Supplement, or possibly replace, the random state of this PRNG with a
sequence of new random bytes.
|
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.
|
Object | clone()- Returns a clone copy of this instance.
|
void | init(Map<K,V> attributes)- Initialises the pseudo-random number generator scheme with the appropriate
attributes.
|
String | name()- Returns the canonical name of this instance.
|
byte | nextByte()- Returns the next 8 bits of random data generated from this instance.
|
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.
|
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.
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.
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.
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.
init
public void init(Map<K,V> attributes)
Initialises the pseudo-random number generator scheme with the appropriate
attributes.
attributes - a set of name-value pairs that describe the desired
future instance behaviour.
name
public String name()
Returns the canonical name of this instance.
- the canonical name of this instance.
nextBytes
public void nextBytes(byte[] out,
int offset,
int length)
throws IllegalStateException,
LimitReachedException Fills the designated byte array, starting from byte at index
offset, for a maximum of length bytes with
the output of this generator instance.
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.
IRandom.java --
Copyright (C) 2001, 2002, 2003, 2006 Free Software Foundation, Inc.
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