mirror of git://gcc.gnu.org/git/gcc.git
110 lines
3.7 KiB
Java
110 lines
3.7 KiB
Java
/* ISO10126.java -- An implementation of the ISO 10126-2 padding scheme
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Copyright (C) 2006 Free Software Foundation, Inc.
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This file is a part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or (at
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your option) any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
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USA
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package gnu.javax.crypto.pad;
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import gnu.java.security.Registry;
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import gnu.java.security.util.PRNG;
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/**
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* The implementation of the ISO 10126-2 padding algorithm.
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* <p>
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* The last byte of the padding block is the number of padding bytes, all other
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* padding bytes are random.
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* <p>
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* References:
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* <ol>
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* <li><a href="http://www.w3.org/TR/xmlenc-core/">XML Encryption Syntax and
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* Processing</a> Section "5.2 Block Encryption Algorithms"; "Padding".</li>
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* </ol>
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*/
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public final class ISO10126
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extends BasePad
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{
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/** Used to generate random numbers for padding bytes. */
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private PRNG prng;
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ISO10126()
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{
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super(Registry.ISO10126_PAD);
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prng = PRNG.getInstance();
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}
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public void setup()
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{
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// Nothing to do here
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}
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public byte[] pad(byte[] in, int offset, int length)
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{
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int padLength = blockSize - (length % blockSize);
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final byte[] pad = new byte[padLength];
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// generate random numbers for the padding bytes except for the last byte
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prng.nextBytes(pad, 0, padLength - 1);
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// the last byte contains the number of padding bytes
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pad[padLength - 1] = (byte) padLength;
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return pad;
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}
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public int unpad(byte[] in, int offset, int length)
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throws WrongPaddingException
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{
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// the last byte contains the number of padding bytes
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int padLength = in[offset + length - 1] & 0xFF;
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if (padLength > length)
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throw new WrongPaddingException();
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return padLength;
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}
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/**
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* The default self-test in the super-class would take too long to finish
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* with this type of padder --due to the large amount of random data needed.
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* We override the default test and replace it with a simple one for a 16-byte
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* block-size (default AES block-size). The Mauve test TestOfISO10126 will
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* exercise all block-sizes that the default self-test uses for the other
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* padders.
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*/
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public boolean selfTest()
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{
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return test1BlockSize(16, new byte[1024]);
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}
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}
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