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Diffstat (limited to 'libjava/classpath/gnu/javax/crypto/pad/PKCS7.java')
-rw-r--r-- | libjava/classpath/gnu/javax/crypto/pad/PKCS7.java | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/crypto/pad/PKCS7.java b/libjava/classpath/gnu/javax/crypto/pad/PKCS7.java new file mode 100644 index 000000000..9dd67fc81 --- /dev/null +++ b/libjava/classpath/gnu/javax/crypto/pad/PKCS7.java @@ -0,0 +1,111 @@ +/* PKCS7.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 gnu.java.security.Configuration; +import gnu.java.security.Registry; +import gnu.java.security.util.Util; + +import java.util.logging.Logger; + +/** + * The implementation of the PKCS7 padding algorithm. + * <p> + * This algorithm is described for 8-byte blocks in [RFC-1423] and extended to + * block sizes of up to 256 bytes in [PKCS-7]. + * <p> + * References: + * <ol> + * <li><a href="http://www.ietf.org/rfc/rfc1423.txt">RFC-1423</a>: Privacy + * Enhancement for Internet Electronic Mail: Part III: Algorithms, Modes, and + * Identifiers.</li> + * <li><a href="http://www.ietf.org/">IETF</a>.</li> + * <li><a href="http://www.rsasecurity.com/rsalabs/pkcs/pkcs-7/">[PKCS-7]</a> + * PKCS #7: Cryptographic Message Syntax Standard - An RSA Laboratories + * Technical Note.</li> + * <li><a href="http://www.rsasecurity.com/">RSA Security</a>.</li> + * </ol> + */ +public final class PKCS7 + extends BasePad +{ + private static final Logger log = Logger.getLogger(PKCS7.class.getName()); + + /** + * Trivial package-private constructor for use by the <i>Factory</i> class. + * + * @see PadFactory + */ + PKCS7() + { + super(Registry.PKCS7_PAD); + } + + public void setup() + { + if (blockSize < 2 || blockSize > 256) + throw new IllegalArgumentException(); + } + + public byte[] pad(byte[] in, int offset, int length) + { + int padLength = blockSize; + if (length % blockSize != 0) + padLength = blockSize - length % blockSize; + byte[] result = new byte[padLength]; + for (int i = 0; i < padLength;) + result[i++] = (byte) padLength; + if (Configuration.DEBUG) + log.fine("padding: 0x" + Util.toString(result)); + return result; + } + + public int unpad(byte[] in, int offset, int length) + throws WrongPaddingException + { + int limit = offset + length; + int result = in[--limit] & 0xFF; + for (int i = 0; i < result - 1; i++) + if (result != (in[--limit] & 0xFF)) + throw new WrongPaddingException(); + if (Configuration.DEBUG) + log.fine("padding length: " + result); + return result; + } +} |