# -- csrand.pl - cryptographically secure random number generator
# -- For some reason the CAPICOM_ENCODE_BINARY option doesn't work in the Activestate Win32 perl 5.8 implementation
# -- so I used CAPICOM_ENCODE_BASE64 and decoded that for the random number.
use Win32::OLE;
Win32::OLE->Option(Warn => 3);

# get CAPICOM VarType CONSTANTS from  Capicom.dll, commented out - takes too long searching registry sometimes
#use Win32::OLE::Const 'CAPICOM v2.1 Type Library';
# --- use the constants below instead , thats all we need - get values from object browser  
$CAPICOM_ENCODE_ANY = -1;
$CAPICOM_ENCODE_BASE64 = 0;
$CAPICOM_ENCODE_BINARY = 1;

my $RNG = Win32::OLE->new("CAPICOM.Utilities");  # download Capicom.dll from Microsoft.com

my $die1 = 255; 
my $die2 = 255;
#--- for uniform distribution of die faces: 6 divides 252  252 = 251+1(includes zero)
while ($die1 > 251){ # reject if true - get another random number, must be divisible by 6 for uniformity
 $die1 = $RNG->GetRandom({Length => 1 , EncodingType => $CAPICOM_ENCODE_BASE64}); # get one byte of random bits
 $die1 = unpack "C", DECODEBASE64($die1);
}
while ($die2 > 251){ # reject if true - get another random number, must be divisible by 6 for uniformity
 $die2 = $RNG->GetRandom({Length => 1 , EncodingType => $CAPICOM_ENCODE_BASE64}); # get one byte of random bits
 $die2 = unpack "C", DECODEBASE64("$die2");
}

# --- the usual modulo 6 + 1 on an integer
print "You rolled ",$die1 % 6 + 1, ",",$die2 % 6 +1 ,"\n";

sub DECODEBASE64{  # see Programming Perl 2nd edition
my $die = $_[0];
$die =~ tr|A-Za-z0-9+/||cd;
$die =~ tr|A-Za-z0-9+/| -_|;
$die = unpack("u",pack("c", 32+(length $die)* .75) . $die);
return $die;
}