1 /* crypto/cast/c_ofb64.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 <openssl/cast.h>
60 #include "cast_lcl.h"
61
62 /* The input and output encrypted as though 64bit ofb mode is being
63 * used. The extra state information to record how much of the
64 * 64bit block we have used is contained in *num;
65 */
66 void CAST_ofb64_encrypt(const unsigned char *in, unsigned char *out,
67 long length, const CAST_KEY *schedule, unsigned char *ivec,
68 int *num)
69 {
70 register CAST_LONG v0,v1,t;
71 register int n= *num;
72 register long l=length;
73 unsigned char d[8];
74 register char *dp;
75 CAST_LONG ti[2];
76 unsigned char *iv;
77 int save=0;
78
79 iv=ivec;
80 n2l(iv,v0);
81 n2l(iv,v1);
82 ti[0]=v0;
83 ti[1]=v1;
84 dp=(char *)d;
85 l2n(v0,dp);
86 l2n(v1,dp);
87 while (l--)
88 {
89 if (n == 0)
90 {
91 CAST_encrypt((CAST_LONG *)ti,schedule);
92 dp=(char *)d;
93 t=ti[0]; l2n(t,dp);
94 t=ti[1]; l2n(t,dp);
95 save++;
96 }
97 *(out++)= *(in++)^d[n];
98 n=(n+1)&0x07;
99 }
100 if (save)
101 {
102 v0=ti[0];
103 v1=ti[1];
104 iv=ivec;
105 l2n(v0,iv);
106 l2n(v1,iv);
107 }
108 t=v0=v1=ti[0]=ti[1]=0;
109 *num=n;
110 }