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 "e_os.h" 60#include "des_locl.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. */ 70void 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 register DES_LONG d0,d1,v0,v1; 75 register unsigned long l=length,n=(numbits+7)/8; 76 register int num=numbits,i; 77 DES_LONG ti[2]; 78 unsigned char *iv; 79 unsigned char ovec[16]; 80 81 if (num > 64) return; 82 iv = &(*ivec)[0]; 83 c2l(iv,v0); 84 c2l(iv,v1); 85 if (enc) 86 { 87 while (l >= n) 88 { 89 l-=n; 90 ti[0]=v0; 91 ti[1]=v1; 92 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); 93 c2ln(in,d0,d1,n); 94 in+=n; 95 d0^=ti[0]; 96 d1^=ti[1]; 97 l2cn(d0,d1,out,n); 98 out+=n; 99 /* 30-08-94 - eay - changed because l>>32 and 100 * l<<32 are bad under gcc :-( */ 101 if (num == 32) 102 { v0=v1; v1=d0; } 103 else if (num == 64) 104 { v0=d0; v1=d1; } 105 else 106 { 107 iv=&ovec[0]; 108 l2c(v0,iv); 109 l2c(v1,iv); 110 l2c(d0,iv); 111 l2c(d1,iv); 112 /* shift ovec left most of the bits... */ 113 memmove(ovec,ovec+num/8,8+(num%8 ? 1 : 0)); 114 /* now the remaining bits */ 115 if(num%8 != 0) 116 for(i=0 ; i < 8 ; ++i) 117 { 118 ovec[i]<<=num%8; 119 ovec[i]|=ovec[i+1]>>(8-num%8); 120 } 121 iv=&ovec[0]; 122 c2l(iv,v0); 123 c2l(iv,v1); 124 } 125 } 126 } 127 else 128 { 129 while (l >= n) 130 { 131 l-=n; 132 ti[0]=v0; 133 ti[1]=v1; 134 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); 135 c2ln(in,d0,d1,n); 136 in+=n; 137 /* 30-08-94 - eay - changed because l>>32 and 138 * l<<32 are bad under gcc :-( */ 139 if (num == 32) 140 { v0=v1; v1=d0; } 141 else if (num == 64) 142 { v0=d0; v1=d1; } 143 else 144 { 145 iv=&ovec[0]; 146 l2c(v0,iv); 147 l2c(v1,iv); 148 l2c(d0,iv); 149 l2c(d1,iv); 150 /* shift ovec left most of the bits... */ 151 memmove(ovec,ovec+num/8,8+(num%8 ? 1 : 0)); 152 /* now the remaining bits */ 153 if(num%8 != 0) 154 for(i=0 ; i < 8 ; ++i) 155 { 156 ovec[i]<<=num%8; 157 ovec[i]|=ovec[i+1]>>(8-num%8); 158 } 159 iv=&ovec[0]; 160 c2l(iv,v0); 161 c2l(iv,v1); 162 } 163 d0^=ti[0]; 164 d1^=ti[1]; 165 l2cn(d0,d1,out,n); 166 out+=n; 167 } 168 } 169 iv = &(*ivec)[0]; 170 l2c(v0,iv); 171 l2c(v1,iv); 172 v0=v1=d0=d1=ti[0]=ti[1]=0; 173 } 174 175