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rc2cfb64.c
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1 /* crypto/rc2/rc2cfb64.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/rc2.h>
60 #include "rc2_locl.h"
61 
62 /* The input and output encrypted as though 64bit cfb 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 
67 void RC2_cfb64_encrypt(const unsigned char *in, unsigned char *out,
68  long length, RC2_KEY *schedule, unsigned char *ivec,
69  int *num, int encrypt)
70  {
71  register unsigned long v0,v1,t;
72  register int n= *num;
73  register long l=length;
74  unsigned long ti[2];
75  unsigned char *iv,c,cc;
76 
77  iv=(unsigned char *)ivec;
78  if (encrypt)
79  {
80  while (l--)
81  {
82  if (n == 0)
83  {
84  c2l(iv,v0); ti[0]=v0;
85  c2l(iv,v1); ti[1]=v1;
86  RC2_encrypt((unsigned long *)ti,schedule);
87  iv=(unsigned char *)ivec;
88  t=ti[0]; l2c(t,iv);
89  t=ti[1]; l2c(t,iv);
90  iv=(unsigned char *)ivec;
91  }
92  c= *(in++)^iv[n];
93  *(out++)=c;
94  iv[n]=c;
95  n=(n+1)&0x07;
96  }
97  }
98  else
99  {
100  while (l--)
101  {
102  if (n == 0)
103  {
104  c2l(iv,v0); ti[0]=v0;
105  c2l(iv,v1); ti[1]=v1;
106  RC2_encrypt((unsigned long *)ti,schedule);
107  iv=(unsigned char *)ivec;
108  t=ti[0]; l2c(t,iv);
109  t=ti[1]; l2c(t,iv);
110  iv=(unsigned char *)ivec;
111  }
112  cc= *(in++);
113  c=iv[n];
114  iv[n]=cc;
115  *(out++)=c^cc;
116  n=(n+1)&0x07;
117  }
118  }
119  v0=v1=ti[0]=ti[1]=t=c=cc=0;
120  *num=n;
121  }
122