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+/* ISO10126.java -- An implementation of the ISO 10126-2 padding scheme
+ Copyright (C) 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 gnu.java.security.Registry;
+import gnu.java.security.util.PRNG;
+
+/**
+ * The implementation of the ISO 10126-2 padding algorithm.
+ * <p>
+ * The last byte of the padding block is the number of padding bytes, all other
+ * padding bytes are random.
+ * <p>
+ * References:
+ * <ol>
+ * <li><a href="http://www.w3.org/TR/xmlenc-core/">XML Encryption Syntax and
+ * Processing</a> Section "5.2 Block Encryption Algorithms"; "Padding".</li>
+ * </ol>
+ */
+public final class ISO10126
+ extends BasePad
+{
+ /** Used to generate random numbers for padding bytes. */
+ private PRNG prng;
+
+ ISO10126()
+ {
+ super(Registry.ISO10126_PAD);
+ prng = PRNG.getInstance();
+ }
+
+ public void setup()
+ {
+ // Nothing to do here
+ }
+
+ public byte[] pad(byte[] in, int offset, int length)
+ {
+ int padLength = blockSize - (length % blockSize);
+ final byte[] pad = new byte[padLength];
+
+ // generate random numbers for the padding bytes except for the last byte
+ prng.nextBytes(pad, 0, padLength - 1);
+ // the last byte contains the number of padding bytes
+ pad[padLength - 1] = (byte) padLength;
+
+ return pad;
+ }
+
+ public int unpad(byte[] in, int offset, int length)
+ throws WrongPaddingException
+ {
+ // the last byte contains the number of padding bytes
+ int padLength = in[offset + length - 1] & 0xFF;
+ if (padLength > length)
+ throw new WrongPaddingException();
+
+ return padLength;
+ }
+
+ /**
+ * The default self-test in the super-class would take too long to finish
+ * with this type of padder --due to the large amount of random data needed.
+ * We override the default test and replace it with a simple one for a 16-byte
+ * block-size (default AES block-size). The Mauve test TestOfISO10126 will
+ * exercise all block-sizes that the default self-test uses for the other
+ * padders.
+ */
+ public boolean selfTest()
+ {
+ return test1BlockSize(16, new byte[1024]);
+ }
+}