Identity Based Encryption Using Multiple Trust Authorities in Ad Hoc Networks

Ad hoc networks are becoming more and more popular as the use of mobile computing devices increases. While ad hoc networks have many advantageous properties, they also pose several security challenges which are unique to networks of this kind. One of the main challenges that ad hoc networks have to face is authentication. Authentication is difficult to achieve in ad hoc networks because some type of key distribution system is needed to develop the authentication mechanism. Public key cryptosystems are a possible solution to this challenge, but then a certain level of trust must be established before the keys may be used. In many cases this can be accomplished using a certificate authority or central trust authority. However, this brings about many contradictions to the properties of ad hoc networks. This paper will present some of the security challenges and opportunities encountered when utilizing ad hoc networks. Security attributes will be discussed so that the security of a network may be evaluated. Following the discussion of the security attributes, identity based encryption schemes based on the Weil pairing, presented by Boneh and Franklin in [1], will be presented. Identity based encryption will then be enhanced using the idea of multiple trust authorities, which was presented originally by Chen et al in [2]. Finally, ad hoc networks using multiple trust authorities in an identity based encryption scheme will be discussed. Throughout the paper two examples (sections 2.3 and 2.4) will be used to illustrate the ideas of [1], [2], and their applications to ad hoc networks.