package org.bouncycastle.crypto;
/**
* The base interface for implementations of message authentication codes (MACs).
*/
public interface Mac
{
/**
* Initialise the MAC.
*
* @param params the key and other data required by the MAC.
* @exception IllegalArgumentException if the params argument is
* inappropriate.
*/
public void init(CipherParameters params)
throws IllegalArgumentException;
/**
* Return the name of the algorithm the MAC implements.
*
* @return the name of the algorithm the MAC implements.
*/
public String getAlgorithmName();
/**
* Return the block size for this MAC (in bytes).
*
* @return the block size for this MAC in bytes.
*/
public int getMacSize();
/**
* add a single byte to the mac for processing.
*
* @param in the byte to be processed.
* @exception IllegalStateException if the MAC is not initialised.
*/
public void update(byte in)
throws IllegalStateException;
/**
* @param in the array containing the input.
* @param inOff the index in the array the data begins at.
* @param len the length of the input starting at inOff.
* @exception IllegalStateException if the MAC is not initialised.
* @exception DataLengthException if there isn't enough data in in.
*/
public void update(byte[] in, int inOff, int len)
throws DataLengthException, IllegalStateException;
/**
* Compute the final stage of the MAC writing the output to the out
* parameter.
* <p>
* doFinal leaves the MAC in the same state it was after the last init.
*
* @param out the array the MAC is to be output to.
* @param outOff the offset into the out buffer the output is to start at.
* @exception DataLengthException if there isn't enough space in out.
* @exception IllegalStateException if the MAC is not initialised.
*/
public int doFinal(byte[] out, int outOff)
throws DataLengthException, IllegalStateException;
/**
* Reset the MAC. At the end of resetting the MAC should be in the
* in the same state it was after the last init (if there was one).
*/
public void reset();
}