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<?php
/**
* ownCloud
*
* @author Frank Karlitschek
* @copyright 2012 Frank Karlitschek frank@owncloud.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) {
$view=new OC_FilesystemView('/');
if(!$view->file_exists('/'.$login)) {
$view->mkdir('/'.$login);
}
OC_FileProxy::$enabled=false;
if(!$view->file_exists('/'.$login.'/encryption.key')) {// does key exist?
OC_Crypt::createkey($login, $password);
}
$key=$view->file_get_contents('/'.$login.'/encryption.key');
OC_FileProxy::$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 $data;
}
/**
* @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, $key);
if(feof($handleread)) {
$enccontent=rtrim($enccontent, "\0");
}
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='', $maxLength=0) {
$result='';
while(strlen($data)) {
$result.=self::decrypt(substr($data, 0, 8192), $key);
$data=substr($data, 8192);
}
if($maxLength>0) {
return substr($result, 0, $maxLength);
}else{
return rtrim($result, "\0");
}
}
}
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