1 /* $OpenBSD: cfb_enc.c,v 1.14 2021/11/09 18:40:21 bcook Exp $ */ 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 #include <endian.h> 61 62 /* The input and output are loaded in multiples of 8 bits. 63 * What this means is that if you hame numbits=12 and length=2 64 * the first 12 bits will be retrieved from the first byte and half 65 * the second. The second 12 bits will come from the 3rd and half the 4th 66 * byte. 67 */ 68 /* Until Aug 1 2003 this function did not correctly implement CFB-r, so it 69 * will not be compatible with any encryption prior to that date. Ben. */ 70 void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits, 71 long length, DES_key_schedule *schedule, DES_cblock *ivec, 72 int enc) 73 { 74 DES_LONG d0,d1,v0,v1; 75 unsigned long l=length; 76 int num=numbits/8,n=(numbits+7)/8,i,rem=numbits%8; 77 DES_LONG ti[2]; 78 unsigned char *iv; 79 #if BYTE_ORDER != LITTLE_ENDIAN 80 unsigned char ovec[16]; 81 #else 82 unsigned int sh[4]; 83 unsigned char *ovec=(unsigned char *)sh; 84 #endif 85 86 if (numbits<=0 || numbits > 64) return; 87 iv = &(*ivec)[0]; 88 c2l(iv,v0); 89 c2l(iv,v1); 90 if (enc) 91 { 92 while (l >= (unsigned long)n) 93 { 94 l-=n; 95 ti[0]=v0; 96 ti[1]=v1; 97 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); 98 c2ln(in,d0,d1,n); 99 in+=n; 100 d0^=ti[0]; 101 d1^=ti[1]; 102 l2cn(d0,d1,out,n); 103 out+=n; 104 /* 30-08-94 - eay - changed because l>>32 and 105 * l<<32 are bad under gcc :-( */ 106 if (numbits == 32) 107 { v0=v1; v1=d0; } 108 else if (numbits == 64) 109 { v0=d0; v1=d1; } 110 else 111 { 112 #if BYTE_ORDER != LITTLE_ENDIAN 113 iv=&ovec[0]; 114 l2c(v0,iv); 115 l2c(v1,iv); 116 l2c(d0,iv); 117 l2c(d1,iv); 118 #else 119 sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1; 120 #endif 121 if (rem==0) 122 memmove(ovec,ovec+num,8); 123 else 124 for(i=0 ; i < 8 ; ++i) 125 ovec[i]=ovec[i+num]<<rem | 126 ovec[i+num+1]>>(8-rem); 127 #if BYTE_ORDER == LITTLE_ENDIAN 128 v0=sh[0], v1=sh[1]; 129 #else 130 iv=&ovec[0]; 131 c2l(iv,v0); 132 c2l(iv,v1); 133 #endif 134 } 135 } 136 } 137 else 138 { 139 while (l >= (unsigned long)n) 140 { 141 l-=n; 142 ti[0]=v0; 143 ti[1]=v1; 144 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); 145 c2ln(in,d0,d1,n); 146 in+=n; 147 /* 30-08-94 - eay - changed because l>>32 and 148 * l<<32 are bad under gcc :-( */ 149 if (numbits == 32) 150 { v0=v1; v1=d0; } 151 else if (numbits == 64) 152 { v0=d0; v1=d1; } 153 else 154 { 155 #if BYTE_ORDER != LITTLE_ENDIAN 156 iv=&ovec[0]; 157 l2c(v0,iv); 158 l2c(v1,iv); 159 l2c(d0,iv); 160 l2c(d1,iv); 161 #else 162 sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1; 163 #endif 164 if (rem==0) 165 memmove(ovec,ovec+num,8); 166 else 167 for(i=0 ; i < 8 ; ++i) 168 ovec[i]=ovec[i+num]<<rem | 169 ovec[i+num+1]>>(8-rem); 170 #if BYTE_ORDER == LITTLE_ENDIAN 171 v0=sh[0], v1=sh[1]; 172 #else 173 iv=&ovec[0]; 174 c2l(iv,v0); 175 c2l(iv,v1); 176 #endif 177 } 178 d0^=ti[0]; 179 d1^=ti[1]; 180 l2cn(d0,d1,out,n); 181 out+=n; 182 } 183 } 184 iv = &(*ivec)[0]; 185 l2c(v0,iv); 186 l2c(v1,iv); 187 v0=v1=d0=d1=ti[0]=ti[1]=0; 188 } 189 190