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/*
* lib/des425/new_rnd_key.c
*
* Copyright 1988,1990 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
*/
#include "des.h"
krb5_pointer des425_random_state = 0;
/*
* des_new_random_key: create a random des key
*
* Requires: des_set_random_number_generater_seed must be at called least
* once before this routine is called.
*
* Notes: the returned key has correct parity and is guarenteed not
* to be a weak des key. Des_generate_random_block is used to
* provide the random bits.
*/
int
des_new_random_key(key)
mit_des_cblock key;
{
krb5_keyblock * keyblock;
krb5_error_code kret;
kret = mit_des_random_key(NULL, des425_random_state, &keyblock);
if (kret) return kret;
memcpy(key, keyblock->contents, sizeof(mit_des_cblock));
krb5_free_keyblock(NULL, keyblock);
return 0;
}
/*
* des_init_random_number_generator:
*
* This routine takes a secret key possibly shared by a number
* of servers and uses it to generate a random number stream that is
* not shared by any of the other servers. It does this by using the current
* process id, host id, and the current time to the nearest second. The
* resulting stream seed is not useful information for cracking the secret
* key. Moreover, this routine keeps no copy of the secret key.
* This routine is used for example, by the kerberos server(s) with the
* key in question being the kerberos master key.
*
* Note: this routine calls des_set_random_generator_seed.
*/
void
des_init_random_number_generator(key)
mit_des_cblock key;
{
krb5_keyblock keyblock;
krb5_encrypt_block eblock;
krb5_use_enctype(NULL, &eblock, ENCTYPE_DES_CBC_CRC);
keyblock.enctype = ENCTYPE_DES_CBC_CRC;
keyblock.length = sizeof(mit_des_cblock);
keyblock.contents = (krb5_octet *)key;
if (des425_random_state)
mit_des_finish_random_key(&eblock, &des425_random_state);
mit_des_init_random_key(&eblock, &keyblock, &des425_random_state);
}
/*
* This module implements a random number generator faculty such that the next
* number in any random number stream is very hard to predict without knowing
* the seed for that stream even given the preceeding random numbers.
*/
/*
* des_set_random_generator_seed: this routine is used to select a random
* number stream. The stream that results is
* totally determined by the passed in key.
* (I.e., calling this routine again with the
* same key allows repeating a sequence of
* random numbers)
*
* Requires: key is a valid des key. I.e., has correct parity and is not a
* weak des key.
*/
void
des_set_random_generator_seed(key)
mit_des_cblock key;
{
krb5_data seed;
seed.length = sizeof(mit_des_cblock);
seed.data = (krb5_pointer) key;
if (!des425_random_state)
des_init_random_number_generator(key);
mit_des_set_random_generator_seed(&seed, des425_random_state);
}
/*
* des_set_sequence_number: this routine is used to set the sequence number
* of the current random number stream. This routine
* may be used to "seek" within the current random
* number stream.
*
* Note that des_set_random_generator_seed resets the sequence number to 0.
*/
void
des_set_sequence_number(new_sequence_number)
mit_des_cblock new_sequence_number;
{
krb5_data sequence;
sequence.length = sizeof(new_sequence_number);
sequence.data = (char FAR *)new_sequence_number;
mit_des_set_random_sequence_number(&sequence, des425_random_state);
}
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