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/*
* $Source$
* $Author$
*
* Copyright 1985, 1986, 1987, 1988, 1989 by the Massachusetts Institute
* of Technology.
*
* For copying and distribution information, please see the file
* <mit-copyright.h>.
*
* These routines perform encryption and decryption using the DES
* private key algorithm, or else a subset of it-- fewer inner loops.
* (AUTH_DES_ITER defaults to 16, may be less.)
*
* Under U.S. law, this software may not be exported outside the US
* without license from the U.S. Commerce department.
*
* The key schedule is passed as an arg, as well as the cleartext or
* ciphertext. The cleartext and ciphertext should be in host order.
*
* These routines form the library interface to the DES facilities.
*
* spm 8/85 MIT project athena
*/
#ifndef lint
static char rcsid_string_to_key_c[] =
"$Id$";
#endif
#include <mit-copyright.h>
#include <stdio.h>
#include <des.h>
extern int des_debug;
extern int des_debug_print();
extern void des_fixup_key_parity();
/*
* convert an arbitrary length string to a DES key
*/
int
des_string_to_key(str,key)
char *str;
register des_cblock *key;
{
register char *in_str;
register unsigned temp,i;
register int j;
register long length;
static unsigned char *k_p;
static int forward;
register char *p_char;
static char k_char[64];
static des_key_schedule key_sked;
extern unsigned long des_cbc_cksum();
in_str = str;
forward = 1;
p_char = k_char;
length = strlen(str);
/* init key array for bits */
memset(k_char, 0, sizeof(k_char));
#ifdef DEBUG
if (des_debug)
fprintf(stdout,
"\n\ninput str length = %d string = %s\nstring = 0x ",
length,str);
#endif
/* get next 8 bytes, strip parity, xor */
for (i = 1; i <= length; i++) {
/* get next input key byte */
temp = (unsigned int) *str++;
#ifdef DEBUG
if (des_debug)
fprintf(stdout,"%02x ",temp & 0xff);
#endif
/* loop through bits within byte, ignore parity */
for (j = 0; j <= 6; j++) {
if (forward)
*p_char++ ^= (int) temp & 01;
else
*--p_char ^= (int) temp & 01;
temp = temp >> 1;
} while (--j > 0);
/* check and flip direction */
if ((i%8) == 0)
forward = !forward;
}
/* now stuff into the key des_cblock, and force odd parity */
p_char = k_char;
k_p = (unsigned char *) key;
for (i = 0; i <= 7; i++) {
temp = 0;
for (j = 0; j <= 6; j++)
temp |= *p_char++ << (1+j);
*k_p++ = (unsigned char) temp;
}
/* fix key parity */
des_fixup_key_parity(key);
/* Now one-way encrypt it with the folded key */
(void) des_key_sched(key,key_sked);
(void) des_cbc_cksum((des_cblock *)in_str,key,length,key_sked,key);
/* erase key_sked */
memset((char *)key_sked, 0, sizeof(key_sked));
/* now fix up key parity again */
des_fixup_key_parity(key);
if (des_debug)
fprintf(stdout,
"\nResulting string_to_key = 0x%x 0x%x\n",
*((unsigned long *) key),
*((unsigned long *) key+1));
}
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