A time-bound hierarchical key assignment scheme is a method to assign time-dependent encryption keys to a set of classes in a partially ordered hierarchy, in such a way that the key of a higher class can be used to derive the keys of all classes lower down in the hierarchy, according to temporal constraints.In this paper we design and analyze time-bound hierarchical key assignment schemes which are provably-secure and efficient. We first consider the unconditionally secure setting and we show a tight lower bound on the size of the private information distributed to each class. Then, we consider the computationally secure setting and obtain several results: We first prove that a recently proposed scheme is insecure against collusion attacks. Hence, motivated by the need for provably-secure schemes, we propose two different constructions for time-bound hierarchical key assignment schemes. The first one is based on symmetric encryption schemes, whereas, the second one makes use of bilinear maps. These appear to be the first constructions of time-bound hierarchical key assignment schemes which are simultaneously practical and provably-secure. Copyright 2006 ACM.
Provably-secure time-bound hierarchical key assignment schemes / Ateniese, Giuseppe; Alfredo De, Santis; Anna Lisa, Ferrara; Barbara, Masucci. - (2006), pp. 288-297. (Intervento presentato al convegno CCS 2006: 13th ACM Conference on Computer and Communications Security tenutosi a Alexandria, VA nel 30 October 2006 through 3 November 2006) [10.1145/1180405.1180441].
Provably-secure time-bound hierarchical key assignment schemes
ATENIESE, GIUSEPPE;
2006
Abstract
A time-bound hierarchical key assignment scheme is a method to assign time-dependent encryption keys to a set of classes in a partially ordered hierarchy, in such a way that the key of a higher class can be used to derive the keys of all classes lower down in the hierarchy, according to temporal constraints.In this paper we design and analyze time-bound hierarchical key assignment schemes which are provably-secure and efficient. We first consider the unconditionally secure setting and we show a tight lower bound on the size of the private information distributed to each class. Then, we consider the computationally secure setting and obtain several results: We first prove that a recently proposed scheme is insecure against collusion attacks. Hence, motivated by the need for provably-secure schemes, we propose two different constructions for time-bound hierarchical key assignment schemes. The first one is based on symmetric encryption schemes, whereas, the second one makes use of bilinear maps. These appear to be the first constructions of time-bound hierarchical key assignment schemes which are simultaneously practical and provably-secure. Copyright 2006 ACM.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.