Efficient ID-based Message Authentication with Enhanced Privacy in Wireless Ad-hoc Networks

Message authentication is one of the most effective ways to thwart unauthorized messages from being transmitted in wireless ad-hoc networks such as wireless sensor networks (WSNs) and vehicular ad-hoc networks (VANETs). For this reason, many message authentication schemes have been developed, based on either symmetric-key cryptosystems or public-key cryptosystems. Public-key cryptosystems have simpler key management and are easier to scale, thus are more suitable for message authentication. Among all kinds of public-key cryptosystems, identity based cryptosystem is the most attractive since the public keys can be derived locally. In this paper, we propose an efficient message authentication with enhanced privacy (IMAEP) scheme based on ring signature and identity based signature. We prove that besides unconditional privacy, the proposed scheme can achieve enhanced privacy which can defend against full key exposure attack. We also prove that the proposed scheme can achieve unforgeability against adaptive chosen-message-and-identity attack. Through comparing the proposed scheme with the scheme proposed in [1] with the same level of enhanced privacy, we demonstrate that our scheme has the following advantages: 1) our scheme has much lower computational overhead, 2) our scheme can retain unconditional privacy.