public static function generate_uuid() {
		return sprintf( '%04x%04x-%04x-%04x-%04x-%04x%04x%04x', // 32 bits for "time_low"
			mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ),

			// 16 bits for "time_mid"
			mt_rand( 0, 0xffff ),

			// 16 bits for "time_hi_and_version",
			// four most significant bits holds version number 4
			mt_rand( 0, 0x0fff ) | 0x4000,

			// 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
			mt_rand( 0, 0x3fff ) | 0x8000,

			// 48 bits for "node"
			mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ) );
	}