Vergleich inc/functions.php - 1.4.11 - 1.4.12

}

/**
 * Returns a securely generated seed for PHP's RNG (Random Number Generator)
 *
 * @param int Length of the seed bytes (8 is default. Provides good cryptographic variance)
 * @return int An integer equivilent of a secure hexadecimal seed
 */
function secure_seed_rng($count=8)
{
	$output = '';
		
	// Try the OpenSSL method first. This is the strongest.
	if(function_exists('openssl_random_pseudo_bytes'))
	{
		$output = openssl_random_pseudo_bytes($count, $strong);
		
		if($strong !== true)
		{
			$output = '';
		}
	}
	
	if($output == '')
	{
		// Then try the unix/linux method
		if(@is_readable('/dev/urandom') && ($handle = @fopen('/dev/urandom', 'rb')))
		{
			$output = @fread($handle, $count);
			@fclose($handle);
		}
	}
	
	// Didn't work? Do we still not have enough bytes? Use our own (less secure) rng generator
	if(strlen($output) < $count)
	{
		$output = '';
		
		// Close to what PHP basically uses internally to seed, but not quite.
		$unique_state = microtime().@getmypid();
		
		for($i = 0; $i < $count; $i += 16)
		{
			$unique_state = md5(microtime().$unique_state);
			$output .= pack('H*', md5($unique_state));
		}
	}
	
	// /dev/urandom and openssl will always be twice as long as $count. base64_encode will roughly take up 33% more space but crc32 will put it to 32 characters
	$output = hexdec(substr(dechex(crc32(base64_encode($output))), 0, $count));
	
	return $output;
}

/**
 * Wrapper function for mt_rand. Automatically seeds using a secure seed once.
 *
 * @param int Optional lowest value to be returned (default: 0) 
 * @param int Optional highest value to be returned (default: mt_getrandmax()) 
 * @param boolean True forces it to reseed the RNG first
 * @return int An integer equivilent of a secure hexadecimal seed
 */
function my_rand($min=null, $max=null, $force_seed=false)
{
	static $seeded = false;
	
	if($seeded == false || $force_seed == true)
	{
		mt_srand(secure_seed_rng());
		$seeded = true;
	}
	
	if($min !== null && $max !== null)
	{
		return mt_rand($min, $max);
	}
	else
	{
		return mt_rand();
	}