/**
* start receiving chunks from a file. This is the place where you can
* perform some initial step before starting encrypting/decrypting the
* chunks
*
* @param string $path to the file
* @param string $user who read/write the file
* @param string $mode php stream open mode
* @param array $header contains the header data read from the file
* @param array $accessList who has access to the file contains the key 'users' and 'public'
*
* @return array $header contain data as key-value pairs which should be
* written to the header, in case of a write operation
* or if no additional data is needed return a empty array
*/
public function begin($path, $user, $mode, array $header, array $accessList)
{
$this->path = $this->getPathToRealFile($path);
$this->accessList = $accessList;
$this->user = $user;
$this->isWriteOperation = false;
$this->writeCache = '';
$this->fileKey = $this->keyManager->getFileKey($this->path, $this->user);
if ($mode === 'w' || $mode === 'w+' || $mode === 'wb' || $mode === 'wb+') {
$this->isWriteOperation = true;
if (empty($this->fileKey)) {
$this->fileKey = $this->crypt->generateFileKey();
}
}
if (isset($header['cipher'])) {
$this->cipher = $header['cipher'];
} elseif ($this->isWriteOperation) {
$this->cipher = $this->crypt->getCipher();
} else {
// if we read a file without a header we fall-back to the legacy cipher
// which was used in <=oC6
$this->cipher = $this->crypt->getLegacyCipher();
}
return array('cipher' => $this->cipher);
}
/**
* encrypt data
*
* @param string $data you want to encrypt
* @return mixed encrypted data
*/
public function encrypt($data)
{
$this->isWriteOperation = true;
if (empty($this->fileKey)) {
$this->fileKey = $this->crypt->generateFileKey();
}
// If extra data is left over from the last round, make sure it
// is integrated into the next 6126 / 8192 block
if ($this->writeCache) {
// Concat writeCache to start of $data
$data = $this->writeCache . $data;
// Clear the write cache, ready for reuse - it has been
// flushed and its old contents processed
$this->writeCache = '';
}
$encrypted = '';
// While there still remains some data to be processed & written
while (strlen($data) > 0) {
// Remaining length for this iteration, not of the
// entire file (may be greater than 8192 bytes)
$remainingLength = strlen($data);
// If data remaining to be written is less than the
// size of 1 6126 byte block
if ($remainingLength < 6126) {
// Set writeCache to contents of $data
// The writeCache will be carried over to the
// next write round, and added to the start of
// $data to ensure that written blocks are
// always the correct length. If there is still
// data in writeCache after the writing round
// has finished, then the data will be written
// to disk by $this->flush().
$this->writeCache = $data;
// Clear $data ready for next round
$data = '';
} else {
// Read the chunk from the start of $data
$chunk = substr($data, 0, 6126);
$encrypted .= $this->crypt->symmetricEncryptFileContent($chunk, $this->fileKey);
// Remove the chunk we just processed from
// $data, leaving only unprocessed data in $data
// var, for handling on the next round
$data = substr($data, 6126);
}
}
return $encrypted;
}
/**
* start receiving chunks from a file. This is the place where you can
* perform some initial step before starting encrypting/decrypting the
* chunks
*
* @param string $path to the file
* @param string $user who read/write the file
* @param string $mode php stream open mode
* @param array $header contains the header data read from the file
* @param array $accessList who has access to the file contains the key 'users' and 'public'
*
* @return array $header contain data as key-value pairs which should be
* written to the header, in case of a write operation
* or if no additional data is needed return a empty array
*/
public function begin($path, $user, $mode, array $header, array $accessList)
{
$this->path = $this->getPathToRealFile($path);
$this->accessList = $accessList;
$this->user = $user;
$this->isWriteOperation = false;
$this->writeCache = '';
if ($this->session->decryptAllModeActivated()) {
$encryptedFileKey = $this->keyManager->getEncryptedFileKey($this->path);
$shareKey = $this->keyManager->getShareKey($this->path, $this->session->getDecryptAllUid());
$this->fileKey = $this->crypt->multiKeyDecrypt($encryptedFileKey, $shareKey, $this->session->getDecryptAllKey());
} else {
$this->fileKey = $this->keyManager->getFileKey($this->path, $this->user);
}
// always use the version from the original file, also part files
// need to have a correct version number if they get moved over to the
// final location
$this->version = (int) $this->keyManager->getVersion($this->stripPartFileExtension($path), new View());
if ($mode === 'w' || $mode === 'w+' || $mode === 'wb' || $mode === 'wb+') {
$this->isWriteOperation = true;
if (empty($this->fileKey)) {
$this->fileKey = $this->crypt->generateFileKey();
}
} else {
// if we read a part file we need to increase the version by 1
// because the version number was also increased by writing
// the part file
if (Scanner::isPartialFile($path)) {
$this->version = $this->version + 1;
}
}
if ($this->isWriteOperation) {
$this->cipher = $this->crypt->getCipher();
} elseif (isset($header['cipher'])) {
$this->cipher = $header['cipher'];
} else {
// if we read a file without a header we fall-back to the legacy cipher
// which was used in <=oC6
$this->cipher = $this->crypt->getLegacyCipher();
}
return array('cipher' => $this->cipher, 'signed' => 'true');
}
