gnu.crypto.mac

Class OMAC

Implemented Interfaces:
IMac

public class OMAC
extends Object
implements IMac

The One-Key CBC MAC, OMAC. This message authentication code is based on a block cipher in CBC mode.

References:

  1. Tetsu Iwata and Kaoru Kurosawa, OMAC: One-Key CBC MAC.

Fields inherited from interface gnu.crypto.mac.IMac

MAC_KEY_MATERIAL, TRUNCATED_SIZE

Constructor Summary

OMAC(IBlockCipher cipher)

Method Summary

Object
clone()
Returns a clone copy of this instance.
byte[]
digest()
Completes the MAC by performing final operations such as padding and resetting the instance.
void
digest(byte[] out, int off)
void
init(Map attrib)
Initialises the algorithm with designated attributes.
int
macSize()
Returns the output length in bytes of this MAC algorithm.
String
name()
Returns the canonical name of this algorithm.
void
reset()
Resets the algorithm instance for re-initialisation and use with other characteristics.
boolean
selfTest()
A basic test.
void
update(byte b)
Continues a MAC operation using the input byte.
void
update(byte[] buf, int off, int len)
Continues a MAC operation, by filling the buffer, processing data in the algorithm's MAC_SIZE-bit block(s), updating the context and count, and buffering the remaining bytes in buffer for the next operation.

Constructor Details

OMAC

public OMAC(IBlockCipher cipher)

Method Details

clone

public Object clone()
Returns a clone copy of this instance.
Specified by:
clone in interface IMac
Returns:
a clone copy of this instance.

digest

public byte[] digest()
Completes the MAC by performing final operations such as padding and resetting the instance.
Specified by:
digest in interface IMac
Returns:
the array of bytes representing the MAC value.

digest

public void digest(byte[] out,
                   int off)

init

public void init(Map attrib)
            throws InvalidKeyException
Initialises the algorithm with designated attributes. Permissible names and values are described in the class documentation above.
Specified by:
init in interface IMac
Parameters:

macSize

public int macSize()
Returns the output length in bytes of this MAC algorithm.
Specified by:
macSize in interface IMac
Returns:
the output length in bytes of this MAC algorithm.

name

public String name()
Returns the canonical name of this algorithm.
Specified by:
name in interface IMac
Returns:
the canonical name of this algorithm.

reset

public void reset()
Resets the algorithm instance for re-initialisation and use with other characteristics. This method always succeeds.
Specified by:
reset in interface IMac

selfTest

public boolean selfTest()
A basic test. Ensures that the MAC of a pre-determined message is equal to a known pre-computed value.
Specified by:
selfTest in interface IMac
Returns:
true if the implementation passes a basic self-test. Returns false otherwise.

update

public void update(byte b)
Continues a MAC operation using the input byte.
Specified by:
update in interface IMac
Parameters:
b - the input byte to digest.

update

public void update(byte[] buf,
                   int off,
                   int len)
Continues a MAC operation, by filling the buffer, processing data in the algorithm's MAC_SIZE-bit block(s), updating the context and count, and buffering the remaining bytes in buffer for the next operation.
Specified by:
update in interface IMac
Parameters:

Copyright © 2001, 2002, 2003 Free Software Foundation, Inc. All Rights Reserved.