Towards Enabling Secure Web-Based Cloud Services using Client-Side Encryption

The recent years have brought an influx of privacy conscious applications, that enable strong security guarantees for end-users via end-to-end or client-side encryption. Unfortunately, this application paradigm is not easily transferable to web-based cloud applications. The reason for this lies within adversary's enhanced control over client-side computing through application provided JavaScript. In this paper, we propose CryptoMembranes - a set of native client-side components that allow the development of web applications which provide a robust isolation layer between the client-side encrypted user data and the potentially untrusted JavaScript, while maintaining full interoperability with current client-side development practices. In addition, to enable a realistic transition phase, we show how CryptoMembranes can be realized for currently existing web browsers via a standard browser extension.