iaik.security.mac

Class CMac

java.lang.Object

javax.crypto.MacSpi

iaik.security.mac.CMac

Direct Known Subclasses:

CMacAES, CMacDESede

public abstract class CMac
extends javax.crypto.MacSpi

This class implements a MAC based on a block cipher as specified in NIST Special Publication 800-38B.

This base class can support block ciphers with a block size of 64 bit and 128 bit.

The MAC length (Tlen) is the block size of the underlying cipher.

Method Summary

Methods

Modifier and Type	Method and Description
protected byte[]	engineDoFinal() Calculate the MAC and reset this MAC object to be ready for further MAC calculations.
protected int	engineGetMacLength()
protected void	engineInit(java.security.Key key, java.security.spec.AlgorithmParameterSpec params) Initialize the MAC with the given key.
protected void	engineReset() Reset this MAC object to be ready for a new MAC computation.
protected void	engineUpdate(byte input) Feed a single byte into the MAC.
protected void	engineUpdate(byte[] input, int offset, int len) Feed in a block of bytes into this MAC.

Methods inherited from class javax.crypto.MacSpi

clone, engineUpdate

Methods inherited from class java.lang.Object

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

Method Detail

engineGetMacLength

protected int engineGetMacLength()

Specified by:

engineGetMacLength in class javax.crypto.MacSpi

Returns:

The MAC length in bytes, which is the block size of the underlying cipher.

engineInit

protected void engineInit(java.security.Key key,
              java.security.spec.AlgorithmParameterSpec params)
                   throws java.security.InvalidKeyException,
                          java.security.InvalidAlgorithmParameterException

Initialize the MAC with the given key.

Specified by:

engineInit in class javax.crypto.MacSpi

Parameters:

key - The MAC key.

params - This implementation ignores this parameter.

Throws:

java.security.InvalidKeyException

java.security.InvalidAlgorithmParameterException

engineUpdate

protected void engineUpdate(byte input)

Feed a single byte into the MAC.

For better performance, use engineUpdate(byte[], int, int) and feed in larger blocks.

Specified by:

engineUpdate in class javax.crypto.MacSpi

Parameters:

input - The input byte.

engineUpdate

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

Feed in a block of bytes into this MAC.

Specified by:

engineUpdate in class javax.crypto.MacSpi

Parameters:

input - The data buffer.

offset - The start index in the buffer.

len - The length of the data block in the buffer.

engineDoFinal

protected byte[] engineDoFinal()

Calculate the MAC and reset this MAC object to be ready for further MAC calculations.

Specified by:

engineDoFinal in class javax.crypto.MacSpi

Returns:

The MAC value.

engineReset

protected void engineReset()

Reset this MAC object to be ready for a new MAC computation.

Specified by:

engineReset in class javax.crypto.MacSpi