diff options
Diffstat (limited to 'package/ead/src/tinysrp/t_truerand.c')
| -rw-r--r-- | package/ead/src/tinysrp/t_truerand.c | 151 |
1 files changed, 0 insertions, 151 deletions
diff --git a/package/ead/src/tinysrp/t_truerand.c b/package/ead/src/tinysrp/t_truerand.c deleted file mode 100644 index fa0d6ce603..0000000000 --- a/package/ead/src/tinysrp/t_truerand.c +++ /dev/null @@ -1,151 +0,0 @@ -/* - * Physically random numbers (very nearly uniform) - * D. P. Mitchell - * Modified by Matt Blaze 7/95 - */ -/* - * The authors of this software are Don Mitchell and Matt Blaze. - * Copyright (c) 1995 by AT&T. - * Permission to use, copy, and modify this software without fee - * is hereby granted, provided that this entire notice is included in - * all copies of any software which is or includes a copy or - * modification of this software and in all copies of the supporting - * documentation for such software. - * - * This software may be subject to United States export controls. - * - * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED - * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR AT&T MAKE ANY - * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY - * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. - */ - -/* - * WARNING: depending on the particular platform, raw_truerand() - * output may be biased or correlated. In general, you can expect - * about 16 bits of "pseudo-entropy" out of each 32 bit word returned - * by truerand(), but it may not be uniformly diffused. You should - * raw_therefore run the output through some post-whitening function - * (like MD5 or DES or whatever) before using it to generate key - * material. (RSAREF's random package does this for you when you feed - * raw_truerand() bits to the seed input function.) - * - * The application interface, for 8, 16, and 32 bit properly "whitened" - * random numbers, can be found in trand8(), trand16(), and trand32(). - * Use those instead of calling raw_truerand() directly. - * - * The basic idea here is that between clock "skew" and various - * hard-to-predict OS event arrivals, counting a tight loop will yield - * a little (maybe a third of a bit or so) of "good" randomness per - * interval clock tick. This seems to work well even on unloaded - * machines. If there is a human operator at the machine, you should - * augment truerand with other measure, like keyboard event timing. - * On server machines (e.g., when you need to generate a - * Diffie-Hellman secret) truerand alone may be good enough. - * - * Test these assumptions on your own platform before fielding a - * system based on this software or these techniques. - * - * This software seems to work well (at 10 or so bits per - * raw_truerand() call) on a Sun Sparc-20 under SunOS 4.1.3 and on a - * P100 under BSDI 2.0. You're on your own elsewhere. - * - */ - -#include "t_defines.h" - -#include <signal.h> -#include <setjmp.h> -#include <sys/time.h> -#include <math.h> -#include <stdio.h> - -#ifdef OLD_TRUERAND -static jmp_buf env; -#endif -static unsigned volatile count -#ifndef OLD_TRUERAND - , done = 0 -#endif -; - -static unsigned ocount; -static unsigned buffer; - -static void -tick() -{ - struct itimerval it, oit; - - it.it_interval.tv_sec = 0; - it.it_interval.tv_usec = 0; - it.it_value.tv_sec = 0; - it.it_value.tv_usec = 16665; - if (setitimer(ITIMER_REAL, &it, &oit) < 0) - perror("tick"); -} - -static void -interrupt() -{ - if (count) { -#ifdef OLD_TRUERAND - longjmp(env, 1); -#else - ++done; - return; -#endif - } - - (void) signal(SIGALRM, interrupt); - tick(); -} - -static unsigned long -roulette() -{ -#ifdef OLD_TRUERAND - if (setjmp(env)) { - count ^= (count>>3) ^ (count>>6) ^ ocount; - count &= 0x7; - ocount=count; - buffer = (buffer<<3) ^ count; - return buffer; - } -#else - done = 0; -#endif - (void) signal(SIGALRM, interrupt); - count = 0; - tick(); -#ifdef OLD_TRUERAND - for (;;) -#else - while(done == 0) -#endif - count++; /* about 1 MHz on VAX 11/780 */ -#ifndef OLD_TRUERAND - count ^= (count>>3) ^ (count>>6) ^ ocount; - count &= 0x7; - ocount=count; - buffer = (buffer<<3) ^ count; - return buffer; -#endif -} - -unsigned long -raw_truerand() -{ - count=0; - (void) roulette(); - (void) roulette(); - (void) roulette(); - (void) roulette(); - (void) roulette(); - (void) roulette(); - (void) roulette(); - (void) roulette(); - (void) roulette(); - (void) roulette(); - return roulette(); -} |