PHE: An Efficient Traitor Tracing and Revocation for Encrypted File Syncing-and-Sharing in Cloud

 PHE: An Efficient Traitor Tracing and Revocation for Encrypted File Syncing-and-Sharing in Cloud

 Recently, many more enterprises have moved their data into the cloud by using file syncing and sharing (FSS) service, but bring-your-own-device (BYOD) policies and greatly increasing mobile devices have in fact raised a new challenge for preventing the player/decoder abuse in the FSS service. In this paper, we address this issue using a new system model with anomaly detection, tracing and revoking traitors. To implement this model, we present a new threshold cryptosystem, called Partially-ordered Hierarchical Encryption (PHE), which implements the partial-order key hierarchy, similar to role hierarchy in Hierarchical RBAC, in public-key infrastructure.