FastSpring License Generator (PHP)

<?php
    $tokens = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
    $segment_chars = 5;
    $num_segments = 4;
    $key_string = '';

    for ($i = 0; $i < $num_segments; $i++) {
        $segment = '';

        for ($j = 0; $j < $segment_chars; $j++) {
            $segment .= $tokens[rand(0, 35)];
        }

        $key_string .= $segment;

        if ($i < ($num_segments - 1)) {
            $key_string .= '-';
        }
    }

	echo $key_string;
?>