The Encrypt library provides two-way encryption of text and binary strings using the Mcrypt extension, which consists of three parts: the key, the cipher, and the mode.
Class declared in SYSPATH/classes/kohana/encrypt.php on line 26.
string $defaultdefault instance name
string(7) "default"array $instancesEncrypt class instances
array(0) string $_randOS-dependent RAND type to use
NULL
Creates a new mcrypt wrapper.
string
$key
required - Encryption keystring
$mode
required - Mcrypt modestring
$cipher
required - Mcrypt cipherpublic function __construct($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);
}Decrypts an encoded string back to its original value.
$data = $encrypt->decode($data);
string
$data
required - Encoded string to be decryptedFALSE - If decryption failsstringpublic function decode($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");
}Encrypts a string and returns an encrypted string that can be decoded.
$data = $encrypt->encode($data);
The encrypted binary data is encoded using base64 to convert it to a string. This string can be stored in a database, displayed, and passed using most other means without corruption.
string
$data
required - Data to be encryptedstringpublic function encode($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);
}Returns a singleton instance of Encrypt. An encryption key must be provided in your "encrypt" configuration file.
$encrypt = Encrypt::instance();
string
$name
= NULL - Configuration group nameEncryptpublic static function instance($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->load('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];
}