Biblio

SM9 is an identity-based cryptography algorithm published by the State Cryptography Administration of China. With SM9, a user's private key for signing is generated by a central system called key generation center (KGC). When the owner of the private key wants to shirk responsibility by denying that the signature was generated by himself, he can claim that the operator of KGC forged the signature using the generated private key. To address this issue, in this paper, two schemes of SM9 digital signature with non-repudiation are proposed. With the proposed schemes, the user's private key for signing is collaboratively generated by two separate components, one of which is deployed in the private key service provider's site while the other is deployed in the user's site. The private key can only be calculated in the user's site with the help of homomorphic encryption. Therefore, only the user can obtain the private key and he cannot deny that the signature was generated by himself. The proposed schemes can achieve the non-repudiation of SM9 digital signature.

In VANET, vehicles periodically transmit beacon messages to the neighboring vehicles and the RSU. To establish the authenticity of these messages, a number of digital signature schemes have been proposed in literature. Many of these schemes enable an RSU to perform aggregate verification of the signatures to deal with high vehicle density scenarios. These schemes are either based on traditional PKC concept involving certificate management overhead or identity based cryptography having key escrow problem. Further, these schemes require the existence of OBU device which is resistant to side channel attacks. In this paper, we propose a hierarchical trusted authority privacy preserving certificateless aggregate signature scheme for VANET. In addition to providing message authentication, integrity and non-repudiation, our scheme is resistant to message forgeability attack. The proposed scheme assumes hierarchical organization of network such that vehicles operate under multiple trusted authorities (TA) which in turn are controlled by single root TA. Using our scheme, the entity could verify messages received from vehicles which operate under multiple TAs. The proposed scheme is free from key escrow problem and resistant to side channel attacks on OBU. It also possesses conditional linkability such that originator of a message could be revealed whenever required. Simulations confirm the efficient nature in terms of verification delay as compared to other well known schemes proposed in literature.

Ad hoc networks represent a very modern technology for providing communication between devices without the need of any prior infrastructure set up, and thus in an “on the spot” manner. But there is a catch: so far there isn't any security scheme that would suit the ad hoc properties of this type of networks and that would also accomplish the needed security objectives. The most promising proposals are the self-organized schemes. This paper presents a work in progress aiming at developing a new self-organized key management scheme that uses identity based cryptography for making impossible some of the attacks that can be performed over the schemes proposed so far, while preserving their advantages. The paper starts with a survey of the most important self-organized key management schemes and a short analysis of the advantages and disadvantages they have. Then, it presents our new scheme, and by using informal analysis, it presents the advantages it has over the other proposals.

Ad hoc networks represent a very modern technology for providing communication between devices without the need of any prior infrastructure set up, and thus in an “on the spot” manner. But there is a catch: so far there isn't any security scheme that would suit the ad hoc properties of this type of networks and that would also accomplish the needed security objectives. The most promising proposals are the self-organized schemes. This paper presents a work in progress aiming at developing a new self-organized key management scheme that uses identity based cryptography for making impossible some of the attacks that can be performed over the schemes proposed so far, while preserving their advantages. The paper starts with a survey of the most important self-organized key management schemes and a short analysis of the advantages and disadvantages they have. Then, it presents our new scheme, and by using informal analysis, it presents the advantages it has over the other proposals.