D-Manager

Due to increase of cloud storage in recent years by the consumers there is a enormous popularity computer storage devices as well as in mobiles by using file syncing and sharing (FSS) services. 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 our approach we address the issue by using tracing and revoking traitors by using a new system model called anomaly detection and 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. Our system provides two security mechanisms which are traitor tracing and revocation to support digital forensics. The security and performance analysis shows that our construction is threshold provably secure. It consists of features like dynamic joining and revoking users, constant-size cipher texts and decryption keys, lower overloads for large-scale systems.