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/* lib/des/cfb_enc.c */
/* Copyright (C) 1995 Eric Young (eay@mincom.oz.au)
* All rights reserved.
*
* This file is part of an SSL implementation written
* by Eric Young (eay@mincom.oz.au).
* The implementation was written so as to conform with Netscapes SSL
* specification. This library and applications are
* FREE FOR COMMERCIAL AND NON-COMMERCIAL USE
* as long as the following conditions are aheared to.
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed. If this code is used in a product,
* Eric Young should be given attribution as the author of the parts 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 software developed by Eric Young (eay@mincom.oz.au)
*
* 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 are loaded in multiples of 8 bits.
* What this means is that if you hame numbits=12 and length=2
* the first 12 bits will be retrieved from the first byte and half
* the second. The second 12 bits will come from the 3rd and half the 4th
* byte.
*/
void des_cfb_encrypt(in, out, numbits, length, schedule, ivec, encrypt)
unsigned char *in;
unsigned char *out;
int numbits;
long length;
des_key_schedule schedule;
des_cblock (*ivec);
int encrypt;
{
register unsigned long d0,d1,v0,v1,n=(numbits+7)/8;
register unsigned long mask0,mask1;
register unsigned long l=length;
register int num=numbits;
unsigned long ti[2];
unsigned char *iv;
if (num > 64) return;
if (num > 32)
{
mask0=0xffffffffL;
if (num == 64)
mask1=mask0;
else mask1=(1L<<(num-32))-1;
}
else
{
if (num == 32)
mask0=0xffffffffL;
else mask0=(1L<<num)-1;
mask1=0x00000000;
}
iv=(unsigned char *)ivec;
c2l(iv,v0);
c2l(iv,v1);
if (encrypt)
{
while (l >= n)
{
l-=n;
ti[0]=v0;
ti[1]=v1;
des_encrypt((unsigned long *)ti,schedule,DES_ENCRYPT);
c2ln(in,d0,d1,n);
in+=n;
d0=(d0^ti[0])&mask0;
d1=(d1^ti[1])&mask1;
l2cn(d0,d1,out,n);
out+=n;
/* 30-08-94 - eay - changed because l>>32 and
* l<<32 are bad under gcc :-( */
if (num == 32)
{ v0=v1; v1=d0; }
else if (num == 64)
{ v0=d0; v1=d1; }
else if (num > 32) /* && num != 64 */
{
v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL;
v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL;
}
else /* num < 32 */
{
v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL;
}
}
}
else
{
while (l >= n)
{
l-=n;
ti[0]=v0;
ti[1]=v1;
des_encrypt((unsigned long *)ti,schedule,DES_ENCRYPT);
c2ln(in,d0,d1,n);
in+=n;
/* 30-08-94 - eay - changed because l>>32 and
* l<<32 are bad under gcc :-( */
if (num == 32)
{ v0=v1; v1=d0; }
else if (num == 64)
{ v0=d0; v1=d1; }
else if (num > 32) /* && num != 64 */
{
v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffffL;
v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffffL;
}
else /* num < 32 */
{
v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
v1=((v1>>num)|(d0<<(32-num)))&0xffffffffL;
}
d0=(d0^ti[0])&mask0;
d1=(d1^ti[1])&mask1;
l2cn(d0,d1,out,n);
out+=n;
}
}
iv=(unsigned char *)ivec;
l2c(v0,iv);
l2c(v1,iv);
v0=v1=d0=d1=ti[0]=ti[1]=0;
}
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