public function testDiceware($numWords = 3)
    {
        $wordlistUrl = 'https://www.eff.org/files/2016/07/18/eff_large_wordlist.txt';

        if (!file_exists(CACHE_DIR . '/' . basename($wordlistUrl))) {
            $wordlist = file_get_contents($wordlistUrl);
            file_put_contents(CACHE_DIR . '/' . basename($wordlistUrl), $wordlist);
        } else {
            $wordlist = file_get_contents(CACHE_DIR . '/' . basename($wordlistUrl));
        }

        $dies = 5;
        $words = [];

        for ($n = 0; $n < $numWords; $n++) {

            $rolls = [];

            for ($i = $dies; $i > 0; $i--) {
                $rolls[] = rand(1, 6);
            }

            $key = implode('', $rolls);

            preg_match('#^' . $key . '\s+(.*?)$#sm', $wordlist, $matches);
            $words[] = $matches[1];
        }

        $phrase = str_replace(' ', '', lcfirst(ucwords(implode(' ', $words))));

        return $phrase;
    }