1 /* crypto/aes/aes_ofb.c -*- mode:C; c-file-style: "eay" -*- */ 2 /* ==================================================================== 3 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in 14 * the documentation and/or other materials provided with the 15 * distribution. 16 * 17 * 3. All advertising materials mentioning features or use of this 18 * software must display the following acknowledgment: 19 * "This product includes software developed by the OpenSSL Project 20 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 21 * 22 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 23 * endorse or promote products derived from this software without 24 * prior written permission. For written permission, please contact 25 * openssl-core@openssl.org. 26 * 27 * 5. Products derived from this software may not be called "OpenSSL" 28 * nor may "OpenSSL" appear in their names without prior written 29 * permission of the OpenSSL Project. 30 * 31 * 6. Redistributions of any form whatsoever must retain the following 32 * acknowledgment: 33 * "This product includes software developed by the OpenSSL Project 34 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 35 * 36 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 37 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 39 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 40 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 41 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 42 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 43 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 44 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 45 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 46 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 47 * OF THE POSSIBILITY OF SUCH DAMAGE. 48 * ==================================================================== 49 * 50 */ 51 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 52 * All rights reserved. 53 * 54 * This package is an SSL implementation written 55 * by Eric Young (eay@cryptsoft.com). 56 * The implementation was written so as to conform with Netscapes SSL. 57 * 58 * This library is free for commercial and non-commercial use as long as 59 * the following conditions are aheared to. The following conditions 60 * apply to all code found in this distribution, be it the RC4, RSA, 61 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 62 * included with this distribution is covered by the same copyright terms 63 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 64 * 65 * Copyright remains Eric Young's, and as such any Copyright notices in 66 * the code are not to be removed. 67 * If this package is used in a product, Eric Young should be given attribution 68 * as the author of the parts of the library used. 69 * This can be in the form of a textual message at program startup or 70 * in documentation (online or textual) provided with the package. 71 * 72 * Redistribution and use in source and binary forms, with or without 73 * modification, are permitted provided that the following conditions 74 * are met: 75 * 1. Redistributions of source code must retain the copyright 76 * notice, this list of conditions and the following disclaimer. 77 * 2. Redistributions in binary form must reproduce the above copyright 78 * notice, this list of conditions and the following disclaimer in the 79 * documentation and/or other materials provided with the distribution. 80 * 3. All advertising materials mentioning features or use of this software 81 * must display the following acknowledgement: 82 * "This product includes cryptographic software written by 83 * Eric Young (eay@cryptsoft.com)" 84 * The word 'cryptographic' can be left out if the rouines from the library 85 * being used are not cryptographic related :-). 86 * 4. If you include any Windows specific code (or a derivative thereof) from 87 * the apps directory (application code) you must include an acknowledgement: 88 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 89 * 90 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 91 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 92 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 93 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 94 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 95 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 96 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 97 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 98 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 99 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 100 * SUCH DAMAGE. 101 * 102 * The licence and distribution terms for any publically available version or 103 * derivative of this code cannot be changed. i.e. this code cannot simply be 104 * copied and put under another distribution licence 105 * [including the GNU Public Licence.] 106 */ 107 108 #ifndef AES_DEBUG 109 # ifndef NDEBUG 110 # define NDEBUG 111 # endif 112 #endif 113 #include <assert.h> 114 115 #include <openssl/aes.h> 116 #include "aes_locl.h" 117 118 /* The input and output encrypted as though 128bit ofb mode is being 119 * used. The extra state information to record how much of the 120 * 128bit block we have used is contained in *num; 121 */ 122 void AES_ofb128_encrypt(const unsigned char *in, unsigned char *out, 123 const unsigned long length, const AES_KEY *key, 124 unsigned char *ivec, int *num) { 125 126 unsigned int n; 127 unsigned long l=length; 128 129 assert(in && out && key && ivec && num); 130 131 n = *num; 132 133 while (l--) { 134 if (n == 0) { 135 AES_encrypt(ivec, ivec, key); 136 } 137 *(out++) = *(in++) ^ ivec[n]; 138 n = (n+1) % AES_BLOCK_SIZE; 139 } 140 141 *num=n; 142 } 143