bf_cfb64.c revision bdfb8ad83da0647e9b9a32792598e8ce7ba3ef4d 
1/* crypto/bf/bf_cfb64.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/blowfish.h>
60#include "bf_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
67void BF_cfb64_encrypt(const unsigned char *in, unsigned char *out, long length,
68	     const BF_KEY *schedule, unsigned char *ivec, int *num, int encrypt)
69	{
70	register BF_LONG v0,v1,t;
71	register int n= *num;
72	register long l=length;
73	BF_LONG ti[2];
74	unsigned char *iv,c,cc;
75
76	iv=(unsigned char *)ivec;
77	if (encrypt)
78		{
79		while (l--)
80			{
81			if (n == 0)
82				{
83				n2l(iv,v0); ti[0]=v0;
84				n2l(iv,v1); ti[1]=v1;
85				BF_encrypt((BF_LONG *)ti,schedule);
86				iv=(unsigned char *)ivec;
87				t=ti[0]; l2n(t,iv);
88				t=ti[1]; l2n(t,iv);
89				iv=(unsigned char *)ivec;
90				}
91			c= *(in++)^iv[n];
92			*(out++)=c;
93			iv[n]=c;
94			n=(n+1)&0x07;
95			}
96		}
97	else
98		{
99		while (l--)
100			{
101			if (n == 0)
102				{
103				n2l(iv,v0); ti[0]=v0;
104				n2l(iv,v1); ti[1]=v1;
105				BF_encrypt((BF_LONG *)ti,schedule);
106				iv=(unsigned char *)ivec;
107				t=ti[0]; l2n(t,iv);
108				t=ti[1]; l2n(t,iv);
109				iv=(unsigned char *)ivec;
110				}
111			cc= *(in++);
112			c=iv[n];
113			iv[n]=cc;
114			*(out++)=c^cc;
115			n=(n+1)&0x07;
116			}
117		}
118	v0=v1=ti[0]=ti[1]=t=c=cc=0;
119	*num=n;
120	}
121
122