org.cryptacular.generator.sp80038d

Class RBGNonce

java.lang.Object

org.cryptacular.generator.sp80038d.RBGNonce

All Implemented Interfaces:

Nonce

public class RBGNonce
extends java.lang.Object
implements Nonce

RBG-based nonce generation strategy that uses a RBG component to produce values for the invocation field as described in NIST SP-800-38D, section 8.2.2.

NOTE: users of this class are responsible for counting number of invocations and enforcing the constraints described in section 8.3; namely the following:

The total number of invocations of the authenticated encryption function shall not exceed 2³², including all IV lengths and all instances of the authenticated encryption function with the given key.

Instances of this class are thread safe.

Field Summary

Fields

Modifier and Type	Field and Description
private byte[]	fixed Fixed field value.
private int	randomLength Number of bytes of random data in invocation field.
private org.bouncycastle.crypto.prng.drbg.SP80090DRBG	rbg Random bit generator.

Constructor Summary

Constructors

Constructor and Description
RBGNonce() Creates a new instance that produces 12-bytes (96-bits) of random data; that is, the fixed field of the nonce is null.
RBGNonce(int randomLength) Creates a new instance that produces length bytes of random data; that is, the fixed field of the nonce is null.
RBGNonce(java.lang.String fixed, int randomLength) Creates a new instance using the given fixed field value.

Method Summary

Modifier and Type	Method and Description
byte[]	generate() Generates a nonce value.
int	getLength()
private static org.bouncycastle.crypto.prng.drbg.SP80090DRBG	newRBG(int length, byte[] domain) Creates a new DRBG instance.

Methods inherited from class java.lang.Object

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

Field Detail

fixed

private final byte[] fixed

Fixed field value.

randomLength

private final int randomLength

Number of bytes of random data in invocation field.

rbg

private final org.bouncycastle.crypto.prng.drbg.SP80090DRBG rbg

Random bit generator.

Constructor Detail

RBGNonce

public RBGNonce()

Creates a new instance that produces 12-bytes (96-bits) of random data; that is, the fixed field of the nonce is null.

RBGNonce

public RBGNonce(int randomLength)

Creates a new instance that produces length bytes of random data; that is, the fixed field of the nonce is null.

Parameters:

randomLength - Number of bytes in the random part of the nonce. MUST be at least 12.

RBGNonce

public RBGNonce(java.lang.String fixed,
                int randomLength)

Creates a new instance using the given fixed field value.

Parameters:

fixed - User-defined fixed field value.

randomLength - Number of bytes in the random part of the nonce. MUST be at least 12.

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.

newRBG

private static org.bouncycastle.crypto.prng.drbg.SP80090DRBG newRBG(int length,
                                                                    byte[] domain)

Creates a new DRBG instance.

Parameters:

length - Length in bits of values produced by DRBG.

domain - Domain qualifier.

Returns:

New DRBG instance.