freebsd-src/eBones/des/qud_cksm.c
Geoff Rehmet 60643d379b Initial import of eBones.
(Including all changes for FreeBSD - importing the original eBones distribution
would be too complex at this stage, since I don't have access to Piero's 
CVS.)
(If you want to include eBones in your system, don't forget to include
MAKE_EBONES in /etc/make.conf.)
(This stuff is now also suppable from braae.ru.ac.za.)

Bones originally from MIT SIPB.
Original port to FreeBSD 1.x  by Piero Serini.
Moved to FreeBSD 2.0 by Doug Rabson and Geoff Rehmet.
Nice bug fixes from Doug Rabson.
1994-09-30 14:50:09 +00:00

94 lines
2.1 KiB
C

/* qud_cksm.c */
/* Copyright (C) 1993 Eric Young - see README for more details */
/*-
* $Id: qud_cksm.c,v 1.2 1994/07/19 19:22:02 g89r4222 Exp $
*/
/* From "Message Authentication" R.R. Jueneman, S.M. Matyas, C.H. Meyer
* IEEE Communications Magazine Sept 1985 Vol. 23 No. 9 p 29-40
* This module in only based on the code in this paper and is
* almost definitely not the same as the MIT implementation.
*/
#include "des_locl.h"
/* bug fix for dos - 7/6/91 - Larry hughes@logos.ucs.indiana.edu */
#define B0(a) (((unsigned long)(a)))
#define B1(a) (((unsigned long)(a))<<8)
#define B2(a) (((unsigned long)(a))<<16)
#define B3(a) (((unsigned long)(a))<<24)
/* used to scramble things a bit */
/* Got the value MIT uses via brute force :-) 2/10/90 eay */
#define NOISE ((unsigned long)83653421)
unsigned long des_quad_cksum(input,output,length,out_count,seed)
des_cblock *input;
des_cblock *output;
long length;
int out_count;
des_cblock *seed;
{
unsigned long z0,z1,t0,t1;
int i;
long l=0;
unsigned char *cp;
unsigned char *lp;
if (out_count < 1) out_count=1;
lp=(unsigned char *)output;
z0=B0((*seed)[0])|B1((*seed)[1])|B2((*seed)[2])|B3((*seed)[3]);
z1=B0((*seed)[4])|B1((*seed)[5])|B2((*seed)[6])|B3((*seed)[7]);
for (i=0; ((i<4)&&(i<out_count)); i++)
{
cp=(unsigned char *)input;
l=length;
while (l > 0)
{
if (l > 1)
{
t0= (unsigned long)(*(cp++));
t0|=(unsigned long)B1(*(cp++));
l--;
}
else
t0= (unsigned long)(*(cp++));
l--;
/* add */
t0+=z0;
t0&=0xffffffff;
t1=z1;
/* square, well sort of square */
z0=((((t0*t0)&0xffffffff)+((t1*t1)&0xffffffff))
&0xffffffff)%0x7fffffff;
z1=((t0*((t1+NOISE)&0xffffffff))&0xffffffff)%0x7fffffff;
}
if (lp != NULL)
{
/* I believe I finally have things worked out.
* The MIT library assumes that the checksum
* is one huge number and it is returned in a
* host dependant byte order.
*/
static unsigned long l=1;
static unsigned char *c=(unsigned char *)&l;
if (c[0])
{
l2c(z0,lp);
l2c(z1,lp);
}
else
{
lp=output[out_count-i-1];
l2n(z1,lp);
l2n(z0,lp);
}
}
}
return(z0);
}