From 554fd8c5195424bdbcabf5de30fdc183aba391bd Mon Sep 17 00:00:00 2001 From: upstream source tree Date: Sun, 15 Mar 2015 20:14:05 -0400 Subject: obtained gcc-4.6.4.tar.bz2 from upstream website; verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository. --- libjava/classpath/gnu/javax/crypto/mode/CFB.java | 155 +++++++++++++++++++++++ 1 file changed, 155 insertions(+) create mode 100644 libjava/classpath/gnu/javax/crypto/mode/CFB.java (limited to 'libjava/classpath/gnu/javax/crypto/mode/CFB.java') diff --git a/libjava/classpath/gnu/javax/crypto/mode/CFB.java b/libjava/classpath/gnu/javax/crypto/mode/CFB.java new file mode 100644 index 000000000..c5f06e11c --- /dev/null +++ b/libjava/classpath/gnu/javax/crypto/mode/CFB.java @@ -0,0 +1,155 @@ +/* CFB.java -- + Copyright (C) 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.mode; + +import gnu.java.security.Registry; +import gnu.javax.crypto.cipher.IBlockCipher; + +/** + * The cipher feedback mode. CFB mode is a stream mode that operates on s + * bit blocks, where 1 <= s <= b, if b is the + * underlying cipher's block size. Encryption is: + * 
+ *  I[1] = IV
+ *  I[j] = LSB(b-s, I[j-1]) | C[j-1]   for j = 2...n
+ *  O[j] = CIPH(K, I[j])               for j = 1,2...n
+ *  C[j] = P[j] ˆ MSB(s, O[j])         for j = 1,2...n
+ *
+ *

+ * And decryption is: + * 

+ *  I[1] = IV
+ *  I[j] = LSB(b-s, I[j-1]) | C[j-1]   for j = 2...n
+ *  O[j] = CIPH(K, I[j])               for j = 1,2...n
+ *  P[j] = C[j] ˆ MSB(s, O[j])         for j = 1,2...n
+ *
+ *

+ * CFB mode requires an initialization vector, which need not be kept secret. + *

+ * References: + *

    + *
  1. Bruce Schneier, Applied Cryptography: Protocols, Algorithms, and + * Source Code in C, Second Edition. (1996 John Wiley and Sons) ISBN + * 0-471-11709-9.
    2. + *
  2. + * Recommendation for Block Cipher Modes of Operation Methods and Techniques, + * Morris Dworkin.
    3. + *
+ */ +public class CFB + extends BaseMode +{ + /** The shift register, the input block to the block cipher. */ + private byte[] shiftRegister; + /** The output block from the block cipher. */ + private byte[] scratch; + + /** + * Package-private constructor for the factory class. + * + * @param underlyingCipher The cipher implementation. + * @param cipherBlockSize The cipher's block size. + */ + CFB(IBlockCipher underlyingCipher, int cipherBlockSize) + { + super(Registry.CFB_MODE, underlyingCipher, cipherBlockSize); + } + + /** + * Cloneing constructor. + * + * @param that The instance being cloned. + */ + private CFB(CFB that) + { + this((IBlockCipher) that.cipher.clone(), that.cipherBlockSize); + } + + public Object clone() + { + return new CFB(this); + } + + public void setup() + { + if (modeBlockSize > cipherBlockSize) + throw new IllegalArgumentException( + "CFB block size cannot be larger than the cipher block size"); + shiftRegister = new byte[cipherBlockSize]; + scratch = new byte[cipherBlockSize]; + System.arraycopy(iv, 0, + shiftRegister, 0, + Math.min(iv.length, cipherBlockSize)); + } + + public void teardown() + { + if (shiftRegister != null) + for (int i = 0; i < shiftRegister.length; i++) + shiftRegister[i] = 0; + shiftRegister = null; + } + + public void encryptBlock(byte[] in, int inOffset, byte[] out, int outOffset) + { + cipher.encryptBlock(shiftRegister, 0, scratch, 0); + for (int i = 0; i < modeBlockSize; i++) + out[outOffset + i] = (byte)(in[inOffset + i] ^ scratch[i]); + System.arraycopy(shiftRegister, modeBlockSize, + shiftRegister, 0, + cipherBlockSize - modeBlockSize); + System.arraycopy(out, outOffset, + shiftRegister, cipherBlockSize - modeBlockSize, + modeBlockSize); + } + + public void decryptBlock(byte[] in, int inOffset, byte[] out, int outOffset) + { + cipher.encryptBlock(shiftRegister, 0, scratch, 0); + for (int i = 0; i < modeBlockSize; i++) + out[outOffset + i] = (byte)(in[inOffset + i] ^ scratch[i]); + System.arraycopy(shiftRegister, modeBlockSize, + shiftRegister, 0, + cipherBlockSize - modeBlockSize); + System.arraycopy(in, inOffset, + shiftRegister, cipherBlockSize - modeBlockSize, + modeBlockSize); + } +} -- cgit v1.2.3