CloudS: A Multi-Cloud Storage System with Multi-Level Security

With the increase of data quantity, people have begun to attach importance to cloud storage, however, traditional single cloud can’t ensure the privacy of users’ data to a certain extent. To solve the security issue, we present a multi-cloud storage system called CloudS which spreads data over multiple cloud storage servers by using a new kind of XOR-based non-systematic erasure codes - Privacy Protecting Codes (PPC). For better user experiences and tradeoffs between security and performance, CloudS provides multiple levels of security by a variety of combinations of compression, encryption and coding schemes. In addition, we also put forward a novel Parallel Cyclic Encryption (PCE) scheme to achieve random secret key protection which attains high security and performance. We implement CloudS as a web application which doesn’t require users to perform complicated operations on local.