org.cryptacular.generator.sp80038a

Class BigIntegerCounterNonce

java.lang.Object

org.cryptacular.generator.sp80038a.BigIntegerCounterNonce

All Implemented Interfaces:

Nonce

public class BigIntegerCounterNonce
extends java.lang.Object
implements Nonce

Uses a BigInteger to back a counter in order to produce nonces of arbitrary length.

A common use case for this component is creation of IVs for ciphers with 16-byte block size, e.g. AES.

Instances of this class are thread safe.

Field Summary

Fields

Modifier and Type	Field and Description
private java.math.BigInteger	counter Counter.
private int	length Length of generated counter nonce values in bytes.

Constructor Summary

Constructors

Constructor and Description
BigIntegerCounterNonce(java.math.BigInteger counter, int length) Creates a new instance with given parameters.

Method Summary

Modifier and Type	Method and Description
byte[]	generate() Generates a nonce value.
int	getLength()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

counter

private java.math.BigInteger counter

Counter.

length

private final int length

Length of generated counter nonce values in bytes.

Constructor Detail

BigIntegerCounterNonce

public BigIntegerCounterNonce(java.math.BigInteger counter,
                              int length)

Creates a new instance with given parameters.

Parameters:

counter - Initial counter value.

length - Maximum length of generated counter values in bytes.

Method Detail

generate

public byte[] generate()
                throws LimitException

Description copied from interface: Nonce

Generates a nonce value.

Specified by:

generate in interface Nonce

Returns:

Nonce bytes.

Throws:

LimitException - When a limit imposed by the nonce generation strategy, if any, is exceeded.

getLength

public int getLength()

Specified by:

getLength in interface Nonce

Returns:

Length in bytes of generated nonce values.