/* $OpenBSD: ofb_enc.c,v 1.5 2014/06/12 15:49:28 deraadt Exp $ */
/* 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 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_ofb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
long length, DES_key_schedule *schedule,
DES_cblock *ivec)
{
DES_LONG d0,d1,vv0,vv1,v0,v1,n=(numbits+7)/8;
DES_LONG mask0,mask1;
long l=length;
int num=numbits;
DES_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< 0)
{
ti[0]=v0;
ti[1]=v1;
DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
vv0=ti[0];
vv1=ti[1];
c2ln(in,d0,d1,n);
in+=n;
d0=(d0^vv0)&mask0;
d1=(d1^vv1)&mask1;
l2cn(d0,d1,out,n);
out+=n;
if (num == 32)
{ v0=v1; v1=vv0; }
else if (num == 64)
{ v0=vv0; v1=vv1; }
else if (num > 32) /* && num != 64 */
{
v0=((v1>>(num-32))|(vv0<<(64-num)))&0xffffffffL;
v1=((vv0>>(num-32))|(vv1<<(64-num)))&0xffffffffL;
}
else /* num < 32 */
{
v0=((v0>>num)|(v1<<(32-num)))&0xffffffffL;
v1=((v1>>num)|(vv0<<(32-num)))&0xffffffffL;
}
}
iv = &(*ivec)[0];
l2c(v0,iv);
l2c(v1,iv);
v0=v1=d0=d1=ti[0]=ti[1]=vv0=vv1=0;
}