Encrypt
› Kohana_Encrypt

Class Contents

Class declared in SYSPATH/classes/encrypt.php on line 3.

Properties

Methods

public function __construct($key, $mode, $cipher)
{
	// Find the max length of the key, based on cipher and mode
	$size = mcrypt_get_key_size($cipher, $mode);

	if (isset($key[$size]))
	{
		// Shorten the key to the maximum size
		$key = substr($key, 0, $size);
	}

	// Store the key, mode, and cipher
	$this->_key    = $key;
	$this->_mode   = $mode;
	$this->_cipher = $cipher;

	// Store the IV size
	$this->_iv_size = mcrypt_get_iv_size($this->_cipher, $this->_mode);
}

public function decode($data)
{
	// Convert the data back to binary
	$data = base64_decode($data, TRUE);

	if ( ! $data)
	{
		// Invalid base64 data
		return FALSE;
	}

	// Extract the initialization vector from the data
	$iv = substr($data, 0, $this->_iv_size);

	if ($this->_iv_size !== strlen($iv))
	{
		// The iv is not the expected size
		return FALSE;
	}

	// Remove the iv from the data
	$data = substr($data, $this->_iv_size);

	// Return the decrypted data, trimming the \0 padding bytes from the end of the data
	return rtrim(mcrypt_decrypt($this->_cipher, $this->_key, $data, $this->_mode, $iv), "\0");
}

public function encode($data)
{
	// Set the rand type if it has not already been set
	if (Encrypt::$_rand === NULL)
	{
		if (Kohana::$is_windows)
		{
			// Windows only supports the system random number generator
			Encrypt::$_rand = MCRYPT_RAND;
		}
		else
		{
			if (defined('MCRYPT_DEV_URANDOM'))
			{
				// Use /dev/urandom
				Encrypt::$_rand = MCRYPT_DEV_URANDOM;
			}
			elseif (defined('MCRYPT_DEV_RANDOM'))
			{
				// Use /dev/random
				Encrypt::$_rand = MCRYPT_DEV_RANDOM;
			}
			else
			{
				// Use the system random number generator
				Encrypt::$_rand = MCRYPT_RAND;
			}
		}
	}

	if (Encrypt::$_rand === MCRYPT_RAND)
	{
		// The system random number generator must always be seeded each
		// time it is used, or it will not produce true random results
		mt_srand();
	}

	// Create a random initialization vector of the proper size for the current cipher
	$iv = mcrypt_create_iv($this->_iv_size, Encrypt::$_rand);

	// Encrypt the data using the configured options and generated iv
	$data = mcrypt_encrypt($this->_cipher, $this->_key, $data, $this->_mode, $iv);

	// Use base64 encoding to convert to a string
	return base64_encode($iv.$data);
}

public static function instance($name = NULL)
{
	if ($name === NULL)
	{
		// Use the default instance name
		$name = Encrypt::$default;
	}

	if ( ! isset(Encrypt::$instances[$name]))
	{
		// Load the configuration data
		$config = Kohana::config('encrypt')->$name;

		if ( ! isset($config['key']))
		{
			// No default encryption key is provided!
			throw new Kohana_Exception('No encryption key is defined in the encryption configuration group: :group',
				array(':group' => $name));
		}

		if ( ! isset($config['mode']))
		{
			// Add the default mode
			$config['mode'] = MCRYPT_MODE_NOFB;
		}

		if ( ! isset($config['cipher']))
		{
			// Add the default cipher
			$config['cipher'] = MCRYPT_RIJNDAEL_128;
		}

		// Create a new instance
		Encrypt::$instances[$name] = new Encrypt($config['key'], $config['mode'], $config['cipher']);
	}

	return Encrypt::$instances[$name];
}