An Improved Binary Authentication Tree Algorithm for Vehicular Networks

Abstract

Vehicular networks are gaining popularity because vehicular communications are able to help minimize accidents, improve traffic conditions, etc. To avoid malicious attacks and potential abuse, employing digital signatures is widely recognized as the most efficient approach for vehicular networks. However, when the number of signatures received by a roadside unit (RSU) becomes large, a scalability problem emerges immediately: it can be difficult for the RSU to sequentially verify every received signature within 100-300ms as required by the current Dedicated Short Range Communications (DSRC) broadcast protocol. Jiang et al. proposed a robust and efficient signature scheme for vehicular-to-infrastructure communications, called binary authentication tree. In this paper, we show that their binary authentication algorithm is insecure to at least two attacks. The first attack shows that the original binary authentication algorithm is universally forgeable under chosen-message attacks, i.e. the attacker can forge other vehicles' authentication on any message under chosenmessage attack. The second attack shows that the original binary authentication algorithm is universally forgeable, i.e., the attacker can forge other vehicles' authentication on any message at will. Although Jiang et al.'s scheme is insecure, it can be repaired. Using the binary authentication tree model, we repair their scheme in order to make it provably secure and efficient.

A Lightweight BT-Based Authentication Scheme for Illegal Signatures Identification in VANETs

“…n authentic signatures n signatures with b ≥ 1 fake signatures Liu et al [12] 3P C + SC = 4.02513 ms -Tzeng et al [16] 2P C + SC = 2.68513 ms -Azees et al [19] (1 + n)P C = 1.34(1+n) ms -Gu et al [20] nP C + 3nEC = 7.43n ms -Jiang et al Jiang et al [21], Wang et al [22], and Shim et al [36], in batch signatures verification process, with and without b ≥ 1 fake signatures.…”

“…Main feature: an IBS cryptography-based authentication scheme with binary authentication tree (BAT) mechanism for illegal signatures identification. Limitation: insecure against forgery attacks, replay attacks, and Sybil attacks [22], [36].…”

“…In BAT, the RSUs can quickly distinguish bogus messages from all the authentic ones, allowing them to withstand message flooding attacks to a great extent. However, in 2012, Wang et al [22] discovered that Jiang et al's BAT cannot resist the forgery attack. They launch two types of attacks on any message, in which the adversary can counterfeit the batch verification and the signatures of the other vehicles.…”

“…supposedly suitable to encounter a situation, that very possibly happens in the real world, where the adversary broadcasts some forged message to the network. At this stage, when such a condition happens, from the above-compared schemes, only Jiang et al's[21], Wang et al's[22], and our schemes, that have an illegal signatures identification property. Based on the discussion in Section I, a verifier (RSU or vehicle) has to verify around 600 messages per second.…”