| /* IPad.java -- |
| Copyright (C) 2001, 2002, 2006 Free Software Foundation, Inc. |
| |
| This file is a part of GNU Classpath. |
| |
| GNU Classpath 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 2 of the License, or (at |
| your option) any later version. |
| |
| GNU Classpath 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. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| USA |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.javax.crypto.pad; |
| |
| import java.util.Map; |
| |
| /** |
| * The basic visible methods, and attribute names, of every padding algorithm. |
| * <p> |
| * Padding algorithms serve to <i>pad</i> and <i>unpad</i> byte arrays usually |
| * as the last step in an <i>encryption</i> or respectively a <i>decryption</i> |
| * operation. Their input buffers are usually those processed by instances of |
| * {@link gnu.javax.crypto.mode.IMode} and/or |
| * {@link gnu.javax.crypto.cipher.IBlockCipher}. |
| */ |
| public interface IPad |
| { |
| /** |
| * Property name of the block size in which to operate the padding algorithm. |
| * The value associated with this property name is taken to be a positive |
| * {@link Integer} greater than zero. |
| */ |
| String PADDING_BLOCK_SIZE = "gnu.crypto.pad.block.size"; |
| |
| /** @return the canonical name of this instance. */ |
| String name(); |
| |
| /** |
| * Initialises the padding scheme with a designated block size. |
| * |
| * @param bs the designated block size. |
| * @exception IllegalStateException if the instance is already initialised. |
| * @exception IllegalArgumentException if the block size value is invalid. |
| */ |
| void init(int bs) throws IllegalStateException; |
| |
| /** |
| * Initialises the algorithm with designated attributes. Names, valid and/or |
| * recognisable by all concrete implementations are described in the class |
| * documentation above. Other algorithm-specific attributes MUST be documented |
| * in the implementation class of that padding algorithm. |
| * |
| * @param attributes a set of name-value pairs that describes the desired |
| * future behaviour of this instance. |
| * @exception IllegalStateException if the instance is already initialised. |
| * @exception IllegalArgumentException if the block size value is invalid. |
| */ |
| void init(Map attributes) throws IllegalStateException; |
| |
| /** |
| * Returns the byte sequence that should be appended to the designated input. |
| * |
| * @param in the input buffer containing the bytes to pad. |
| * @param offset the starting index of meaningful data in <i>in</i>. |
| * @param length the number of meaningful bytes in <i>in</i>. |
| * @return the possibly 0-byte long sequence to be appended to the designated |
| * input. |
| */ |
| byte[] pad(byte[] in, int offset, int length); |
| |
| /** |
| * Returns the number of bytes to discard from a designated input buffer. |
| * |
| * @param in the input buffer containing the bytes to unpad. |
| * @param offset the starting index of meaningful data in <i>in</i>. |
| * @param length the number of meaningful bytes in <i>in</i>. |
| * @return the number of bytes to discard, to the left of index position |
| * <code>offset + length</code> in <i>in</i>. In other words, if |
| * the return value of a successful invocation of this method is |
| * <code>result</code>, then the unpadded byte sequence will be |
| * <code>offset + length - result</code> bytes in <i>in</i>, |
| * starting from index position <code>offset</code>. |
| * @exception WrongPaddingException if the data is not terminated with the |
| * expected padding bytes. |
| */ |
| int unpad(byte[] in, int offset, int length) throws WrongPaddingException; |
| |
| /** |
| * Resets the scheme instance for re-initialisation and use with other |
| * characteristics. This method always succeeds. |
| */ |
| void reset(); |
| |
| /** |
| * A basic symmetric pad/unpad test. |
| * |
| * @return <code>true</code> if the implementation passes a basic symmetric |
| * self-test. Returns <code>false</code> otherwise. |
| */ |
| boolean selfTest(); |
| } |