Identity based delegation network

Abstract

Delegation of authorities is a common practice in various organizations. The way delegation is performed can be quite complicated. To capture possible delegation structures, the concept of delegation network is proposed, so that anyone can be convinced of who obtained delegation from whom in order to produce the final proxy signature. In this paper, we consider the delegation network for identity-based (ID-based) scenario. Since the public key is just a string denoting the user's identity, certificate management is simplified. Proxy signature schemes have been devised to delegate signing authorities. We show that a trivial attempt of extending an existing ID-based proxy signature may result in an insecure scheme. After that we propose a building block of our ID-based delegation network, which is an ID-based proxy signature supporting batch verifications. Our proposed ID-based delegation network is flexible in the sense that the whole delegation network does not need to be known in advance. Our proposal is provably secure under the random oracle model. © Springer-Verlag Berlin Heidelberg 2005.