1 /* crypto/des/cfb_enc.c */ 2 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay (at) 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 (at) 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 (at) 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 (at) 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 void des_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits, 68 long length, des_key_schedule schedule, des_cblock *ivec, int enc) 69 { 70 register DES_LONG d0,d1,v0,v1,n=(numbits+7)/8; 71 register DES_LONG mask0,mask1; 72 register unsigned long l=length; 73 register int num=numbits; 74 DES_LONG ti[2]; 75 unsigned char *iv; 76 77 if (num > 64) return; 78 if (num > 32) 79 { 80 mask0=0xffffffffL; 81 if (num == 64) 82 mask1=mask0; 83 else mask1=(1L<<(num-32))-1; 84 } 85 else 86 { 87 if (num == 32) 88 mask0=0xffffffffL; 89 else mask0=(1L<<num)-1; 90 mask1=0x00000000L; 91 } 92 93 iv = &(*ivec)[0]; 94 c2l(iv,v0); 95 c2l(iv,v1); 96 if (enc) 97 { 98 while (l >= n) 99 { 100 l-=n; 101 ti[0]=v0; 102 ti[1]=v1; 103 des_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); 104 c2ln(in,d0,d1,n); 105 in+=n; 106 d0=(d0^ti[0])&mask0; 107 d1=(d1^ti[1])&mask1; 108 l2cn(d0,d1,out,n); 109 out+=n; 110 /* 30-08-94 - eay - changed because l>>32 and 111 * l<<32 are bad under gcc :-( */ 112 if (num == 32) 113 { v0=v1; v1=d0; } 114 else if (num == 64) 115 { v0=d0; v1=d1; } 116 else if (num > 32) /* && num != 64 */ 117 { 118 v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL; 119 v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL; 120 } 121 else /* num < 32 */ 122 { 123 v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL; 124 v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL; 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 if (num > 32) /* && num != 64 */ 145 { 146 v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL; 147 v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL; 148 } 149 else /* num < 32 */ 150 { 151 v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL; 152 v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL; 153 } 154 d0=(d0^ti[0])&mask0; 155 d1=(d1^ti[1])&mask1; 156 l2cn(d0,d1,out,n); 157 out+=n; 158 } 159 } 160 iv = &(*ivec)[0]; 161 l2c(v0,iv); 162 l2c(v1,iv); 163 v0=v1=d0=d1=ti[0]=ti[1]=0; 164 } 165 166
Indexes created Mon Mar 02 05:31:46 UTC 2026