nextcloud/apps/files_encryption/lib/crypt.php

208 lines
5.7 KiB
PHP
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<?php
/**
* ownCloud
*
* @author Frank Karlitschek
* @copyright 2010 Frank Karlitschek karlitschek@kde.org
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
* License as published by the Free Software Foundation; either
* version 3 of the License, or any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU AFFERO GENERAL PUBLIC LICENSE for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*/
// Todo:
// - Crypt/decrypt button in the userinterface
// - Setting if crypto should be on by default
// - Add a setting "Don´t encrypt files larger than xx because of performance reasons"
// - Transparent decrypt/encrypt in filesystem.php. Autodetect if a file is encrypted (.encrypted extension)
// - Don't use a password directly as encryption key. but a key which is stored on the server and encrypted with the user password. -> password change faster
// - IMPORTANT! Check if the block lenght of the encrypted data stays the same
require_once('Crypt_Blowfish/Blowfish.php');
/**
* This class is for crypting and decrypting
*/
class OC_Crypt {
static private $bf = null;
public static function loginListener($params){
self::init($params['uid'],$params['password']);
}
public static function init($login,$password) {
$view=new OC_FilesystemView('/'.$login);
OC_FileProxy::$enabled=false;
if(!$view->file_exists('/encryption.key')){// does key exist?
OC_Crypt::createkey($login,$password);
}
$key=$view->file_get_contents('/encryption.key');
OC_FileProxy::$enabled=true;
$_SESSION['enckey']=OC_Crypt::decrypt($key, $password);
}
/**
* get the blowfish encryption handeler for a key
* @param string $key (optional)
* @return Crypt_Blowfish
*
* if the key is left out, the default handeler will be used
*/
public static function getBlowfish($key=''){
if($key){
return new Crypt_Blowfish($key);
}else{
if(!isset($_SESSION['enckey'])){
return false;
}
if(!self::$bf){
self::$bf=new Crypt_Blowfish($_SESSION['enckey']);
}
return self::$bf;
}
}
public static function createkey($username,$passcode) {
// generate a random key
$key=mt_rand(10000,99999).mt_rand(10000,99999).mt_rand(10000,99999).mt_rand(10000,99999);
// encrypt the key with the passcode of the user
$enckey=OC_Crypt::encrypt($key,$passcode);
// Write the file
$proxyEnabled=OC_FileProxy::$enabled;
OC_FileProxy::$enabled=false;
$view=new OC_FilesystemView('/'.$username);
$view->file_put_contents('/encryption.key',$enckey);
OC_FileProxy::$enabled=$proxyEnabled;
}
public static function changekeypasscode($oldPassword, $newPassword) {
if(OCP\User::isLoggedIn()){
$username=OCP\USER::getUser();
$view=new OC_FilesystemView('/'.$username);
// read old key
$key=$view->file_get_contents('/encryption.key');
// decrypt key with old passcode
$key=OC_Crypt::decrypt($key, $oldPassword);
// encrypt again with new passcode
$key=OC_Crypt::encrypt($key, $newPassword);
// store the new key
$view->file_put_contents('/encryption.key', $key );
}
}
/**
* @brief encrypts an content
* @param $content the cleartext message you want to encrypt
* @param $key the encryption key (optional)
* @returns encrypted content
*
* This function encrypts an content
*/
public static function encrypt( $content, $key='') {
$bf = self::getBlowfish($key);
return $bf->encrypt($content);
}
/**
* @brief decryption of an content
* @param $content the cleartext message you want to decrypt
* @param $key the encryption key (optional)
* @returns cleartext content
*
* This function decrypts an content
*/
public static function decrypt( $content, $key='') {
$bf = self::getBlowfish($key);
$data=$bf->decrypt($content);
return rtrim($data, "\0");
}
/**
* @brief encryption of a file
* @param string $source
* @param string $target
* @param string $key the decryption key
*
* This function encrypts a file
*/
public static function encryptFile( $source, $target, $key='') {
$handleread = fopen($source, "rb");
if($handleread!=FALSE) {
$handlewrite = fopen($target, "wb");
while (!feof($handleread)) {
$content = fread($handleread, 8192);
$enccontent=OC_CRYPT::encrypt( $content, $key);
fwrite($handlewrite, $enccontent);
}
fclose($handlewrite);
fclose($handleread);
}
}
/**
* @brief decryption of a file
* @param string $source
* @param string $target
* @param string $key the decryption key
*
* This function decrypts a file
*/
public static function decryptFile( $source, $target, $key='') {
$handleread = fopen($source, "rb");
if($handleread!=FALSE) {
$handlewrite = fopen($target, "wb");
while (!feof($handleread)) {
$content = fread($handleread, 8192);
$enccontent=OC_CRYPT::decrypt( $content, $key);
fwrite($handlewrite, $enccontent);
}
fclose($handlewrite);
fclose($handleread);
}
}
/**
* encrypt data in 8192b sized blocks
*/
public static function blockEncrypt($data, $key=''){
$result='';
while(strlen($data)){
$result.=self::encrypt(substr($data,0,8192),$key);
$data=substr($data,8192);
}
return $result;
}
/**
* decrypt data in 8192b sized blocks
*/
public static function blockDecrypt($data, $key=''){
$result='';
while(strlen($data)){
$result.=self::decrypt(substr($data,0,8192),$key);
$data=substr($data,8192);
}
return $result;
}
}