Access control for untrusted content distribution clouds using unidirectional re-encryption

We present a secure content distribution cloud (CDC) system to enforce access control over encrypted data stored in untrusted CDCs. In particular, we demonstrate how a modified form of unidirectional proxy re-encryption can be used to realize coarse grained access control in a distributed environment without a proxy. We then theorize a new unidirectional re-encryption scheme that can be used in our system, including a concrete set of properties that must be satisfied to convert a proxy re-encryption system into a unidirectional re-encryption system.