1/* crypto/des/ofb_enc.c */ 2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay@cryptsoft.com). 7 * The implementation was written so as to conform with Netscapes SSL. 8 * 9 * This library is free for commercial and non-commercial use as long as 10 * the following conditions are aheared to. The following conditions 11 * apply to all code found in this distribution, be it the RC4, RSA, 12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 13 * included with this distribution is covered by the same copyright terms 14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15 * 16 * Copyright remains Eric Young's, and as such any Copyright notices in 17 * the code are not to be removed. 18 * If this package is used in a product, Eric Young should be given attribution 19 * as the author of the parts of the library used. 20 * This can be in the form of a textual message at program startup or 21 * in documentation (online or textual) provided with the package. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 3. All advertising materials mentioning features or use of this software 32 * must display the following acknowledgement: 33 * "This product includes cryptographic software written by 34 * Eric Young (eay@cryptsoft.com)" 35 * The word 'cryptographic' can be left out if the rouines from the library 36 * being used are not cryptographic related :-). 37 * 4. If you include any Windows specific code (or a derivative thereof) from 38 * the apps directory (application code) you must include an acknowledgement: 39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40 * 41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 51 * SUCH DAMAGE. 52 * 53 * The licence and distribution terms for any publically available version or 54 * derivative of this code cannot be changed. i.e. this code cannot simply be 55 * copied and put under another distribution licence 56 * [including the GNU Public Licence.] 57 */ 58 59#include "des_locl.h" 60 61/* 62 * The input and output are loaded in multiples of 8 bits. What this means is 63 * that if you hame numbits=12 and length=2 the first 12 bits will be 64 * retrieved from the first byte and half the second. The second 12 bits 65 * will come from the 3rd and half the 4th byte. 66 */ 67void DES_ofb_encrypt(const unsigned char *in, unsigned char *out, int numbits, 68 long length, DES_key_schedule *schedule, 69 DES_cblock *ivec) 70{ 71 register DES_LONG d0, d1, vv0, vv1, v0, v1, n = (numbits + 7) / 8; 72 register DES_LONG mask0, mask1; 73 register long l = length; 74 register int num = numbits; 75 DES_LONG ti[2]; 76 unsigned char *iv; 77 78 if (num > 64) 79 return; 80 if (num > 32) { 81 mask0 = 0xffffffffL; 82 if (num >= 64) 83 mask1 = mask0; 84 else 85 mask1 = (1L << (num - 32)) - 1; 86 } else { 87 if (num == 32) 88 mask0 = 0xffffffffL; 89 else 90 mask0 = (1L << num) - 1; 91 mask1 = 0x00000000L; 92 } 93 94 iv = &(*ivec)[0]; 95 c2l(iv, v0); 96 c2l(iv, v1); 97 ti[0] = v0; 98 ti[1] = v1; 99 while (l-- > 0) { 100 ti[0] = v0; 101 ti[1] = v1; 102 DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT); 103 vv0 = ti[0]; 104 vv1 = ti[1]; 105 c2ln(in, d0, d1, n); 106 in += n; 107 d0 = (d0 ^ vv0) & mask0; 108 d1 = (d1 ^ vv1) & mask1; 109 l2cn(d0, d1, out, n); 110 out += n; 111 112 if (num == 32) { 113 v0 = v1; 114 v1 = vv0; 115 } else if (num == 64) { 116 v0 = vv0; 117 v1 = vv1; 118 } else if (num > 32) { /* && num != 64 */ 119 v0 = ((v1 >> (num - 32)) | (vv0 << (64 - num))) & 0xffffffffL; 120 v1 = ((vv0 >> (num - 32)) | (vv1 << (64 - num))) & 0xffffffffL; 121 } else { /* num < 32 */ 122 123 v0 = ((v0 >> num) | (v1 << (32 - num))) & 0xffffffffL; 124 v1 = ((v1 >> num) | (vv0 << (32 - num))) & 0xffffffffL; 125 } 126 } 127 iv = &(*ivec)[0]; 128 l2c(v0, iv); 129 l2c(v1, iv); 130 v0 = v1 = d0 = d1 = ti[0] = ti[1] = vv0 = vv1 = 0; 131} 132