/**
* Fetch the plain encryption key for the file and set it as plainKey property
* @internal param bool $generate if true, a new key will be generated if none can be found
* @return bool true on key found and set, false on key not found and new key generated and set
*/
public function getKey()
{
// Check if key is already set
if (isset($this->plainKey) && isset($this->encKeyfile)) {
return true;
}
$util = new Util($this->rootView, $this->userId);
// Fetch and decrypt keyfile
// Fetch existing keyfile
$this->encKeyfile = Keymanager::getFileKey($this->rootView, $util, $this->relPath);
// If a keyfile already exists
if ($this->encKeyfile) {
$shareKey = Keymanager::getShareKey($this->rootView, $this->keyId, $util, $this->relPath);
// if there is no valid private key return false
if ($this->privateKey === false) {
// if private key is not valid redirect user to a error page
Helper::redirectToErrorPage($this->session);
return false;
}
if ($shareKey === false) {
// if no share key is available redirect user to a error page
Helper::redirectToErrorPage($this->session, Crypt::ENCRYPTION_NO_SHARE_KEY_FOUND);
return false;
}
$this->plainKey = Crypt::multiKeyDecrypt($this->encKeyfile, $shareKey, $this->privateKey);
return true;
} else {
$this->newFile = true;
return false;
}
}
/**
* decrypt given file with recovery key and encrypt it again to the owner and his new key
* @param string $file
* @param string $privateKey recovery key to decrypt the file
*/
private function recoverFile($file, $privateKey)
{
$sharingEnabled = \OCP\Share::isEnabled();
// Find out who, if anyone, is sharing the file
if ($sharingEnabled) {
$result = \OCP\Share::getUsersSharingFile($file, $this->userId, true);
$userIds = $result['users'];
$userIds[] = $this->recoveryKeyId;
if ($result['public']) {
$userIds[] = $this->publicShareKeyId;
}
} else {
$userIds = array($this->userId, $this->recoveryKeyId);
}
$filteredUids = $this->filterShareReadyUsers($userIds);
//decrypt file key
$encKeyfile = Keymanager::getFileKey($this->view, $this, $file);
$shareKey = Keymanager::getShareKey($this->view, $this->recoveryKeyId, $this, $file);
$plainKeyfile = Crypt::multiKeyDecrypt($encKeyfile, $shareKey, $privateKey);
// encrypt file key again to all users, this time with the new public key for the recovered use
$userPubKeys = Keymanager::getPublicKeys($this->view, $filteredUids['ready']);
$multiEncKey = Crypt::multiKeyEncrypt($plainKeyfile, $userPubKeys);
Keymanager::setFileKey($this->view, $this, $file, $multiEncKey['data']);
Keymanager::setShareKeys($this->view, $this, $file, $multiEncKey['keys']);
}
/**
* @large
*/
public function testMultiKeyEncrypt()
{
# TODO: search in keyfile for actual content as IV will ensure this test always passes
$pair1 = \OCA\Files_Encryption\Crypt::createKeypair();
$this->assertEquals(2, count($pair1));
$this->assertTrue(strlen($pair1['publicKey']) > 1);
$this->assertTrue(strlen($pair1['privateKey']) > 1);
$crypted = \OCA\Files_Encryption\Crypt::multiKeyEncrypt($this->dataShort, array($pair1['publicKey']));
$this->assertNotEquals($this->dataShort, $crypted['data']);
$decrypt = \OCA\Files_Encryption\Crypt::multiKeyDecrypt($crypted['data'], $crypted['keys'][0], $pair1['privateKey']);
$this->assertEquals($this->dataShort, $decrypt);
}