Access Control Methods Suitable for Stream Contents Delivery Cloud Services by Using Hash-Chain Based Key Derivation Schemes

In current content delivery cloud services, contents are usually encrypted for access control mechanism, so several key distribution/management schemes have been proposed. This paper proposes efficient key derivation schemes for the stream contents (or sequential contents) on cloud storage/delivery services, for example spreading video contents with time frames. It is assumed that a stream content consists of several atomic contents, and this atomic contents have been recognized as a totally ordered set. Now we consider access control for the totally ordered stream contents. On the contents distribution cloud system that consumers have to decrypt encoded stream contents by different keys for every atomic contents, this paper proposes efficient key derivation schemes for the stream contents.