In this paper we design and analyze hierarchical key assignment schemes which are provably-secure and support dynamic updates to the hierarchy with local changes to the public information and without requiring any private information to be re-distributed. We first consider the problem of constructing a hierarchical key assignment scheme by using as a building block a symmetric encryption scheme. We propose a new construction which is provably secure with respect to key indistinguishability, requires a single computational assumption, and improves on previous proposals. Then, we show how to reduce key derivation time at the expense of an increment of the amount of public information, by improving a previous result. Finally, we show how to construct a hierarchical key assignment scheme by using as a building block a public-key broadcast encryption scheme. In particular, one of our constructions provides constant private information and public information linear in the number of classes in the hierarchy.
Category / Keywords: Access control, key assignment, provable security, efficient key derivation. Date: received 21 Dec 2006, last revised 3 Jan 2007 Contact author: masucci at dia unisa it Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation Version: 20070103:181533 (All versions of this report) Short URL: ia.cr/2006/479 Discussion forum: Show discussion | Start new discussion