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Diffstat (limited to 'eBones/des/new_rnd_key.c')
| -rw-r--r-- | eBones/des/new_rnd_key.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/eBones/des/new_rnd_key.c b/eBones/des/new_rnd_key.c new file mode 100644 index 0000000..199067b --- /dev/null +++ b/eBones/des/new_rnd_key.c @@ -0,0 +1,210 @@ +/* + * $Source: /usr/src/kerberosIV/des/RCS/new_rnd_key.c,v $ + * $Author: bostic $ + * + * Copyright 1988 by the Massachusetts Institute of Technology. + * + * For copying and distribution information, please see the file + * <mit-copyright.h>. + * + * New pseudo-random key generator, using DES encryption to make the + * pseudo-random cycle as hard to break as DES. + * + * Written by Mark Lillibridge, MIT Project Athena + * + * Under U.S. law, this software may not be exported outside the US + * without license from the U.S. Commerce department. + */ + +#ifndef lint +static char rcsid_new_rnd_key_c[] = +"$Header: /usr/src/kerberosIV/des/RCS/new_rnd_key.c,v 4.2 91/02/25 15:14:22 bostic Exp $"; +#endif lint + +#include <mit-copyright.h> + +#include <des.h> +#include "des_internal.h" + +extern void des_fixup_key_parity(); +extern int des_is_weak_key(); + +void des_set_random_generator_seed(), des_set_sequence_number(); +void des_generate_random_block(); + +/* + * 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) + des_cblock key; +{ + do { + des_generate_random_block(key); + des_fixup_key_parity(key); + } while (des_is_weak_key(key)); + + 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. + */ +#ifndef BSDUNIX + you lose... (aka, you get to implement an analog of this for your + system...) +#else + +#include <sys/time.h> + +void des_init_random_number_generator(key) + des_cblock key; +{ + struct { /* This must be 64 bits exactly */ + long process_id; + long host_id; + } seed; + struct timeval time; /* this must also be 64 bits exactly */ + des_cblock new_key; + long gethostid(); + + /* + * use a host id and process id in generating the seed to ensure + * that different servers have different streams: + */ + seed.host_id = gethostid(); + seed.process_id = getpid(); + + /* + * Generate a tempory value that depends on the key, host_id, and + * process_id such that it gives no useful information about the key: + */ + des_set_random_generator_seed(key); + des_set_sequence_number((unsigned char *)&seed); + des_new_random_key(new_key); + + /* + * use it to select a random stream: + */ + des_set_random_generator_seed(new_key); + + /* + * use a time stamp to ensure that a server started later does not reuse + * an old stream: + */ + gettimeofday(&time, (struct timezone *)0); + des_set_sequence_number((unsigned char *)&time); + + /* + * use the time stamp finally to select the final seed using the + * current random number stream: + */ + des_new_random_key(new_key); + des_set_random_generator_seed(new_key); +} + +#endif /* ifdef BSDUNIX */ + +/* + * 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. + */ + +/* + * The secret des key schedule for the current stream of random numbers: + */ +static des_key_schedule random_sequence_key; + +/* + * The sequence # in the current stream of random numbers: + */ +static unsigned char sequence_number[8]; + +/* + * 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) + des_cblock key; +{ + register int i; + + /* select the new stream: (note errors are not possible here...) */ + des_key_sched(key, random_sequence_key); + + /* "seek" to the start of the stream: */ + for (i=0; i<8; i++) + sequence_number[i] = 0; +} + +/* + * 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) + des_cblock new_sequence_number; +{ + bcopy((char *)new_sequence_number, (char *)sequence_number, + sizeof(sequence_number)); +} + +/* + * des_generate_random_block: routine to return the next random number + * from the current random number stream. + * The returned number is 64 bits long. + * + * Requires: des_set_random_generator_seed must have been called at least once + * before this routine is called. + */ +void des_generate_random_block(block) + des_cblock block; +{ + int i; + + /* + * Encrypt the sequence number to get the new random block: + */ + des_ecb_encrypt(sequence_number, block, random_sequence_key, 1); + + /* + * Increment the sequence number as an 8 byte unsigned number with wrap: + * (using LSB here) + */ + for (i=0; i<8; i++) { + sequence_number[i] = (sequence_number[i] + 1) & 0xff; + if (sequence_number[i]) + break; + } +} |
