Short Paper: Limitations of Key Escrow in Identity-Based Schemes in Ad Hoc Networks

Recently, identity-based cryptography (IBC) schemes are considered as a tool to secure ad hoc networks. In this work we focus on the role of the Trust Authority (TA) as a key escrow, a property that is inherent to all IBC schemes. We explore the special role of key escrow in ad hoc networks and show that this role significantly differs from key escrows in other networks. We introduce a series of adversary models for dishonest TAs in ad hoc networks, including a new model where a TA uses spy nodes that record communications in the network and report them to the TA. Our analytical results show that in many ad hoc network applications the TA can be prevented from being a key escrow.