1 /* crypto/des/cfb_enc.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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.
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).
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.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
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)"
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
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.]
64 * The input and output are loaded in multiples of 8 bits. What this means is
65 * that if you hame numbits=12 and length=2 the first 12 bits will be
66 * retrieved from the first byte and half the second. The second 12 bits
67 * will come from the 3rd and half the 4th byte.
70 * Until Aug 1 2003 this function did not correctly implement CFB-r, so it
71 * will not be compatible with any encryption prior to that date. Ben.
73 void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
74 long length, DES_key_schedule *schedule,
75 DES_cblock *ivec, int enc)
77 register DES_LONG d0, d1, v0, v1;
78 register unsigned long l = length;
79 register int num = numbits / 8, n = (numbits + 7) / 8, i, rem =
84 unsigned char ovec[16];
87 unsigned char *ovec = (unsigned char *)sh;
89 /* I kind of count that compiler optimizes away this assertioni, */
90 assert(sizeof(sh[0]) == 4); /* as this holds true for all, */
91 /* but 16-bit platforms... */
95 if (numbits <= 0 || numbits > 64)
101 while (l >= (unsigned long)n) {
105 DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT);
110 l2cn(d0, d1, out, n);
113 * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
119 } else if (numbits == 64) {
130 sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1;
133 memmove(ovec, ovec + num, 8);
135 for (i = 0; i < 8; ++i)
136 ovec[i] = ovec[i + num] << rem |
137 ovec[i + num + 1] >> (8 - rem);
139 v0 = sh[0], v1 = sh[1];
148 while (l >= (unsigned long)n) {
152 DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT);
156 * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
162 } else if (numbits == 64) {
173 sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1;
176 memmove(ovec, ovec + num, 8);
178 for (i = 0; i < 8; ++i)
179 ovec[i] = ovec[i + num] << rem |
180 ovec[i + num + 1] >> (8 - rem);
182 v0 = sh[0], v1 = sh[1];
191 l2cn(d0, d1, out, n);
198 v0 = v1 = d0 = d1 = ti[0] = ti[1] = 0;