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Abstract-Public Key Infrastructure (PKI) is the most widely used security mechanism for securing communications over the network. However, there are known performance issues, making it unsuitable for use in the Vehicular Networks (VNs). In this paper, we propose a Secure and Authenticated Key Management Protocol (SA-KMP) to overcome the shortcomings of the PKI. The SA-KMP scheme distributes repository containing the bindings of the entity's identity and its corresponding public key to each vehicle and Road Side Unit (RSU). By doing so, certificate exchanges and Certificate Revocation Lists (CRLs) are eliminated. Furthermore, SA-KMP scheme uses symmetric keys derived based on a 3D matrix based key agreement scheme to reduce the high computational costs of using asymmetric cryptography. We demonstrate the efficiency of the SA-KMP through performance evaluations in terms of transmission and storage overhead, network latency and key generation time. Analytical results show that the SA-KMP is more scalable and outperforms the certificate based PKI. Simulation results indicate that the key generation time of the SA-KMP scheme is less than that of the existing Elliptic Curve Diffie-Hellman (ECDH) and Diffie-Hellman (DH) protocols. In addition, we use Proverif to prove that the SA-KMP scheme is secure against an active attacker under the Dolev and Yao model and further show that the SA-KMP scheme is secure against Denial of Service (DoS), collusion attacks and a wide range of other malicious attacks.

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International audienceCryptographically Generated Addresses (CGA) are today mainly used with the Secure Neighbor Discovery Protocol (SEND). Despite CGA generalization, current standards only show how to construct CGA with the RSA algorithm and SHA-1 hash function. This limitation may prevent new usages of CGA and SEND in mobile environments where nodes are energy and storage limited. In this paper, we present the results of a performance and security study of the CGA and SEND. To significantly improve the performances of the CGA, we investigate first replacing RSA with ECC (Elliptic Curve Cryptography) and ECDSA (Elliptic Curve DSA), and second using the General-Purpose computing on Graphical Processing Units (GPGPU). Finally, a performance comparison between di erent hash algorithms (SHA-256, WHIRLPOOL,...) allows to prepare a better transition for the CGA when SHA-1 will be deprecated

Nowadays authentication in WirelessMesh Networks (WMN) refers to the 802.1X authentication methods or a Preshared key authentication, and makes use of certificates or shared secrets. In wireless environments, management of certificates is disadvantageous. Certificates require deploying a Public Key Infrastructure (PKI) and Certification Authorities (CA) and they require defining a certificate management policy to control the generation, transmission and revocation of certificates. Management of certificates is a cumbersome task and does not match the limited (power and memory) resources available at wireless nodes. Moreover it does not match the non permanent connectivity to CA. In this paper, we propose an ID-based method, as an alternative to the PKI, to provide nodes with private and public keys, and we present an authentication scheme that uses the ID-based cryptographic concepts. As illustrated in the paper, the authentication scheme is shown as suitable to the WMN networks.

This paper addresses the security issues of storing sensitive data in a cloud storage service and the need for users to trust the commercial cloud providers. It proposes a cryptographic scheme for cloud storage, based on an original usage of ID-Based Cryptography. Our solution has several advantages. First, it provides secrecy for encrypted data which are stored in public servers. Second, it offers controlled data access and sharing among users, so that unauthorized users or untrusted servers cannot access or search over data without client's authorization.

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