use Digest::MD4 md4_hex;
 
my $goal = '8c91a67ef3a47031ec08830327848826'; # hash to find
my @chars = ( a..z, 0..9 ); # characters to use
my $minlen = 1; # minimum length of string
my $maxlen = 8; # maximum length of string
 
for ( $minlen..$maxlen ) {
	print 'Length: ', $_, "\n";
	&checkStrings($_);
}
 
sub checkStrings {
	my ( $n, $s ) = ( (shift) - 1, shift );
	for ( @chars ) {
		if ( $n ) {
			checkStrings($n, $s . $_ );
		} else {
			print $s, $_, "\n" if md4_hex( $s . $_ ) eq $goal;
		}
	}
}