/**
* Test for engine validity
*
* This is mainly just a wrapper to set things up for \phpseclib\Crypt\Base::isValidEngine()
*
* @see \phpseclib\Crypt\Base::isValidEngine()
* @param int $engine
* @access public
* @return bool
*/
function isValidEngine($engine)
{
if ($engine == self::ENGINE_OPENSSL) {
if ($this->key_length != 16) {
return false;
}
$this->cipher_name_openssl_ecb = 'bf-ecb';
$this->cipher_name_openssl = 'bf-' . $this->_openssl_translate_mode();
}
return parent::isValidEngine($engine);
}
/**
* Sets the key.
*
* Keys can be of any length. Twofish, itself, requires the use of a key that's 128, 192 or 256-bits long.
* If the key is less than 256-bits we round the length up to the closest valid key length,
* padding $key with null bytes. If the key is more than 256-bits, we trim the excess bits.
*
* If the key is not explicitly set, it'll be assumed a 128 bits key to be all null bytes.
*
* @access public
* @see \phpseclib\Crypt\Base::setKey()
* @param String $key
*/
function setKey($key)
{
$keylength = strlen($key);
switch (true) {
case $keylength <= 16:
$key = str_pad($key, 16, "");
break;
case $keylength <= 24:
$key = str_pad($key, 24, "");
break;
case $keylength < 32:
$key = str_pad($key, 32, "");
break;
case $keylength > 32:
$key = substr($key, 0, 32);
}
parent::setKey($key);
}
/**
* Decrypts a message.
*
* $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)).
* At least if the continuous buffer is disabled.
*
* @see \phpseclib\Crypt\Base::encrypt()
* @see \phpseclib\Crypt\RC4::_crypt()
* @access public
* @param String $ciphertext
* @return String $plaintext
*/
function decrypt($ciphertext)
{
if ($this->engine != Base::ENGINE_INTERNAL) {
return parent::decrypt($ciphertext);
}
return $this->_crypt($ciphertext, self::DECRYPT);
}
/**
* Setup the \phpseclib\Crypt\Base::ENGINE_MCRYPT $engine
*
* @see \phpseclib\Crypt\Base::_setupMcrypt()
* @access private
*/
function _setupMcrypt()
{
if (!isset($this->key)) {
$this->setKey('');
}
parent::_setupMcrypt();
}
/**
* This function deinitializes an encryption module
*
* This function terminates encryption specified by the encryption descriptor (td).
* It clears all buffers, but does not close the module. You need to call
* mcrypt_module_close() yourself. (But PHP does this for you at the end of the
* script.)
*
* @param \phpseclib\Crypt\Base $td
* @return bool
* @access public
*/
function phpseclib_mcrypt_generic_deinit(Base $td)
{
if (!isset($td->mcrypt_polyfill_init)) {
trigger_error('mcrypt_generic_deinit(): Could not terminate encryption specifier', E_USER_WARNING);
return false;
}
$td->disableContinuousBuffer();
unset($td->mcrypt_polyfill_init);
return true;
}
/**
* Setup the \phpseclib\Crypt\Base::ENGINE_MCRYPT $engine
*
* @see \phpseclib\Crypt\Base::_setupMcrypt()
* @access private
*/
function _setupMcrypt()
{
$this->key = str_pad(substr($this->key, 0, $this->key_size), $this->key_size, "");
parent::_setupMcrypt();
}
/**
* Test for engine validity
*
* This is mainly just a wrapper to set things up for \phpseclib\Crypt\Base::isValidEngine()
*
* @see \phpseclib\Crypt\Base::__construct()
* @param int $engine
* @access public
* @return bool
*/
function isValidEngine($engine)
{
switch ($engine) {
case self::ENGINE_OPENSSL:
if ($this->block_size != 16) {
return false;
}
$this->cipher_name_openssl_ecb = 'aes-' . ($this->key_length << 3) . '-ecb';
$this->cipher_name_openssl = 'aes-' . ($this->key_length << 3) . '-' . $this->_openssl_translate_mode();
break;
case self::ENGINE_MCRYPT:
$this->cipher_name_mcrypt = 'rijndael-' . ($this->block_size << 3);
if ($this->key_length % 8) {
// is it a 160/224-bit key?
// mcrypt is not usable for them, only for 128/192/256-bit keys
return false;
}
}
return parent::isValidEngine($engine);
}
/**
* Sets the key.
*
* Keys can be of any length. DES, itself, uses 64-bit keys (eg. strlen($key) == 8), however, we
* only use the first eight, if $key has more then eight characters in it, and pad $key with the
* null byte if it is less then eight characters long.
*
* DES also requires that every eighth bit be a parity bit, however, we'll ignore that.
*
* If the key is not explicitly set, it'll be assumed to be all zero's.
*
* @see \phpseclib\Crypt\Base::setKey()
* @access public
* @param string $key
*/
function setKey($key)
{
// We check/cut here only up to max length of the key.
// Key padding to the proper length will be done in _setupKey()
if (strlen($key) > $this->key_size_max) {
$key = substr($key, 0, $this->key_size_max);
}
// Sets the key
parent::setKey($key);
}
/**
* Sets the key length.
*
* Valid key lengths are 128, 192 or 256 bits
*
* @access public
* @param int $length
*/
function setKeyLength($length)
{
switch (true) {
case $length <= 128:
$this->key_length = 16;
break;
case $length <= 192:
$this->key_length = 24;
break;
default:
$this->key_length = 32;
}
parent::setKeyLength($length);
}
