D. Frey et al. (Eds.): ICDCN 2013, LNCS 7730, pp. 461–462, 2013. © Springer-Verlag Berlin Heidelberg 2013

POSTER: A Secure and Efficient Cross Authentication Protocol in VANET Hierarchical Model

Chandra Sekhar Vorugunti1 and Mrudula Sarvabhatla2

1 Dhirubhai Ambani Institute of Information and Communication Technology, Gandhi Nagar, India

Vorugunti_Chandra_Sekhar@daiict.ac.in 2 Sri Venkateswara University, Tirupati, India

mrudula.s911@gmail.com

Abstract. In 2011, Abhijith Das et al. [1] proposed a protocol based on hierarchical model for node authentication in group communication in VANETs and claimed that their protocol is robust against conventional security attacks. In this paper we will show that Abhijith Das et al. [1] scheme cannot withstand to various conventional security attacks and fails to provide authentication. We then present our improved scheme.

1 Authentication Scheme Proposed by Abhijith Das et al.

Abhijith Das et al. [1] scheme is based on VANET hierarchical Model and Polynomial Interpolation Scheme. (for PIS reading Shamir et al. and Mounita et al.)

1.1 Analysis of Weakness of Abhijith Das et al. Scheme

‘E’ can decrypt the message DK(M||T||NA) and can do following actions.

W1. Alter the identity NA i.e EK(M||T||NR). and sends the altered message to B. W2. Alter the message and broadcast an altered safety message EK(M’||T||NR).

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W3. Create arbitrary new false identities and frame safety messages like EK(M1||T||NR1), EK(M2||T||NR2) etc. W4. Add delay into the message EK(M||T+Δt||NR). These actions by adversary leads to timing attack, node impersonation attack, sybil attack, failure of assuring message integrity and entity authentication.

2 Our Proposed Authentication Protocol

In our scheme the session key is shared in very secure manner by the message EPubKeyB{M3|SK||T3||GK}. The decryption must be done with private key of B only. In our scheme A sends the message SigPriKeyA{MAC(ESK(M4),SK)} to B. Signing the message with the private key of A ensures that the message is from A only. Without providing the valid certificate issued by supervision CA, no intended receiver will respond to the invitation message. In the first place it’s not possible for A to create fake certificates. Hence in our scheme sybil attack is not possible. The certificate CertV[VPubKey] = VPubKey|| SigPriKeyCA[VPubKey||IDCA] are digitally signed by the CA with his private key. In our scheme ESK[M4||T],SigPriKeyA{MAC(ESK(M4||T),SK), the time stamp is concatenated to safety message. It’s not possible for any insider other than the intended recipient to decrypt the message using the session key SK. Hence our scheme resists all the major attacks. Once a new vehicle enters, the Abhijith Das et al. [1] scheme executes complete key generation algorithm which requires O(n2) operations where n is number of vehicles.

Reference

1. Abhijith, D., Dipanwitha, R.C., Anshul, R.: An Efficient Cross Authentication Protocol in VANET Hierarchical Model. International Journal of Mobile & Adhoc Network 1(1), 128–136 (2011)