Abstract

In this paper we give a classification of delegation schemes into four main classes. To solve the problem with simply chained tokens in cascaded delegations we introduce the concept of hierarchical delegation tokens. To realize this concept we use the Schnorr signature scheme and self--certified public keys introduced by Girault. We describe the first approach for hierarchical key generation based on an unregarded idea of Gunther and the generation of designated verifier signatures. Using these tools, we present efficient delegation schemes for the four main classes, which are efficient in generating and using delegation keys compared with other existing approaches. This is one of the few works, that combines cryptographic algorithms and protocols to benefit for the complexity and the efficiency of the resulting delegation mechanisms.

Citations