[2274] in cryptography@c2.net mail archive
RSA patent countdown clock, in C.
daemon@ATHENA.MIT.EDU (Perry E. Metzger)
Thu Mar 12 12:09:04 1998
To: cryptography@c2.net
Reply-To: perry@piermont.com
From: "Perry E. Metzger" <perry@piermont.com>
Date: 12 Mar 1998 12:07:47 -0500
I thought this might be of some interest. I hope someone will correct
me if I have the date wrong or otherwise screwed up. I'm curious as to
what sort of applications people find for this routine...
Perry
----------------------------------------------------------------------
/*
* RSA patent countdown clock.
* Written March 11, 1998 by Perry E. Metzger
* Public Domain -- This code has no copyright, do anything you like
* to it, though it would be friendly if you gave me credit somewhere.
*/
#include <stdio.h>
#include <time.h>
#include <sys/time.h>
#define SECSPERDAY (24 * 60 * 60)
int
main(int argc, char **argv)
{
struct tm patexp_tm;
time_t exptime, nowtime, diff;
int days;
/*
* should we set the timezone? Which one? Does the patent
* expire at 00:00 on the 20'th, or at 00:00 on the 21st?
*/
patexp_tm.tm_sec = 0;
patexp_tm.tm_min = 0;
patexp_tm.tm_hour = 0;
patexp_tm.tm_mday = 20;
patexp_tm.tm_mon = 8; /* This is Sept., not Aug. */
patexp_tm.tm_year = 100;
exptime = mktime(&patexp_tm);
nowtime = time(NULL);
printf("Today is:\t\t%s", ctime(&nowtime));
printf("RSA patent expires:\t%s", ctime(&exptime));
diff = exptime - nowtime;
days = diff / SECSPERDAY;
printf("There are now %d days left until expiry\n", days);
}
