Genuine Quantum Randomness

[John M. Dlugosz]

Well, I think it's pretty cool, but I've always liked physics. Chaotic systems are just like pseudorandom numbers only you don't know the seed. But quantum processes can be genuinly random and fundimentally unpredictable.

Fourmilab, where atom-smashing geeks dwell, has a cute toy in the basement. It generates true random numbers based on radioactive decay, and makes data available to the public.

They have a Java package to programmatically access it, but I wanted to do it in Perl. So I wrote a simple Perl module to access the server. I don't know how useful this is for most folks, but hey, it's cool!

—John
(code follows)

sample program

use strict;
use warnings;
use HotBits;

my $x= new HotBits::;
my $bits= $x->request (16);  # parameter is bytes to fetch, up to 2048
+.
print length($bits)," bytes: ";
print unpack("H*", $bits), "\n";

HotBits.pm

=head1 NAME B<HotBits> - download hardware random numbers

=head1 AUTHOR  John M. Dlugosz - [e-mail] - http://www.dlugosz
+.com

=head1 DESCRIPTION

This module will access "genuine" random numbers via http://www.fourmi
+lab.ch/hotbits/.
This server at Fourmilab in Switzerland uses radioactive decay to offe
+r the truest random
number source possible.  This module works the same as the site's Java
+ class for the same
purpose: access the CGI program via HTTP.

=cut

package HotBits;

use strict;
use warnings;
our $VERSION= v1.0;
require LWP::UserAgent;
use Carp;

my $serverURL='http://www.fourmilab.ch/cgi-bin/uncgi/Hotbits';

sub new
 {
 my $class= shift;
 my $URL= shift || $serverURL;  # optional argument
 my $ua = new LWP::UserAgent::;
 $ua->env_proxy();
 my $self= bless {
    ua => $ua,
    URL => $URL
    }, $class;
 return $self;
 }

sub request
 {
 my ($self, $count)= @_;
 $count ||= 128;
 my $request = HTTP::Request->new('GET', "$self->{URL}?nbytes=$count&f
+mt=bin");
 $request->proxy_authorization_basic($ENV{HTTP_proxy_user}, $ENV{HTTP_
+proxy_pass})  if $ENV{HTTP_proxy_user};
 my $response = $self->{ua}->request($request);
 croak "Error from $self->{URL}", if ($response->code() != 200);
 croak "Unexpected return (not binary) from $self->{URL}" if $response
+->headers()->content_type() ne "application/octet-stream";
 return $response->content();
 }

1; # module loaded OK.

[dws]

For another random number generator based on a chaotic system (lava lamps), see http://lavarand.sgi.com/.

This wins points in my book for one of the coolest applications of lava lamp technology.

Update: They're defunct. Poo.

[John M. Dlugosz]

I looked at lavaland just the other day, and it seems to be defunct. No updates in a couple years, and plans for stuff that may get done during 2000. Can't get any freshly generated random data from them.

If I were to build something, I think a radio tuned to no station, patched to the mic input on a sound card would be a good and cheap chaos sampler.

How does the random number generator in Perl's rand work? It seems pretty good, and I remember years ago reading that they no longer use the C library's generator.

—John

[d4vis]

From the perldelta for v5.6.0:

Better pseudo-random number generator
In 5.005_0x and earlier, perl's rand() function used the C library rand(3) function. As of 5.005_52, Configure tests for drand48(), random(), and rand() (in that order) and picks the first one it finds.

These changes should result in better random numbers from rand().

~monk d4vis
#!/usr/bin/fnord

[knobunc]

Also check out www.random.org.

-ben