cfb_enc.c revision 120631
1/* crypto/des/cfb_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/* The input and output are loaded in multiples of 8 bits. 62 * What this means is that if you hame numbits=12 and length=2 63 * the first 12 bits will be retrieved from the first byte and half 64 * the second. The second 12 bits will come from the 3rd and half the 4th 65 * byte. 66 */ 67/* WARNING WARNING: this uses in and out in 8-byte chunks regardless of 68 * length */ 69/* Until Aug 1 2003 this function did not correctly implement CFB-r, so it 70 * will not be compatible with any encryption prior to that date. Ben. */ 71void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits, 72 long length, DES_key_schedule *schedule, DES_cblock *ivec, 73 int enc) 74 { 75 register DES_LONG d0,d1,v0,v1,n=(numbits+7)/8; 76 register unsigned long l=length; 77 register int num=numbits; 78 DES_LONG ti[2]; 79 unsigned char *iv; 80 unsigned char ovec[16]; 81 82 if (num > 64) return; 83 iv = &(*ivec)[0]; 84 c2l(iv,v0); 85 c2l(iv,v1); 86 if (enc) 87 { 88 while (l >= n) 89 { 90 l-=n; 91 ti[0]=v0; 92 ti[1]=v1; 93 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); 94 c2ln(in,d0,d1,n); 95 in+=n; 96 d0^=ti[0]; 97 d1^=ti[1]; 98 l2cn(d0,d1,out,n); 99 out+=n; 100 /* 30-08-94 - eay - changed because l>>32 and 101 * l<<32 are bad under gcc :-( */ 102 if (num == 32) 103 { v0=v1; v1=d0; } 104 else if (num == 64) 105 { v0=d0; v1=d1; } 106 else 107 { 108 iv=&ovec[0]; 109 l2c(v0,iv); 110 l2c(v1,iv); 111 l2c(d0,iv); 112 l2c(d1,iv); 113 /* shift ovec left most of the bits... */ 114 memmove(ovec,ovec+num/8,8+(num%8 ? 1 : 0)); 115 /* now the remaining bits */ 116 if(num%8 != 0) 117 for(n=0 ; n < 8 ; ++n) 118 { 119 ovec[n]<<=num%8; 120 ovec[n]|=ovec[n+1]>>(8-num%8); 121 } 122 iv=&ovec[0]; 123 c2l(iv,v0); 124 c2l(iv,v1); 125 } 126 } 127 } 128 else 129 { 130 while (l >= n) 131 { 132 l-=n; 133 ti[0]=v0; 134 ti[1]=v1; 135 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); 136 c2ln(in,d0,d1,n); 137 in+=n; 138 /* 30-08-94 - eay - changed because l>>32 and 139 * l<<32 are bad under gcc :-( */ 140 if (num == 32) 141 { v0=v1; v1=d0; } 142 else if (num == 64) 143 { v0=d0; v1=d1; } 144 else 145 { 146 iv=&ovec[0]; 147 l2c(v0,iv); 148 l2c(v1,iv); 149 l2c(d0,iv); 150 l2c(d1,iv); 151 /* shift ovec left most of the bits... */ 152 memmove(ovec,ovec+num/8,8+(num%8 ? 1 : 0)); 153 /* now the remaining bits */ 154 if(num%8 != 0) 155 for(n=0 ; n < 8 ; ++n) 156 { 157 ovec[n]<<=num%8; 158 ovec[n]|=ovec[n+1]>>(8-num%8); 159 } 160 iv=&ovec[0]; 161 c2l(iv,v0); 162 c2l(iv,v1); 163 } 164 d0^=ti[0]; 165 d1^=ti[1]; 166 l2cn(d0,d1,out,n); 167 out+=n; 168 } 169 } 170 iv = &(*ivec)[0]; 171 l2c(v0,iv); 172 l2c(v1,iv); 173 v0=v1=d0=d1=ti[0]=ti[1]=0; 174 } 175 176