Re: a challenge

[Andrew Perrin <aperrin@email.unc.edu>]

What about using crypt() and the timestamp? Something like:

#!/usr/local/bin/perl -w

use strict;

my $time = time;
my $salt = 'md'; #mad duck

$time = join('',reverse(split('',$time))); #reverse time because
crypt() only
                                           # deals w/ first 8 chars

print "Localtime: $time\n";
print crypt($time,$salt), "\n";

exit 0;

Just an idea...
ap

----------------------------------------------------------------------
Andrew J Perrin - andrew_perrin@unc.edu - http://www.unc.edu/~aperrin
 Assistant Professor of Sociology, U of North Carolina, Chapel Hill
      269 Hamilton Hall, CB#3210, Chapel Hill, NC 27599-3210 USA


On Thu, 18 Oct 2001, martin f krafft wrote:

> goal: a 4-16 byte 7-bit character value that somehow encodes the time
>   of creation such that it can be extracted if the encoding scheme/seed
>   is known. the encoded value should be such that it is mostly
>   impossible to change it so as to yield a later time of creation to be
>   encoded. in general, changing the encoded value may well render the
>   data invalid.
> 
>   this is supposed to be a token that's valid for a limited amount of
>   time, after which, a new token has to be fetched. this token should
>   not be obvious (e.g. the timestamp) to prevent people from changing
>   it to be valid longer rather than fetching a new one.
> 
> can you do it? or is there a tool out there?
> 
> -- 
> martin;              (greetings from the heart of the sun.)
>   \____ echo mailto: !#^."<*>"|tr "<*> mailto:"; net@madduck
>   
> echo '[dO%O+38%O+PO/d0<0]Fi22os0CC4BA64E418CE7l0xAP'|dc
>