1 /* crypto/des/cfb_enc.c */
2 /* Copyright (C) 1995-1997 Eric Young (eay@mincom.oz.au)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@mincom.oz.au).
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@mincom.oz.au).
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@mincom.oz.au)"
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@mincom.oz.au)"
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 */
des_cfb_encrypt(in,out,numbits,length,schedule,ivec,encrypt)67 void des_cfb_encrypt(in, out, numbits, length, schedule, ivec, encrypt)
68 unsigned char *in;
69 unsigned char *out;
70 int numbits;
71 long length;
72 des_key_schedule schedule;
73 des_cblock (*ivec);
74 int encrypt;
75 {
76 register DES_LONG d0,d1,v0,v1,n=(numbits+7)/8;
77 register DES_LONG mask0,mask1;
78 register unsigned long l=length;
79 register int num=numbits;
80 DES_LONG ti[2];
81 unsigned char *iv;
82
83 if (num > 64) return;
84 if (num > 32)
85 {
86 mask0=0xffffffffL;
87 if (num == 64)
88 mask1=mask0;
89 else mask1=(1L<<(num-32))-1;
90 }
91 else
92 {
93 if (num == 32)
94 mask0=0xffffffffL;
95 else mask0=(1L<<num)-1;
96 mask1=0x00000000;
97 }
98
99 iv=(unsigned char *)ivec;
100 c2l(iv,v0);
101 c2l(iv,v1);
102 if (encrypt)
103 {
104 while (l >= n)
105 {
106 l-=n;
107 ti[0]=v0;
108 ti[1]=v1;
109 des_encrypt((DES_LONG *)ti,schedule,DES_ENCRYPT);
110 c2ln(in,d0,d1,n);
111 in+=n;
112 d0=(d0^ti[0])&mask0;
113 d1=(d1^ti[1])&mask1;
114 l2cn(d0,d1,out,n);
115 out+=n;
116 /* 30-08-94 - eay - changed because l>>32 and
117 * l<<32 are bad under gcc :-( */
118 if (num == 32)
119 { v0=v1; v1=d0; }
120 else if (num == 64)
121 { v0=d0; v1=d1; }
122 else if (num > 32) /* && num != 64 */
123 {
124 v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL;
125 v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL;
126 }
127 else /* num < 32 */
128 {
129 v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
130 v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL;
131 }
132 }
133 }
134 else
135 {
136 while (l >= n)
137 {
138 l-=n;
139 ti[0]=v0;
140 ti[1]=v1;
141 des_encrypt((DES_LONG *)ti,schedule,DES_ENCRYPT);
142 c2ln(in,d0,d1,n);
143 in+=n;
144 /* 30-08-94 - eay - changed because l>>32 and
145 * l<<32 are bad under gcc :-( */
146 if (num == 32)
147 { v0=v1; v1=d0; }
148 else if (num == 64)
149 { v0=d0; v1=d1; }
150 else if (num > 32) /* && num != 64 */
151 {
152 v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL;
153 v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL;
154 }
155 else /* num < 32 */
156 {
157 v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
158 v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL;
159 }
160 d0=(d0^ti[0])&mask0;
161 d1=(d1^ti[1])&mask1;
162 l2cn(d0,d1,out,n);
163 out+=n;
164 }
165 }
166 iv=(unsigned char *)ivec;
167 l2c(v0,iv);
168 l2c(v1,iv);
169 v0=v1=d0=d1=ti[0]=ti[1]=0;
170 }
171
172