/**
* @brief Decrypt a keyfile without knowing how it was encrypted
* @param string $filePath
* @param string $fileOwner
* @param string $privateKey
* @return bool|string
* @note Checks whether file was encrypted with openssl_seal or
* openssl_encrypt, and decrypts accrdingly
* @note This was used when 2 types of encryption for keyfiles was used,
* but now we've switched to exclusively using openssl_seal()
*/
public function decryptUnknownKeyfile($filePath, $fileOwner, $privateKey)
{
// Get the encrypted keyfile
// NOTE: the keyfile format depends on how it was encrypted! At
// this stage we don't know how it was encrypted
$encKeyfile = Keymanager::getFileKey($this->view, $this->userId, $filePath);
// We need to decrypt the keyfile
// Has the file been shared yet?
if ($this->userId === $fileOwner && !Keymanager::getShareKey($this->view, $this->userId, $filePath)) {
// The file has no shareKey, and its keyfile must be
// decrypted conventionally
$plainKeyfile = Crypt::keyDecrypt($encKeyfile, $privateKey);
} else {
// The file has a shareKey and must use it for decryption
$shareKey = Keymanager::getShareKey($this->view, $this->userId, $filePath);
$plainKeyfile = Crypt::multiKeyDecrypt($encKeyfile, $shareKey, $privateKey);
}
return $plainKeyfile;
}
