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 */
67void des_cfb_encrypt(in, out, numbits, length, schedule, ivec, encrypt)
68unsigned char *in;
69unsigned char *out;
70int numbits;
71long length;
72des_key_schedule schedule;
73des_cblock (*ivec);
74int 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