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Diffstat (limited to 'libjava/classpath/gnu/javax/crypto/pad/ISO10126.java')
-rw-r--r-- | libjava/classpath/gnu/javax/crypto/pad/ISO10126.java | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/crypto/pad/ISO10126.java b/libjava/classpath/gnu/javax/crypto/pad/ISO10126.java new file mode 100644 index 000000000..8e8c59254 --- /dev/null +++ b/libjava/classpath/gnu/javax/crypto/pad/ISO10126.java @@ -0,0 +1,109 @@ +/* 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]); + } +} |