Multi-Layer Encryption for multi-level access control in Wireless Sensor Networks

The purpose of Multi-Layer Encryption (MLE) is to have only one cipher text, but users with different keys (e.g., in different groups) will obtain different levels of data after they decrypt with their own key. This property is especially useful in surveillance applications, which requires an efficient mechanism for multi-level data access. In this paper, we first address specific requirements for Wireless Sensor Networks (WSNs), and then propose a MLE scheme which has good properties of forward/backward secrecy, without the necessity of time synchronization. In this scheme, users only need to store a constant number of keys regardless of defined secret layers, and higher-level users are able to decrypt more data than lower-level users.