mirror of
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255 lines
8.1 KiB
PHP
255 lines
8.1 KiB
PHP
<?php
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/**
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* Pure-PHP implementation of AES.
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*
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* Uses mcrypt, if available/possible, and an internal implementation, otherwise.
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*
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* PHP version 5
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*
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* NOTE: Since AES.php is (for compatibility and phpseclib-historical reasons) virtually
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* just a wrapper to Rijndael.php you may consider using Rijndael.php instead of
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* to save one include_once().
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*
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* If {@link self::setKeyLength() setKeyLength()} isn't called, it'll be calculated from
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* {@link self::setKey() setKey()}. ie. if the key is 128-bits, the key length will be 128-bits. If it's 136-bits
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* it'll be null-padded to 192-bits and 192 bits will be the key length until {@link self::setKey() setKey()}
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* is called, again, at which point, it'll be recalculated.
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*
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* Since \phpseclib\Crypt\AES extends \phpseclib\Crypt\Rijndael, some functions are available to be called that, in the context of AES, don't
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* make a whole lot of sense. {@link self::setBlockLength() setBlockLength()}, for instance. Calling that function,
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* however possible, won't do anything (AES has a fixed block length whereas Rijndael has a variable one).
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*
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* Here's a short example of how to use this library:
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* <code>
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* <?php
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* include 'vendor/autoload.php';
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*
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* $aes = new \phpseclib\Crypt\AES();
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*
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* $aes->setKey('abcdefghijklmnop');
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*
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* $size = 10 * 1024;
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* $plaintext = '';
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* for ($i = 0; $i < $size; $i++) {
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* $plaintext.= 'a';
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* }
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*
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* echo $aes->decrypt($aes->encrypt($plaintext));
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* ?>
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* </code>
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*
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* @category Crypt
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* @package AES
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* @author Jim Wigginton <terrafrost@php.net>
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* @copyright 2008 Jim Wigginton
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* @license http://www.opensource.org/licenses/mit-license.html MIT License
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* @link http://phpseclib.sourceforge.net
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*/
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namespace phpseclib\Crypt;
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use phpseclib\Common\Functions\Strings;
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/**
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* Pure-PHP implementation of AES.
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*
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* @package AES
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* @author Jim Wigginton <terrafrost@php.net>
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* @access public
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*/
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class AES extends Rijndael
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{
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/**
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* Test for engine validity
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*
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* This is mainly just a wrapper to set things up for \phpseclib\Crypt\Common\SymmetricKey::isValidEngine()
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*
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* @see \phpseclib\Crypt\Common\SymmetricKey::__construct()
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* @param int $engine
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* @access protected
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* @return bool
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*/
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protected function isValidEngineHelper($engine)
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{
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switch ($engine) {
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case self::ENGINE_LIBSODIUM:
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return function_exists('sodium_crypto_aead_aes256gcm_is_available') &&
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sodium_crypto_aead_aes256gcm_is_available() &&
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$this->mode == self::MODE_GCM &&
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$this->key_length == 32 &&
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$this->nonce && strlen($this->nonce) == 12;
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case self::ENGINE_OPENSSL_GCM:
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if (!extension_loaded('openssl')) {
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return false;
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}
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$methods = openssl_get_cipher_methods();
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return $this->mode == self::MODE_GCM &&
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version_compare(PHP_VERSION, '7.1.0', '>=') &&
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in_array('aes-' . $this->getKeyLength() . '-gcm', $methods);
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}
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return parent::isValidEngineHelper($engine);
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}
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/**
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* Dummy function
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*
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* Since \phpseclib\Crypt\AES extends \phpseclib\Crypt\Rijndael, this function is, technically, available, but it doesn't do anything.
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*
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* @see \phpseclib\Crypt\Rijndael::setBlockLength()
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* @access public
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* @param int $length
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* @throws \BadMethodCallException anytime it's called
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*/
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public function setBlockLength($length)
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{
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throw new \BadMethodCallException('The block length cannot be set for AES.');
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}
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/**
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* Sets the key length
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*
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* Valid key lengths are 128, 192, and 256. Set the link to bool(false) to disable a fixed key length
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*
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* @see \phpseclib\Crypt\Rijndael:setKeyLength()
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* @access public
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* @param int $length
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* @throws \LengthException if the key length isn't supported
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*/
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public function setKeyLength($length)
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{
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switch ($length) {
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case 128:
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case 192:
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case 256:
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break;
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default:
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throw new \LengthException('Key of size ' . $length . ' not supported by this algorithm. Only keys of sizes 128, 192 or 256 supported');
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}
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parent::setKeyLength($length);
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}
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/**
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* Sets the key.
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*
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* Rijndael supports five different key lengths, AES only supports three.
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*
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* @see \phpseclib\Crypt\Rijndael:setKey()
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* @see setKeyLength()
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* @access public
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* @param string $key
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* @throws \LengthException if the key length isn't supported
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*/
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public function setKey($key)
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{
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switch (strlen($key)) {
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case 16:
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case 24:
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case 32:
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break;
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default:
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throw new \LengthException('Key of size ' . strlen($key) . ' not supported by this algorithm. Only keys of sizes 16, 24 or 32 supported');
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}
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parent::setKey($key);
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}
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/**
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* Encrypts a message.
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*
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* @see self::decrypt()
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* @see parent::encrypt()
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* @access public
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* @param string $plaintext
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* @return string
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*/
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public function encrypt($plaintext)
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{
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switch ($this->engine) {
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case self::ENGINE_LIBSODIUM:
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$this->checkForChanges();
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$this->newtag = sodium_crypto_aead_aes256gcm_encrypt($plaintext, $this->aad, $this->nonce, $this->key);
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return Strings::shift($this->newtag, strlen($plaintext));
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case self::ENGINE_OPENSSL_GCM:
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$this->checkForChanges();
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return openssl_encrypt(
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$plaintext,
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'aes-' . $this->getKeyLength() . '-gcm',
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$this->key,
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OPENSSL_RAW_DATA,
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$this->nonce,
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$this->newtag,
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$this->aad
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);
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}
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return parent::encrypt($plaintext);
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}
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/**
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* Decrypts a message.
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*
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* @see self::encrypt()
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* @see parent::decrypt()
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* @access public
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* @param string $ciphertext
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* @return string
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*/
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public function decrypt($ciphertext)
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{
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switch ($this->engine) {
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case self::ENGINE_LIBSODIUM:
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$this->checkForChanges();
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if ($this->oldtag === false) {
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throw new \UnexpectedValueException('Authentication Tag has not been set');
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}
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if (strlen($this->oldtag) != 16) {
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break;
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}
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$plaintext = sodium_crypto_aead_aes256gcm_decrypt($ciphertext . $this->oldtag, $this->aad, $this->nonce, $this->key);
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if ($plaintext === false) {
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$this->oldtag = false;
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throw new \UnexpectedValueException('Error decrypting ciphertext with libsodium');
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}
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return $plaintext;
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case self::ENGINE_OPENSSL_GCM:
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$this->checkForChanges();
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if ($this->oldtag === false) {
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throw new \UnexpectedValueException('Authentication Tag has not been set');
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}
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$plaintext = openssl_decrypt(
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$ciphertext,
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'aes-' . $this->getKeyLength() . '-gcm',
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$this->key,
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OPENSSL_RAW_DATA,
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$this->nonce,
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$this->oldtag,
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$this->aad
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);
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if ($plaintext === false) {
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$this->oldtag = false;
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throw new \UnexpectedValueException('Error decrypting ciphertext with OpenSSL');
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}
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return $plaintext;
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}
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return parent::decrypt($ciphertext);
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}
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/**
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* Check For Changes
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*
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* @see self::encrypt()
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* @see self::decrypt()
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* @access private
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*/
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private function checkForChanges()
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{
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if ($this->changed) {
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$this->clearBuffers();
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$this->changed = false;
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}
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}
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}
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