iaik.me.security.md
Class SHA256

java.lang.Object
  |
  +--iaik.me.security.MessageDigest
        |
        +--iaik.me.security.md.SHA256

Direct Known Subclasses:

SHA224

public class SHA256

extends MessageDigest

This class implements the 32-bit hash algorithm SHA-256 from NIST (FIPS PUB 186-2).

Version:

File Revision 2

See Also:

java.security.MessageDigest, SHA224

Fields inherited from class iaik.me.security.MessageDigest

buffer, count, digestLength, padding

Constructor Summary

SHA256()
Construct a new SHA-256 message digest.

Method Summary

Object	clone() Returns a clone of this SHA256 Object.
protected void	compress(byte[] input, int offset) The heart of this hash algorithm--the compression function.
int	digest(byte[] output, int offset) Get digest value of the hash, but do not reset the hash automatically.
byte[][]	getEncodedDigestInfo() Returns the pregenerated ASN1 encoding of the DigestInfo structure for the corresponding digest algorithm, see .
void	reset() Resets this SHA256 message digest object for being supplied with new data.

Methods inherited from class iaik.me.security.MessageDigest

digest, digest, getAlgorithm, getDigestLength, getInstance, register, update, update, update

Methods inherited from class java.lang.Object

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

Constructor Detail

SHA256

public SHA256()

Construct a new SHA-256 message digest.

Method Detail

clone

public Object clone()

Returns a clone of this SHA256 Object.

Overrides:

clone in class MessageDigest

Returns:

a clone of this SHA256 Object

reset

public void reset()

Resets this SHA256 message digest object for being supplied with new data.

This method is called by digest(byte[], int) after the actual hash computation has been finished to automatically reset the message digest object for being supplied with new data for starting a new hash computation.

Overrides:

reset in class MessageDigest

See Also:

java.security.MessageDigest#digest

digest

public int digest(byte[] output,
                  int offset)

Get digest value of the hash, but do not reset the hash automatically. offset + digestlength < output.

Overrides:

digest in class MessageDigest

Parameters:

output - The buffer where to put the hash value.

offset - The offset in the buffer where to start writing the hash.

compress

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

The heart of this hash algorithm--the compression function.

Overrides:

compress in class MessageDigest

Parameters:

input - The input data.

offset - The offset where the input block starts.

getEncodedDigestInfo

public byte[][] getEncodedDigestInfo()

Description copied from class: MessageDigest

Returns the pregenerated ASN1 encoding of the DigestInfo structure for the corresponding digest algorithm, see . The digest value is of course NOT included. The two dimensional array cotains the enconding with (index = 0) and without the ASN1 parameter NULL (index = 1).

Overrides:

getEncodedDigestInfo in class MessageDigest

Following copied from class: iaik.me.security.MessageDigest

Returns:

a two dimensional byte array containing the digestinfo encodings