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/* crypto/des/cfb64enc.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.]
*/
#include "des_locl.h"
/*
* The input and output encrypted as though 64bit cfb mode is being used.
* The extra state information to record how much of the 64bit block we have
* used is contained in *num;
*/
void DES_cfb64_encrypt(const unsigned char *in, unsigned char *out,
long length, DES_key_schedule *schedule,
DES_cblock *ivec, int *num, int enc)
{
register DES_LONG v0, v1;
register long l = length;
register int n = *num;
DES_LONG ti[2];
unsigned char *iv, c, cc;
iv = &(*ivec)[0];
if (enc) {
while (l--) {
if (n == 0) {
c2l(iv, v0);
ti[0] = v0;
c2l(iv, v1);
ti[1] = v1;
DES_encrypt1(ti, schedule, DES_ENCRYPT);
iv = &(*ivec)[0];
v0 = ti[0];
l2c(v0, iv);
v0 = ti[1];
l2c(v0, iv);
iv = &(*ivec)[0];
}
c = *(in++) ^ iv[n];
*(out++) = c;
iv[n] = c;
n = (n + 1) & 0x07;
}
} else {
while (l--) {
if (n == 0) {
c2l(iv, v0);
ti[0] = v0;
c2l(iv, v1);
ti[1] = v1;
DES_encrypt1(ti, schedule, DES_ENCRYPT);
iv = &(*ivec)[0];
v0 = ti[0];
l2c(v0, iv);
v0 = ti[1];
l2c(v0, iv);
iv = &(*ivec)[0];
}
cc = *(in++);
c = iv[n];
iv[n] = cc;
*(out++) = c ^ cc;
n = (n + 1) & 0x07;
}
}
v0 = v1 = ti[0] = ti[1] = c = cc = 0;
*num = n;
}
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