org.cryptacular.util

Class NonceUtil

java.lang.Object

org.cryptacular.util.NonceUtil

public final class NonceUtil
extends java.lang.Object

Utility class for generating secure nonce and initialization vectors.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	NonceUtil() Private constructor of utility class.

Method Summary

Modifier and Type	Method and Description
static org.bouncycastle.crypto.prng.drbg.SP80090DRBG	newRBG(org.bouncycastle.crypto.Digest digest, int length) Creates a new hash-based DRBG instance that uses the given digest as the pseudorandom source.
static org.bouncycastle.crypto.prng.drbg.SP80090DRBG	newRBG(int length) Creates a new DRBG instance based on a SHA-256 digest.
static byte[]	nist80038d(int length) Generates a nonce/IV using the strategy described in NIST SP-800-38d, section 8.2.2, "RBG-based Construction".
static byte[]	nist80063a(org.bouncycastle.crypto.BlockCipher cipher) Generates a random IV according to NIST SP-800-63a, appendix C, method 2 (pseudorandom), suitable for use with any block cipher mode described in that standard.
static byte[]	nist80063a(org.bouncycastle.crypto.BlockCipher cipher, javax.crypto.SecretKey key) Generates a random IV according to NIST SP-800-63a, appendix C, method 1 (encrypted nonce), suitable for use with any block cipher mode described in that standard.
static byte[]	nist80063a(org.bouncycastle.crypto.prng.SP800SecureRandom prng, int blockSize) Generates a random IV according to NIST SP-800-63a, appendix C, method 2 (pseudorandom), suitable for use with any block cipher mode described in that standard.
static byte[]	timestampNonce(int length) Generates a nonce of the given size by repetitively concatenating system timestamps (i.e.

Methods inherited from class java.lang.Object

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

Constructor Detail

NonceUtil

private NonceUtil()

Private constructor of utility class.

Method Detail

timestampNonce

public static byte[] timestampNonce(int length)

Generates a nonce of the given size by repetitively concatenating system timestamps (i.e. System.nanoTime()) up to the required size.

Parameters:

length - Positive number of bytes in nonce.

Returns:

Nonce bytes.

nist80038d

public static byte[] nist80038d(int length)

Generates a nonce/IV using the strategy described in NIST SP-800-38d, section 8.2.2, "RBG-based Construction". The implementation uses a hash-based DRBG based on a SHA-256 digest, and uses random data for all bits of the nonce; that is, the fixed field is null.

This nonce generation strategy is suitable for GCM ciphers.

Parameters:

length - Number of bytes in nonce; MUST be 12 or more.

Returns:

Nonce bytes.

nist80063a

public static byte[] nist80063a(org.bouncycastle.crypto.BlockCipher cipher,
                                javax.crypto.SecretKey key)

Generates a random IV according to NIST SP-800-63a, appendix C, method 1 (encrypted nonce), suitable for use with any block cipher mode described in that standard. This method uses an instance of EncryptedNonce for the implementation.

Parameters:

cipher - Block cipher.

key - Encryption key intended for use with IV.

Returns:

Cipher block size number of random bytes.

See Also:

EncryptedNonce

nist80063a

public static byte[] nist80063a(org.bouncycastle.crypto.prng.SP800SecureRandom prng,
                                int blockSize)

Generates a random IV according to NIST SP-800-63a, appendix C, method 2 (pseudorandom), suitable for use with any block cipher mode described in that standard.

Parameters:

prng - NIST SP800-63a approved pseudorandom number generator.

blockSize - Cipher block size in bytes.

Returns:

Cipher block size number of random bytes.

nist80063a

public static byte[] nist80063a(org.bouncycastle.crypto.BlockCipher cipher)

Generates a random IV according to NIST SP-800-63a, appendix C, method 2 (pseudorandom), suitable for use with any block cipher mode described in that standard. Uses an instance of RBGNonce internally with length equal to block size of given cipher.

Parameters:

cipher - Block cipher.

Returns:

Cipher block size number of random bytes.

See Also:

RBGNonce

newRBG

public static org.bouncycastle.crypto.prng.drbg.SP80090DRBG newRBG(int length)

Creates a new DRBG instance based on a SHA-256 digest.

Parameters:

length - Length in bits of values to be produced by DRBG instance.

Returns:

New DRGB instance.

newRBG

public static org.bouncycastle.crypto.prng.drbg.SP80090DRBG newRBG(org.bouncycastle.crypto.Digest digest,
                                                                   int length)

Creates a new hash-based DRBG instance that uses the given digest as the pseudorandom source.

Parameters:

digest - Digest algorithm.

length - Length in bits of values to be produced by DRBG instance.

Returns:

New DRGB instance.