iaik.security.md

Class SHA3_256

java.lang.Object

java.security.MessageDigestSpi

java.security.MessageDigest

iaik.security.md.SHA3_256

All Implemented Interfaces:

java.lang.Cloneable

public final class SHA3_256
extends java.security.MessageDigest

This class implements the SHA-3 message digest algorithm for calculating a 256-bit hash value.

NIST (FIPS PUB 202) specifies the Secure Hash Algorithm-3 (SHA-3) family of message digest algorithms as supplement of the SHA-1 and SHA-2 message digest algorithm family. SHA-3 is based on the KECCAK message digest algorithm but is not fully identical to KECCAK because it adds a suffix to the message to ensure domain separation between the SHA-3 hash function and the newly specified SHA-3 extendable-output function (XOF). The XOF allows the output to be extended to any desired length.

This class implements the SHA3-256 hash function that produces a 256-bit hash-value of the given input data. Since SHA3-256 and KECCAK256 are not identical a SHA3-256 MessageDigest engine will produce a different output than a KECCAK256 MessageDigest engine. To ensure to use the NIST standardized version, specify SHA3-256 as algorithm name when instantiating a SHA3-256 MessageDigest engine:

 MessageDigest sha3 = MessageDigest.getInstance("SHA3-256");
 

After having created the MessageDigest engine, you can supply the data to be hashed by one or more calls to one of the update methods, e.g:

     sha3.update(m1);
     sha3.update(m2);
     ...
 

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

 byte[] hash_value = sha3.digest();
 

There are several ways for combining update and digest methods for computing a message digest. When the hash value successfully has been computed, the SHA-3 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
SHA3_256() 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

SHA3_256

public SHA3_256()

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