iaik.security.md

Class KECCAK256

java.lang.Object

java.security.MessageDigestSpi

java.security.MessageDigest

iaik.security.md.KECCAK256

All Implemented Interfaces:

java.lang.Cloneable

public final class KECCAK256
extends java.security.MessageDigest

This class implements the KECCAK message digest algorithm.

The KECCAK-256 message digest algorithm produces a 256-bit hash-value of the given input data. Notice that KECCAK-256 slightly differs from the final NIST approved SHA3-256 message digest algorithm and therefore is not output compatible to SHA3-256!

This class extends the java.security.MessageDigest class and applications should use one of the getInstance methods presented there to create a MessageDigest-KECCAK object. Generally, an application wishing to compute the message digest of some data has to perform three steps:

• First an instance of the desired message digest algorithm has to be created using a proper getInstance method, e.g.:

   MessageDigest KECCAK = MessageDigest.getInstance("KECCAK256");
   

• Second, the data to be hashed is supplied to the MessageDigest object just created by one or more calls to one of the update methods, e.g:
  

       KECCAK.update(m1);
       KECCAK.update(m2);
       ...
   

• Finally, the hash value can be computed using one of the digest methods:
  

   byte[] hash_value = KECCAK.digest();
   

There are several ways for combining update and digest methods for computing a message digest. Since this class implements the Cloneable interface, KECCAK MessageDigest objects may be used for compute intermediate hashes through cloning (see http ://java.sun.com/products/JDK/1.2/docs/guide/security/CryptoSpec.html).

When the hash value successfully has been computed, the KECCAK MessageDigest object automatically resets for being able to be supplied with new data to be hashed..

See Also:

MessageDigest

Constructor Summary

Constructors

Constructor and Description
KECCAK256() Default constructor.

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.Object	clone()
protected void	doPadding()
protected void	engineCompress(byte[] input, int offset)
protected byte[]	engineDigest()
protected void	engineDigest(byte[] output, int offset)
protected int	engineDigest(byte[] buf, int offset, int len) Calculates the digest value and writes it to the given output buffer.
protected int	engineGetDigestLength()
protected void	engineReset()
protected void	engineUpdate(byte input)
protected void	engineUpdate(byte[] input, int offset, int len)

Methods inherited from class java.security.MessageDigest

digest, digest, digest, getAlgorithm, getDigestLength, getInstance, getInstance, getInstance, getProvider, isEqual, reset, toString, update, update, update, update

Methods inherited from class java.security.MessageDigestSpi

engineUpdate

Methods inherited from class java.lang.Object

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

Constructor Detail

KECCAK256

public KECCAK256()

Default constructor.

Method Detail

engineGetDigestLength

protected int engineGetDigestLength()

Overrides:

engineGetDigestLength in class java.security.MessageDigestSpi

engineCompress

protected void engineCompress(byte[] input,
                  int offset)

doPadding

protected void doPadding()

engineDigest

protected void engineDigest(byte[] output,
                int offset)

engineDigest

protected byte[] engineDigest()

Specified by:

engineDigest in class java.security.MessageDigestSpi

engineDigest

protected int engineDigest(byte[] buf,
               int offset,
               int len)
                    throws java.security.DigestException

Calculates the digest value and writes it to the given output buffer.

Overrides:

engineDigest in class java.security.MessageDigestSpi

Parameters:

buf - the output buffer in which to write the digest

offset - the start offset in the output buffer

len - the length of the digest value.

Returns:

the length of the digest written to the output buffer.

Throws:

java.security.DigestException - if an error occurs when calculating the digest value.

engineUpdate

protected void engineUpdate(byte input)

Specified by:

engineUpdate in class java.security.MessageDigestSpi

engineUpdate

protected void engineUpdate(byte[] input,
                int offset,
                int len)

Specified by:

engineUpdate in class java.security.MessageDigestSpi

engineReset

protected void engineReset()

Specified by:

engineReset in class java.security.MessageDigestSpi

clone

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

Overrides:

clone in class java.security.MessageDigest

Throws:

java.lang.CloneNotSupportedException