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<?php |
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|
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/** |
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* This class provides the functionality to encrypt |
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* and decrypt access tokens stored by the application |
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* @author Ben Tadiar <ben@handcraftedbyben.co.uk> |
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* @link https://github.com/benthedesigner/dropbox |
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* @package Dropbox\Oauth |
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* @subpackage Storage |
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*/ |
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|
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class Dropbox_Encrypter |
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{ |
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// Encryption settings - default settings yield encryption to AES (256-bit) standard |
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// @todo Provide PHPDOC for each class constant |
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const KEY_SIZE = 32; |
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const IV_SIZE = 16; |
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|
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/** |
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* Encryption key |
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* @var null|string |
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*/ |
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private $key = null; |
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|
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/** |
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* Check Mcrypt is loaded and set the encryption key |
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* @param string $key |
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* @return void |
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*/ |
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public function __construct($key) |
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{ |
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if (preg_match('/^[A-Za-z0-9]+$/', $key) && $length = strlen($key) === self::KEY_SIZE) { |
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# Short-cut so that the mbstring extension is not required |
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$this->key = $key; |
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} elseif (($length = mb_strlen($key, '8bit')) !== self::KEY_SIZE) { |
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throw new Dropbox_Exception('Expecting a ' . self::KEY_SIZE . ' byte key, got ' . $length); |
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} else { |
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// Set the encryption key |
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$this->key = $key; |
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} |
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} |
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|
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/** |
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* Encrypt the OAuth token |
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* @param \stdClass $token Serialized token object |
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* @return string |
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*/ |
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public function encrypt($token) |
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{ |
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|
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// Encryption: we always use phpseclib for this |
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global $iwp_backup_core; |
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$ensure_phpseclib = $iwp_backup_core->ensure_phpseclib('Crypt_AES'); |
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|
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if (is_wp_error($ensure_phpseclib)) { |
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$iwp_backup_core->log("Failed to load phpseclib classes (".$ensure_phpseclib->get_error_code()."): ".$ensure_phpseclib->get_error_message()); |
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$iwp_backup_core->log("Failed to load phpseclib classes (".$ensure_phpseclib->get_error_code()."): ".$ensure_phpseclib->get_error_message(), 'error'); |
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return false; |
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} |
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|
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$iwp_backup_core->ensure_phpseclib('Crypt_Rijndael'); |
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|
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if (!function_exists('crypt_random_string')) require_once($GLOBALS['iwp_mmb_plugin_dir'].'/lib/phpseclib/phpseclib/phpseclib/Crypt/Random.php'); |
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|
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$iv = crypt_random_string(self::IV_SIZE); |
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|
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// Defaults to CBC mode |
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$rijndael = new Crypt_Rijndael(); |
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|
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$rijndael->setKey($this->key); |
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|
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$rijndael->setIV($iv); |
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|
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$cipherText = $rijndael->encrypt($token); |
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|
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return base64_encode($iv . $cipherText); |
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} |
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|
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/** |
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* Decrypt the ciphertext |
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* @param string $cipherText |
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* @return object \stdClass Unserialized token |
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*/ |
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public function decrypt($cipherText) |
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{ |
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|
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// Decryption: prefer mcrypt, if available (since it can decrypt data encrypted by either mcrypt or phpseclib) |
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|
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$cipherText = base64_decode($cipherText); |
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$iv = substr($cipherText, 0, self::IV_SIZE); |
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$cipherText = substr($cipherText, self::IV_SIZE); |
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|
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if (function_exists('mcrypt_decrypt')) { |
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// @codingStandardsIgnoreLine |
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$token = @mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $this->key, $cipherText, MCRYPT_MODE_CBC, $iv); |
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} else { |
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global $iwp_backup_core; |
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$iwp_backup_core->ensure_phpseclib('Crypt_Rijndael'); |
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|
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$rijndael = new Crypt_Rijndael(); |
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$rijndael->setKey($this->key); |
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$rijndael->setIV($iv); |
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$token = $rijndael->decrypt($cipherText); |
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} |
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|
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return $token; |
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} |
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} |
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|
