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 "e_os.h" 60 #include "des_locl.h" 61 #include <assert.h> 62 63 /* The input and output are loaded in multiples of 8 bits. 64 * What this means is that if you hame numbits=12 and length=2 65 * the first 12 bits will be retrieved from the first byte and half 66 * the second. The second 12 bits will come from the 3rd and half the 4th 67 * byte. 68 */ 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. */ 71 void 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; 76 register unsigned long l=length; 77 register int num=numbits/8,n=(numbits+7)/8,i,rem=numbits%8; 78 DES_LONG ti[2]; 79 unsigned char *iv; 80 #ifndef L_ENDIAN 81 unsigned char ovec[16]; 82 #else 83 unsigned int sh[4]; 84 unsigned char *ovec=(unsigned char *)sh; 85 86 /* I kind of count that compiler optimizes away this assertioni,*/ 87 assert (sizeof(sh[0])==4); /* as this holds true for all, */ 88 /* but 16-bit platforms... */ 89 90 #endif 91 92 if (numbits<=0 || numbits > 64) return; 93 iv = &(*ivec)[0]; 94 c2l(iv,v0); 95 c2l(iv,v1); 96 if (enc) 97 { 98 while (l >= (unsigned long)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^=ti[0]; 107 d1^=ti[1]; 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 (numbits == 32) 113 { v0=v1; v1=d0; } 114 else if (numbits == 64) 115 { v0=d0; v1=d1; } 116 else 117 { 118 #ifndef L_ENDIAN 119 iv=&ovec[0]; 120 l2c(v0,iv); 121 l2c(v1,iv); 122 l2c(d0,iv); 123 l2c(d1,iv); 124 #else 125 sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1; 126 #endif 127 if (rem==0) 128 memmove(ovec,ovec+num,8); 129 else 130 for(i=0 ; i < 8 ; ++i) 131 ovec[i]=ovec[i+num]<<rem | 132 ovec[i+num+1]>>(8-rem); 133 #ifdef L_ENDIAN 134 v0=sh[0], v1=sh[1]; 135 #else 136 iv=&ovec[0]; 137 c2l(iv,v0); 138 c2l(iv,v1); 139 #endif 140 } 141 } 142 } 143 else 144 { 145 while (l >= (unsigned long)n) 146 { 147 l-=n; 148 ti[0]=v0; 149 ti[1]=v1; 150 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); 151 c2ln(in,d0,d1,n); 152 in+=n; 153 /* 30-08-94 - eay - changed because l>>32 and 154 * l<<32 are bad under gcc :-( */ 155 if (numbits == 32) 156 { v0=v1; v1=d0; } 157 else if (numbits == 64) 158 { v0=d0; v1=d1; } 159 else 160 { 161 #ifndef L_ENDIAN 162 iv=&ovec[0]; 163 l2c(v0,iv); 164 l2c(v1,iv); 165 l2c(d0,iv); 166 l2c(d1,iv); 167 #else 168 sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1; 169 #endif 170 if (rem==0) 171 memmove(ovec,ovec+num,8); 172 else 173 for(i=0 ; i < 8 ; ++i) 174 ovec[i]=ovec[i+num]<<rem | 175 ovec[i+num+1]>>(8-rem); 176 #ifdef L_ENDIAN 177 v0=sh[0], v1=sh[1]; 178 #else 179 iv=&ovec[0]; 180 c2l(iv,v0); 181 c2l(iv,v1); 182 #endif 183 } 184 d0^=ti[0]; 185 d1^=ti[1]; 186 l2cn(d0,d1,out,n); 187 out+=n; 188 } 189 } 190 iv = &(*ivec)[0]; 191 l2c(v0,iv); 192 l2c(v1,iv); 193 v0=v1=d0=d1=ti[0]=ti[1]=0; 194 } 195 196
