155714Skris/* crypto/des/ofb_enc.c */ 255714Skris/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 355714Skris * All rights reserved. 455714Skris * 555714Skris * This package is an SSL implementation written 655714Skris * by Eric Young (eay@cryptsoft.com). 755714Skris * The implementation was written so as to conform with Netscapes SSL. 8280297Sjkim * 955714Skris * This library is free for commercial and non-commercial use as long as 1055714Skris * the following conditions are aheared to. The following conditions 1155714Skris * apply to all code found in this distribution, be it the RC4, RSA, 1255714Skris * lhash, DES, etc., code; not just the SSL code. The SSL documentation 1355714Skris * included with this distribution is covered by the same copyright terms 1455714Skris * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15280297Sjkim * 1655714Skris * Copyright remains Eric Young's, and as such any Copyright notices in 1755714Skris * the code are not to be removed. 1855714Skris * If this package is used in a product, Eric Young should be given attribution 1955714Skris * as the author of the parts of the library used. 2055714Skris * This can be in the form of a textual message at program startup or 2155714Skris * in documentation (online or textual) provided with the package. 22280297Sjkim * 2355714Skris * Redistribution and use in source and binary forms, with or without 2455714Skris * modification, are permitted provided that the following conditions 2555714Skris * are met: 2655714Skris * 1. Redistributions of source code must retain the copyright 2755714Skris * notice, this list of conditions and the following disclaimer. 2855714Skris * 2. Redistributions in binary form must reproduce the above copyright 2955714Skris * notice, this list of conditions and the following disclaimer in the 3055714Skris * documentation and/or other materials provided with the distribution. 3155714Skris * 3. All advertising materials mentioning features or use of this software 3255714Skris * must display the following acknowledgement: 3355714Skris * "This product includes cryptographic software written by 3455714Skris * Eric Young (eay@cryptsoft.com)" 3555714Skris * The word 'cryptographic' can be left out if the rouines from the library 3655714Skris * being used are not cryptographic related :-). 37280297Sjkim * 4. If you include any Windows specific code (or a derivative thereof) from 3855714Skris * the apps directory (application code) you must include an acknowledgement: 3955714Skris * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40280297Sjkim * 4155714Skris * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 4255714Skris * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 4355714Skris * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 4455714Skris * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 4555714Skris * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 4655714Skris * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 4755714Skris * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 4855714Skris * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 4955714Skris * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 5055714Skris * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 5155714Skris * SUCH DAMAGE. 52280297Sjkim * 5355714Skris * The licence and distribution terms for any publically available version or 5455714Skris * derivative of this code cannot be changed. i.e. this code cannot simply be 5555714Skris * copied and put under another distribution licence 5655714Skris * [including the GNU Public Licence.] 5755714Skris */ 5855714Skris 5955714Skris#include "des_locl.h" 6055714Skris 61280297Sjkim/* 62280297Sjkim * The input and output are loaded in multiples of 8 bits. What this means is 63280297Sjkim * that if you hame numbits=12 and length=2 the first 12 bits will be 64280297Sjkim * retrieved from the first byte and half the second. The second 12 bits 65280297Sjkim * will come from the 3rd and half the 4th byte. 6655714Skris */ 67109998Smarkmvoid DES_ofb_encrypt(const unsigned char *in, unsigned char *out, int numbits, 68280297Sjkim long length, DES_key_schedule *schedule, 69280297Sjkim DES_cblock *ivec) 70280297Sjkim{ 71280297Sjkim register DES_LONG d0, d1, vv0, vv1, v0, v1, n = (numbits + 7) / 8; 72280297Sjkim register DES_LONG mask0, mask1; 73280297Sjkim register long l = length; 74280297Sjkim register int num = numbits; 75280297Sjkim DES_LONG ti[2]; 76280297Sjkim unsigned char *iv; 7755714Skris 78280297Sjkim if (num > 64) 79280297Sjkim return; 80280297Sjkim if (num > 32) { 81280297Sjkim mask0 = 0xffffffffL; 82280297Sjkim if (num >= 64) 83280297Sjkim mask1 = mask0; 84280297Sjkim else 85280297Sjkim mask1 = (1L << (num - 32)) - 1; 86280297Sjkim } else { 87280297Sjkim if (num == 32) 88280297Sjkim mask0 = 0xffffffffL; 89280297Sjkim else 90280297Sjkim mask0 = (1L << num) - 1; 91280297Sjkim mask1 = 0x00000000L; 92280297Sjkim } 9355714Skris 94280297Sjkim iv = &(*ivec)[0]; 95280297Sjkim c2l(iv, v0); 96280297Sjkim c2l(iv, v1); 97280297Sjkim ti[0] = v0; 98280297Sjkim ti[1] = v1; 99280297Sjkim while (l-- > 0) { 100280297Sjkim ti[0] = v0; 101280297Sjkim ti[1] = v1; 102280297Sjkim DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT); 103280297Sjkim vv0 = ti[0]; 104280297Sjkim vv1 = ti[1]; 105280297Sjkim c2ln(in, d0, d1, n); 106280297Sjkim in += n; 107280297Sjkim d0 = (d0 ^ vv0) & mask0; 108280297Sjkim d1 = (d1 ^ vv1) & mask1; 109280297Sjkim l2cn(d0, d1, out, n); 110280297Sjkim out += n; 11155714Skris 112280297Sjkim if (num == 32) { 113280297Sjkim v0 = v1; 114280297Sjkim v1 = vv0; 115280297Sjkim } else if (num == 64) { 116280297Sjkim v0 = vv0; 117280297Sjkim v1 = vv1; 118280297Sjkim } else if (num > 32) { /* && num != 64 */ 119280297Sjkim v0 = ((v1 >> (num - 32)) | (vv0 << (64 - num))) & 0xffffffffL; 120280297Sjkim v1 = ((vv0 >> (num - 32)) | (vv1 << (64 - num))) & 0xffffffffL; 121280297Sjkim } else { /* num < 32 */ 12255714Skris 123280297Sjkim v0 = ((v0 >> num) | (v1 << (32 - num))) & 0xffffffffL; 124280297Sjkim v1 = ((v1 >> num) | (vv0 << (32 - num))) & 0xffffffffL; 125280297Sjkim } 126280297Sjkim } 127280297Sjkim iv = &(*ivec)[0]; 128280297Sjkim l2c(v0, iv); 129280297Sjkim l2c(v1, iv); 130280297Sjkim v0 = v1 = d0 = d1 = ti[0] = ti[1] = vv0 = vv1 = 0; 131280297Sjkim} 132