com.netscape.cmsutil.util

Class HMACDigest

java.lang.Object

com.netscape.cmsutil.util.HMACDigest

All Implemented Interfaces:

java.lang.Cloneable

public class HMACDigest
extends java.lang.Object
implements java.lang.Cloneable

This class implements the HMAC algorithm specified in RFC 2104 using any MessageDigest.

Version:

$Revision$, $Date$

Author:

mikep

See Also:

MessageDigest

Field Summary

Fields

Modifier and Type	Field and Description
static int	IPAD
static int	OPAD
static int	PAD_BYTES

Constructor Summary

Constructors

Constructor and Description
HMACDigest(java.security.MessageDigest md) Creates an HMACDigest
HMACDigest(java.security.MessageDigest md, byte[] key) Creates an HMACDigest and initializes the HMAC function with the given key.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	clone() Clone the HMACDigest
byte[]	digest() Completes the HMAC computation with the outer pad The digest is reset after this call is made.
java.security.MessageDigest	getMessageDigest() Return the MessageDigest used for this HMAC
void	init(byte[] key) Initialize the HMAC function The HMAC transform looks like: hash(key XOR opad, hash(key XOR ipad, text)) where key is an n byte key ipad is the byte 0x36 repeated 64 times opad is the byte 0x5c repeated 64 times and text is the data being protected This routine must be called after every reset.
void	reset() Resets the digest for further use.
void	update(byte[] input) Updates the digest using the specified array of bytes.

Methods inherited from class java.lang.Object

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

Field Detail

PAD_BYTES

public static final int PAD_BYTES

See Also:

Constant Field Values

IPAD

public static final int IPAD

See Also:

Constant Field Values

OPAD

public static final int OPAD

See Also:

Constant Field Values

Constructor Detail

HMACDigest

public HMACDigest(java.security.MessageDigest md)

Creates an HMACDigest

Parameters:

md - The MessageDigest to be used for the HMAC calculation. It must be clonable.

HMACDigest

public HMACDigest(java.security.MessageDigest md,
                  byte[] key)

Creates an HMACDigest and initializes the HMAC function with the given key.

Parameters:

md - The MessageDigest to be used for the HMAC calculation. It must be clonable.

key - The key value to be used in the HMAC calculation

Method Detail

getMessageDigest

public java.security.MessageDigest getMessageDigest()

Return the MessageDigest used for this HMAC

init

public void init(byte[] key)

Initialize the HMAC function The HMAC transform looks like: hash(key XOR opad, hash(key XOR ipad, text)) where key is an n byte key ipad is the byte 0x36 repeated 64 times opad is the byte 0x5c repeated 64 times and text is the data being protected This routine must be called after every reset.

Parameters:

key - The password used to protect the hash value

update

public void update(byte[] input)

Updates the digest using the specified array of bytes.

Parameters:

input - the array of bytes.

digest

public byte[] digest()

Completes the HMAC computation with the outer pad The digest is reset after this call is made.

Returns:

the array of bytes for the resulting hash value.

reset

public void reset()

Resets the digest for further use.

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Clone the HMACDigest

Overrides:

clone in class java.lang.Object

Returns:

a clone if the implementation is cloneable.

Throws:

java.lang.CloneNotSupportedException - if this is called on a MessageDigest implementation that does not support Cloneable.