<code lang="PHP">

        // Generate unique code
	function generateUniqueCode()
	{
		$nRandom = generateRandomNum(1, 50000);
		$nMicro = getMicroTime();
		return ($nRandom + $nMicro);
	}

	// Generate a random number
	function generateRandomNum($Min, $Max)
	{
		mt_srand((double) microtime() * 1000000);
		return mt_rand($Min, $Max);
	}

	// Generates a code string
	function generateCodeString($strKey = "")
	{
		return strtoupper(sha1($strKey . generateUniqueCode()));
	}
</code>