An Efficient Anonymous Authenticated Key Agreement Protocol for Vehicular Ad-Hoc Networks Based on Ring Signatures and the Elliptic Curve Integrated Encryption Scheme

Abstract

Privacy in Vehicular Ad-hoc NETworks (VANETs) is one of the most important issues in order to successfully attract users to this new technology. In a common VANET use case two vehicles using the same application frequently need to exchange confidential application-related data. When it comes to a confidential data exchange, both vehicles need to authenticate each other and to agree on an encryption key. The new protocol proposed in this paper satisfies these requirements and, in addition, preserves the privacy of the vehicles. After execution of the protocol neither any vehicle in the communication range nor even the communication partners can reveal the identity of any of the communicating vehicles. To achieve this important goal we rely on the standardized Elliptic Curve Integrated Encryption Scheme (ECIES) and on ring signatures. We demonstrate how the advocated protocol can be used within GeoNetworking messages and evaluate its characteristics regarding the privacy of the participating vehicles. The presented results clearly show that the number of necessary pseudonyms for each vehicle may be reduced considerably when compared to a sole ECIES usage while still maintaining the privacy of the vehicles.