Chae Duk Jung

A Robust Conditional Privacy-Preserving Authentication Protocol in VANET

Recently, Lu et al. proposed an efficient conditional privacy preservation protocol, named ECPP, based on group signature scheme for secure vehicular communications. However, ECPP dose not provide unlinkability and traceability when multiple RSUs are compromised. In this paper, we make up for the limitations and propose a robust conditional privacy-preserving authentication protocol without loss of efficiency as compared with ECPP. Furthermore, in our protocol, RSUs can issue multiple anonymous certificates to an OBU to alleviate system overheads for validity check of RSUs. In order to achieve these goals, we consider a universal re-encryption scheme as our building block.

Chosen-Ciphertext secure certificateless proxy re-encryption

In this paper we introduce the notion of certificateless proxy re-encryption and also give precise definitions for secure certificateless proxy re-encryption schemes. We present a concrete scheme based on bilinear pairing, which enjoys the advantages of certificateless public key cryptography while providing the functionalities of proxy re-encryption. Moreover, the proposed scheme is unidirectional and compatible with current certificateless encryption deployments. Finally, we show that our scheme has chosen ciphertext security in the random oracle model.

An Efficient Anonymous Authentication Protocol for Secure Vehicular Communications

As vehicular communications bring the promise of improved road safety and optimized road traffic through cooperative systems applications, it becomes a prerequisite to make vehicular communications secure for the successful deployment of vehicular ad hoc networks. In this paper, we propose an efficient authentication protocol with anonymous public key certificates for secure vehicular communications. The proposed protocol follows a system model to issue on-the-fly anonymous public key certificates to vehicles by road-side units. In order to design an efficient authentication protocol, we consider a key-insulated signature scheme for certifying anonymous public keys of vehicles to the system model. We demonstrate experimental results to confirm that the proposed protocol has better performance than other protocols based on group signature schemes.

A robust and efficient anonymous authentication protocol in VANETs

Recently, Lu et al. proposed an efficient conditional privacy preservation protocol, named ECPP, based on group signature scheme for generating anonymous certificates from roadside units (RSUs). However, ECPP does not provide unlinkability and traceability when multiple RSUs are compromised. In this paper, we make up for the limitations and propose a robust and efficient anonymous authentication protocol without loss of efficiency as compared with ECPP. Furthermore, in the proposed protocol, RSUs can issue multiple anonymous certificates to an OBU to alleviate system overheads for mutual authentication between OBUs and RSUs. In order to achieve these goals, we consider a universal re-encryption scheme and identity-based key establishment scheme as our building blocks. Several simulations are conducted to verify the efficiency and effectiveness of the proposed protocol by comparing with those of the existing ECPP.

Multi-receiver Certificate-Based Encryption and Application to Public Key Broadcast Encryption

In this paper we firstly introduce the notion of multi- receiver certificate-based encryption that avoids the inherent key escrow problem while preserving the implicit certification of multi-receiver identity-based encryption. We also construct a highly efficient multi-receiver certificate-based encryption scheme which eliminates pairing computation to encrypt a message for multiple receivers. Moreover, the proposed scheme only needs one pairing computation for decrypting the ciphertext. We compare our scheme with the most efficient multi-receiver identity-based encryption scheme[2] in terms of the computational point of view, and show that our scheme provides better efficiency than [2]. Finally, we discuss how to properly transform our scheme into a new public key broadcast encryption scheme based on subset-cover framework, which enjoys the advantages of certificate-based encryption.

Efficient Anonymous Authentication Protocol Using Key-Insulated Signature Scheme for Secure VANET

In this paper, we propose an efficient authentication protocol with conditional privacy preservation for secure vehicular communications. The proposed protocol follows the system model to issue on-the-fly anonymous public key certificates to vehicles by road-side units. In order to design an efficient message authentication protocol, we consider a key-insulated signature scheme for certifying anonymous public keys of vehicles to such a system model. We demonstrate experimental results to confirm that the proposed protocol has better performance than other protocols based on group signature schemes.

An Improved Flexible Access Control Scheme for JPEG2000 Codestreams

JPEG2000 is the newest image coding standard which provides flexible scalability. Designing an encryption system for scalable JPEG200 codestream is becoming a new challenge. Wu et al. (2007) proposed a flexible access control scheme for JPEG2000 codestream. However, it needs key regeneration whenever users change the preferred progression order. In this paper, we propose an improved flexible access control scheme for JPEG2000 codestreams based on multi-dimensional hash chains (MDHC), in which the keys need not to be regenerated whenever different progression order of packets is required. In particular, we employ multiple hash chains to generate a series of keys to encrypt each packet in the codestream. Furthermore, users can access the encrypted codestream according to any authorized combinations of resolution, quality layer and precinct with as few as possible keys. Also, our proposed scheme is secure against collusion attack as well as unauthorized access.

An Efficient Anonymous Authentication Protocol Based on Multiple Anonymous Certificates in VANET

ABSTRACT Until now, some protocols have been presented to provide vehicle’s anonymity and unlinkability in VANET by means of issuing multiple anonymous certificates to each vehicle from the trust authority, or shot-time anonymous certificate to a vehicle after mutual authentication between a Roadside Unit (RSU) and the vehicle. However, these protocols have high overheads of the trust authority, RSUs and vehicles for generating anonymous certificate. In this paper, we propose an efficient anonymous authentication protocol, in which RSUs can issue multiple shot-time anonymous certificates to a vehicle to alleviate system overheads for mutual authentication between vehicles and RSUs. Several simulations are conducted to verify the efficiency of the proposed protocol in terms of RSU valid serve ratio and vehicles computational costs. Moreover, the proposed protocol provides unlinkability and traceability when multiple RSUs are compromised, whereas previous protocols do not provide unlinkability and traceability.Keywords:VANET(Vehicular Ad-hoc Network), Privacy Protection, Anonymous Authentication, Multiple Anonymous Certificates