At long last, an snkkey that will spit out checksum info
when loading your keys...
Sorry took so long to get this posted - had to wait for
permission from the Digital Pathways folks. Many thanks
to mjr and Steve Bellovin for putting up with my constant
queries. Thanks also to jayb @
qsun .
att .
com for the observations
that eventually led to cracking the algorithm used :->
Jeff LaCoursiere
Network Admin
UPRC
Ft. Worth, TX
/**********************************************************************
THE MAGIC WORDS ARE SQUEAMISH OSSIFRAGE
**********************************************************************/
/*-
* Copyright (c) 1993, Trusted Information Systems, Incorporated
* All rights reserved.
*
* Redistribution and use are governed by the terms detailed in the
* license document ("LICENSE") included with the toolkit.
*/
/*
* Author: Marcus J. Ranum, Trusted Information Systems, Inc.
*/
static char RcsId[] = "$Header: snkkey.c,v 1.1 93/10/20 11:14:40 mjr rel $";
#include <stdio.h>
#include <time.h>
extern long random();
#include "des.h"
/*
This is a simple hack to produce pretty random shared
secrets for Digital Pathways SNK units.
mjr.
*/
main()
{
char buf[BUFSIZ];
des_key_schedule keysched;
des_cblock cblock;
char cbuf[12];
int seed,i,j;
long now;
long quad1;
long quad2;
unsigned char *p1,*p2;
unsigned long kval=0;
/* generate a seed from user typomatic */
fprintf(stderr,"Enter a line of text as a seed: ");
fgets(buf,sizeof(buf),stdin);
des_string_to_key(buf,cblock);
des_set_key(cblock,keysched);
des_ecb_encrypt(buf,cbuf,keysched,DES_ENCRYPT);
/* stuff raw cipherstuff into the seed */
bcopy(cbuf,&seed,sizeof(int));
time(&now);
srandom(seed ^ (int)now);
/* that should satisfy casual users */
quad1 = random();
quad2 = random();
p1 = (unsigned char *)&quad1;
p2 = (unsigned char *)&quad2;
/*
* set up key using generated octals
*/
for (i=0; i<4; i++) {
cblock[i]=p1[i];
cblock[i+4]=p2[i];
}
des_set_key(cblock,keysched);
/*
* encrypt string of nulls for checksum
*/
/* zeroize the entire buffer */
for(i = 0; i < 9; i++)
buf[i] = '\0';
des_ecb_encrypt(buf,cbuf,keysched,DES_ENCRYPT);
/* pull some bits out of the ciphertext into a long */
for(i=0; i<4; i++)
for(j = 0; j < 8; j++)
kval = (kval << 1) | ((cbuf[i] >> (7 - j)) & 1);
/*
* make a hex string - strip off last two chars
*/
sprintf(buf,"%08x",kval);
buf[6]='\0'; /* ugly but effective :-> */
printf("Enter into snk:");
printf("%3.3o %3.3o %3.3o %3.3o ",p1[0],p1[1],p1[2],p1[3]);
printf("%3.3o %3.3o %3.3o %3.3o\n",p2[0],p2[1],p2[2],p2[3]);
printf("Checksum: %s\n",buf);
exit(0);
}
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