Abstract
With rapid growth of mobile users, protecting content from unauthorized
users become a complex problem. The concept of temporal role-based
access control reduces complexity of user management and restricts
access to specified time-slots. But, content privacy is still
questionable in case of system resources compromise unexpectedly.
Therefore, cryptographic solution for time-bound hierarchical content
management is an emerging problem. Most of the related schemes focused
on individual user keys and/or revocation, but not on time-bound keys.
Hence, these are not well suitable for subscription-based services like
pay-TV and newspaper. In this paper, we propose a cryptographic
time-bound access control with constant size time-bound keys. In our
scheme, subscribed time-slots embed into individual user keys to avoid
periodical broadcasting of temporal keys. We prove that our scheme is
selectively secure under chosen-ciphertext attack. We then discuss
cloud-based application to show the strategies of efficient revocation
and reduce user computational overheads.