/* crypto/des/cfb_enc.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 "e_os.h"
#include "des_locl.h"
#include <assert.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.
*/
/* Until Aug 1 2003 this function did not correctly implement CFB-r, so it
* will not be compatible with any encryption prior to that date. Ben. */
void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
long length, DES_key_schedule *schedule, DES_cblock *ivec,
int enc)
{
register DES_LONG d0,d1,v0,v1;
register unsigned long l=length;
register int num=numbits/8,n=(numbits+7)/8,i,rem=numbits%8;
DES_LONG ti[2];
unsigned char *iv;
#ifndef L_ENDIAN
unsigned char ovec[16];
#else
unsigned int sh[4];
unsigned char *ovec=(unsigned char *)sh;
/* I kind of count that compiler optimizes away this assertioni,*/
assert (sizeof(sh[0])==4); /* as this holds true for all, */
/* but 16-bit platforms... */
#endif
if (numbits<=0 || numbits > 64) return;
iv = &(*ivec)[0];
c2l(iv,v0);
c2l(iv,v1);
if (enc)
{
while (l >= (unsigned long)n)
{
l-=n;
ti[0]=v0;
ti[1]=v1;
DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
c2ln(in,d0,d1,n);
in+=n;
d0^=ti[0];
d1^=ti[1];
l2cn(d0,d1,out,n);
out+=n;
/* 30-08-94 - eay - changed because l>>32 and
* l<<32 are bad under gcc :-( */
if (numbits == 32)
{ v0=v1; v1=d0; }
else if (numbits == 64)
{ v0=d0; v1=d1; }
else
{
#ifndef L_ENDIAN
iv=&ovec[0];
l2c(v0,iv);
l2c(v1,iv);
l2c(d0,iv);
l2c(d1,iv);
#else
sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1;
#endif
if (rem==0)
memmove(ovec,ovec+num,8);
else
for(i=0 ; i < 8 ; ++i)
ovec[i]=ovec[i+num]<<rem |
ovec[i+num+1]>>(8-rem);
#ifdef L_ENDIAN
v0=sh[0], v1=sh[1];
#else
iv=&ovec[0];
c2l(iv,v0);
c2l(iv,v1);
#endif
}
}
}
else
{
while (l >= (unsigned long)n)
{
l-=n;
ti[0]=v0;
ti[1]=v1;
DES_encrypt1((DES_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 (numbits == 32)
{ v0=v1; v1=d0; }
else if (numbits == 64)
{ v0=d0; v1=d1; }
else
{
#ifndef L_ENDIAN
iv=&ovec[0];
l2c(v0,iv);
l2c(v1,iv);
l2c(d0,iv);
l2c(d1,iv);
#else
sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1;
#endif
if (rem==0)
memmove(ovec,ovec+num,8);
else
for(i=0 ; i < 8 ; ++i)
ovec[i]=ovec[i+num]<<rem |
ovec[i+num+1]>>(8-rem);
#ifdef L_ENDIAN
v0=sh[0], v1=sh[1];
#else
iv=&ovec[0];
c2l(iv,v0);
c2l(iv,v1);
#endif
}
d0^=ti[0];
d1^=ti[1];
l2cn(d0,d1,out,n);
out+=n;
}
}
iv = &(*ivec)[0];
l2c(v0,iv);
l2c(v1,iv);
v0=v1=d0=d1=ti[0]=ti[1]=0;
}