Files
pj2/lib/edu/rit/crypto/StreamCipher.java
2016-04-27 01:07:35 -04:00

80 lines
2.8 KiB
Java

//******************************************************************************
//
// File: StreamCipher.java
// Package: edu.rit.crypto
// Unit: Interface edu.rit.crypto.StreamCipher
//
// This Java source file is copyright (C) 2013 by Alan Kaminsky. All rights
// reserved. For further information, contact the author, Alan Kaminsky, at
// ark@cs.rit.edu.
//
// This Java source file is part of the Parallel Java 2 Library ("PJ2"). PJ2 is
// free software; you can redistribute it and/or modify it under the terms of
// the GNU General Public License as published by the Free Software Foundation;
// either version 3 of the License, or (at your option) any later version.
//
// PJ2 is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
// A PARTICULAR PURPOSE. See the GNU General Public License for more details.
//
// A copy of the GNU General Public License is provided in the file gpl.txt. You
// may also obtain a copy of the GNU General Public License on the World Wide
// Web at http://www.gnu.org/licenses/gpl.html.
//
//******************************************************************************
package edu.rit.crypto;
/**
* Interface StreamCipher specifies the interface for a stream cipher.
*
* @author Alan Kaminsky
* @version 09-Aug-2013
*/
public interface StreamCipher
{
/**
* Returns this stream cipher's key size in bytes. If the stream cipher
* includes both a key and a nonce, <TT>keySize()</TT> returns the size of
* the key plus the nonce in bytes.
*
* @return Key size.
*/
public int keySize();
/**
* Set the key for this stream cipher. <TT>key</TT> must be an array of
* bytes whose length is equal to <TT>keySize()</TT>. If the stream cipher
* includes both a key and a nonce, <TT>key</TT> contains the bytes of the
* key followed by the bytes of the nonce. The keystream generator is
* initialized, such that successive calls to <TT>encrypt()</TT> will
* encrypt or decrypt a series of bytes.
*
* @param key Key.
*
* @exception NullPointerException
* (unchecked exception) Thrown if <TT>key</TT> is null.
* @exception IndexOutOfBoundsException
* (unchecked exception) Thrown if <TT>key.length</TT> &ne;
* <TT>keySize()</TT>.
*/
public void setKey
(byte[] key);
/**
* Encrypt or decrypt the given byte. Only the least significant 8 bits of
* <TT>b</TT> are used. If <TT>b</TT> is a plaintext byte, the ciphertext
* byte is returned as a value from 0 to 255. If <TT>b</TT> is a ciphertext
* byte, the plaintext byte is returned as a value from 0 to 255.
*
* @param b Plaintext byte (if encrypting), ciphertext byte (if
* decrypting).
*
* @return Ciphertext byte (if encrypting), plaintext byte (if decrypting).
*/
public int encrypt
(int b);
}