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c_ofb64.c
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1 /* crypto/cast/c_ofb64.c */
2 /* Copyright (C) 1995-1998 Eric Young ([email protected])
3  * All rights reserved.
4  *
5  * This package is an SSL implementation written
6  * by Eric Young ([email protected]).
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 ([email protected]).
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 ([email protected])"
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 ([email protected])"
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  }