public static function v5(string $namespace, string $name)
    {
        if (!Validate::isValidUUID($namespace)) {
            return false;
        }

        // Get hexadecimal components of namespace
        $nhex = str_replace(array('-', '{', '}'), '', $namespace);

        // Binary Value
        $nstr = '';

        // Convert Namespace UUID to bits
        for ($i = 0; $i < strlen($nhex); $i += 2) {
            $nstr .= \chr(hexdec($nhex[$i] . $nhex[$i + 1]));
        }

        // Calculate hash value
        $hash = sha1($nstr . $name);

        return sprintf('%08s-%04s-%04x-%04x-%12s',

            // 32 bits for "time_low"
            substr($hash, 0, 8),

            // 16 bits for "time_mid"
            substr($hash, 8, 4),

            // 16 bits for "time_hi_and_version",
            // four most significant bits holds version number 5
            (hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x5000,

            // 16 bits, 8 bits for "clk_seq_hi_res",
            // 8 bits for "clk_seq_low",
            // two most significant bits holds zero and one for variant DCE1.1
            (hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,

            // 48 bits for "node"
            substr($hash, 20, 12)
        );
    }