1/* crypto/des/cfb_enc.c */ 2/* Copyright (C) 1995-1997 Eric Young (eay@mincom.oz.au) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay@mincom.oz.au). 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@mincom.oz.au). 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@mincom.oz.au)" 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@mincom.oz.au)" 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 */ 67void des_cfb_encrypt(in, out, numbits, length, schedule, ivec, encrypt) 68unsigned char *in; 69unsigned char *out; 70int numbits; 71long length; 72des_key_schedule schedule; 73des_cblock (*ivec); 74int encrypt; 75 { 76 register DES_LONG d0,d1,v0,v1,n=(numbits+7)/8; 77 register DES_LONG mask0,mask1; 78 register unsigned long l=length; 79 register int num=numbits; 80 DES_LONG ti[2]; 81 unsigned char *iv; 82 83 if (num > 64) return; 84 if (num > 32) 85 { 86 mask0=0xffffffffL; 87 if (num == 64) 88 mask1=mask0; 89 else mask1=(1L<<(num-32))-1; 90 } 91 else 92 { 93 if (num == 32) 94 mask0=0xffffffffL; 95 else mask0=(1L<<num)-1; 96 mask1=0x00000000; 97 } 98 99 iv=(unsigned char *)ivec; 100 c2l(iv,v0); 101 c2l(iv,v1); 102 if (encrypt) 103 { 104 while (l >= n) 105 { 106 l-=n; 107 ti[0]=v0; 108 ti[1]=v1; 109 des_encrypt((DES_LONG *)ti,schedule,DES_ENCRYPT); 110 c2ln(in,d0,d1,n); 111 in+=n; 112 d0=(d0^ti[0])&mask0; 113 d1=(d1^ti[1])&mask1; 114 l2cn(d0,d1,out,n); 115 out+=n; 116 /* 30-08-94 - eay - changed because l>>32 and 117 * l<<32 are bad under gcc :-( */ 118 if (num == 32) 119 { v0=v1; v1=d0; } 120 else if (num == 64) 121 { v0=d0; v1=d1; } 122 else if (num > 32) /* && num != 64 */ 123 { 124 v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL; 125 v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL; 126 } 127 else /* num < 32 */ 128 { 129 v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL; 130 v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL; 131 } 132 } 133 } 134 else 135 { 136 while (l >= n) 137 { 138 l-=n; 139 ti[0]=v0; 140 ti[1]=v1; 141 des_encrypt((DES_LONG *)ti,schedule,DES_ENCRYPT); 142 c2ln(in,d0,d1,n); 143 in+=n; 144 /* 30-08-94 - eay - changed because l>>32 and 145 * l<<32 are bad under gcc :-( */ 146 if (num == 32) 147 { v0=v1; v1=d0; } 148 else if (num == 64) 149 { v0=d0; v1=d1; } 150 else if (num > 32) /* && num != 64 */ 151 { 152 v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL; 153 v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL; 154 } 155 else /* num < 32 */ 156 { 157 v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL; 158 v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL; 159 } 160 d0=(d0^ti[0])&mask0; 161 d1=(d1^ti[1])&mask1; 162 l2cn(d0,d1,out,n); 163 out+=n; 164 } 165 } 166 iv=(unsigned char *)ivec; 167 l2c(v0,iv); 168 l2c(v1,iv); 169 v0=v1=d0=d1=ti[0]=ti[1]=0; 170 } 171 172