wordpress/php-fpm/wordpress_files/plugins/backwpup/inc/class-encryption-openssl.php

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2020-05-22 03:40:23 +02:00
<?php
/**
* Encrypt / decrypt data using Open SSL.
*
* This is the method used with PHP 5.3+ and open SSL lib available.
*
* Normally we should implement an interface, but at the moment with PHP 5.2 and the "poor" autoloader we have,
* an interface would just be another file in "/inc" folder causing confusion. Also, I don't want to create an
* interface in a file named `class-...php`. When we get rid of PHP 5.2, we setup a better autoloader and we get rid of
* WP coding standard, we finally could consider to introduce an interface.
*/
class BackWPup_Encryption_OpenSSL {
/**
* Prefix
*
* @var string
*/
const PREFIX = 'OSSL$';
/**
* Cipher Method
*
* @var string
*/
private static $cipher_method;
private $key;
private $key_type;
/**
* Supported
*
* @return bool
*/
public static function supported() {
return
function_exists( 'openssl_get_cipher_methods' )
&& self::cipher_method();
}
/**
* BackWPup_Encryption_OpenSSL constructor
*
* @param string $enc_key
* @param string $key_type
*/
public function __construct($enc_key, $key_type)
{
$this->key = md5((string)$enc_key);
$this->key_type = (string)$key_type;
}
/**
* Encrypt a string using Open SSL lib with AES-256-CTR cypher
*
* @param string $string value to encrypt.
*
* @return string encrypted string
*/
public function encrypt($string)
{
if (!is_string($string) || !$string) {
return '';
}
$nonce = openssl_random_pseudo_bytes(openssl_cipher_iv_length(self::cipher_method()));
$openssl_raw_data = defined('OPENSSL_RAW_DATA') ? OPENSSL_RAW_DATA : 1;
$encrypted = openssl_encrypt(
$string,
self::cipher_method(),
$this->key,
$openssl_raw_data,
$nonce
);
return BackWPup_Encryption::PREFIX . self::PREFIX . $this->key_type . base64_encode($nonce . $encrypted);
}
/**
* Decrypt a string using Open SSL lib with AES-256-CTR cypher
*
* @param string $string value to decrypt.
*
* @return string decrypted string
*/
public function decrypt($string)
{
if (
!is_string($string)
|| !$string
|| strpos($string, BackWPup_Encryption::PREFIX . self::PREFIX . $this->key_type) !== 0
) {
return '';
}
$no_prefix = substr($string,
strlen(BackWPup_Encryption::PREFIX . self::PREFIX . $this->key_type));
$encrypted = base64_decode($no_prefix, true);
if ($encrypted === false) {
return '';
}
$nonce_size = openssl_cipher_iv_length(self::cipher_method());
$nonce = substr($encrypted, 0, $nonce_size);
$to_decrypt = substr($encrypted, $nonce_size);
$openssl_raw_data = defined('OPENSSL_RAW_DATA') ? OPENSSL_RAW_DATA : true;
$decrypted = openssl_decrypt(
$to_decrypt,
self::cipher_method(),
$this->key,
$openssl_raw_data,
$nonce
);
return $decrypted;
}
/**
* Cipher Method
*
* @return string
*/
private static function cipher_method() {
if ( is_string( self::$cipher_method ) ) {
return self::$cipher_method;
}
$all_methods = openssl_get_cipher_methods();
if ( ! $all_methods ) {
self::$cipher_method = '';
return '';
}
$preferred = array( 'AES-256-CTR', 'AES-128-CTR', 'AES-192-CTR' );
foreach ( $preferred as $method ) {
if ( in_array( $method, $all_methods, true ) ) {
self::$cipher_method = $method;
return $method;
}
}
self::$cipher_method = reset( $all_methods );
return self::$cipher_method;
}
}