Line data Source code
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 : /*
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.
68 : */
69 : /*
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.
72 : */
73 0 : 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)
76 : {
77 : register DES_LONG d0, d1, v0, v1;
78 0 : register unsigned long l = length;
79 0 : register int num = numbits / 8, n = (numbits + 7) / 8, i, rem =
80 : numbits % 8;
81 : DES_LONG ti[2];
82 : unsigned char *iv;
83 : #ifndef L_ENDIAN
84 : unsigned char ovec[16];
85 : #else
86 : unsigned int sh[4];
87 : unsigned char *ovec = (unsigned char *)sh;
88 :
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... */
92 :
93 : #endif
94 :
95 0 : if (numbits <= 0 || numbits > 64)
96 0 : return;
97 : iv = &(*ivec)[0];
98 0 : c2l(iv, v0);
99 0 : c2l(iv, v1);
100 0 : if (enc) {
101 0 : while (l >= (unsigned long)n) {
102 0 : l -= n;
103 0 : ti[0] = v0;
104 0 : ti[1] = v1;
105 0 : DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT);
106 0 : c2ln(in, d0, d1, n);
107 0 : in += n;
108 0 : d0 ^= ti[0];
109 0 : d1 ^= ti[1];
110 0 : l2cn(d0, d1, out, n);
111 0 : out += n;
112 : /*
113 : * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
114 : * gcc :-(
115 : */
116 0 : if (numbits == 32) {
117 : v0 = v1;
118 : v1 = d0;
119 0 : } else if (numbits == 64) {
120 : v0 = d0;
121 : v1 = d1;
122 : } else {
123 : #ifndef L_ENDIAN
124 : iv = &ovec[0];
125 : l2c(v0, iv);
126 : l2c(v1, iv);
127 : l2c(d0, iv);
128 : l2c(d1, iv);
129 : #else
130 0 : sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1;
131 : #endif
132 0 : if (rem == 0)
133 0 : memmove(ovec, ovec + num, 8);
134 : else
135 0 : for (i = 0; i < 8; ++i)
136 0 : ovec[i] = ovec[i + num] << rem |
137 0 : ovec[i + num + 1] >> (8 - rem);
138 : #ifdef L_ENDIAN
139 0 : v0 = sh[0], v1 = sh[1];
140 : #else
141 : iv = &ovec[0];
142 : c2l(iv, v0);
143 : c2l(iv, v1);
144 : #endif
145 : }
146 : }
147 : } else {
148 0 : while (l >= (unsigned long)n) {
149 0 : l -= n;
150 0 : ti[0] = v0;
151 0 : ti[1] = v1;
152 0 : DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT);
153 0 : c2ln(in, d0, d1, n);
154 0 : in += n;
155 : /*
156 : * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
157 : * gcc :-(
158 : */
159 0 : if (numbits == 32) {
160 : v0 = v1;
161 : v1 = d0;
162 0 : } else if (numbits == 64) {
163 : v0 = d0;
164 : v1 = d1;
165 : } else {
166 : #ifndef L_ENDIAN
167 : iv = &ovec[0];
168 : l2c(v0, iv);
169 : l2c(v1, iv);
170 : l2c(d0, iv);
171 : l2c(d1, iv);
172 : #else
173 0 : sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1;
174 : #endif
175 0 : if (rem == 0)
176 0 : memmove(ovec, ovec + num, 8);
177 : else
178 0 : for (i = 0; i < 8; ++i)
179 0 : ovec[i] = ovec[i + num] << rem |
180 0 : ovec[i + num + 1] >> (8 - rem);
181 : #ifdef L_ENDIAN
182 0 : v0 = sh[0], v1 = sh[1];
183 : #else
184 : iv = &ovec[0];
185 : c2l(iv, v0);
186 : c2l(iv, v1);
187 : #endif
188 : }
189 0 : d0 ^= ti[0];
190 0 : d1 ^= ti[1];
191 0 : l2cn(d0, d1, out, n);
192 0 : out += n;
193 : }
194 : }
195 : iv = &(*ivec)[0];
196 0 : l2c(v0, iv);
197 0 : l2c(v1, iv);
198 : v0 = v1 = d0 = d1 = ti[0] = ti[1] = 0;
199 : }
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