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 #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 }