key = $key;
$this->mode = $mode;
$this->cipher = $cipher;
if (trim((string) $this->key) === '')
{
throw new \Exception('The encryption class may not be used without an encryption key.');
}
}
/**
* Encrypt a string using Mcrypt.
*
* The string will be encrypted using the cipher and mode specified when the crypter
* instance was created, and the final result will be base64 encoded.
*
*
* // Encrypt a string using the Mcrypt PHP extension
* $encrypted = Crypter::encrpt('secret');
*
*
* @param string $value
* @return string
*/
public function encrypt($value)
{
// Determine the most appropriate random number generator for the operating
// system and environment the application is running on.
if (defined('MCRYPT_DEV_URANDOM'))
{
$randomizer = MCRYPT_DEV_URANDOM;
}
elseif (defined('MCRYPT_DEV_RANDOM'))
{
$randomizer = MCRYPT_DEV_RANDOM;
}
else
{
$randomizer = MCRYPT_RAND;
}
$iv = mcrypt_create_iv($this->iv_size(), $randomizer);
return base64_encode($iv.mcrypt_encrypt($this->cipher, $this->key, $value, $this->mode, $iv));
}
/**
* Decrypt a string using Mcrypt.
*
* The string will be decrypted using the cipher and mode specified when the crypter was created.
*
*
* // Decrypt a string using the Mcrypt PHP extension
* $decrypted = Crypter::decrypt($secret);
*
*
* @param string $value
* @return string
*/
public function decrypt($value)
{
// Since all encrypted strings generated by this class are base64 encoded, we will
// first attempt to base64 decode the string. If we can't do it, we'll bail out.
if ( ! is_string($value = base64_decode($value, true)))
{
throw new \Exception('Decryption error. Input value is not valid base64 data.');
}
// Extract the input vector and the encrypted string from the value
list($iv, $value) = array(substr($value, 0, $this->iv_size()), substr($value, $this->iv_size()));
return rtrim(mcrypt_decrypt($this->cipher, $this->key, $value, $this->mode, $iv), "\0");
}
/**
* Get the input vector size for the cipher and mode.
*
* Different ciphers and modes use varying lengths of input vectors.
*
* @return int
*/
private function iv_size()
{
return mcrypt_get_iv_size($this->cipher, $this->mode);
}
}