Attribute-based Credentials:Theory And Applications

With the rapid development of information technology,while people are enjoying the convenience enabled by information technology,the service providers are collecting users' private information.For example,when a user requests service,the identity information is usually required as a proof of his/her subscription while the service providers can learn the user's identity.For the purpose of preserving privacy in certain authentication scenarios,a kind of anonymous credentials are proposed.Attribute-based credentials(ABCs)are one of these anonymous credentials,which provide a powerful tool to preserve privacy in applications,of which the two important properties: authenticity and anonymity are achieved using cryptography.In this thesis,we first introduce some important cryptographic primitives,and show how to use these primitives to construct an ABCs system.Then we focus on the vehicular ad-hoc networks(VANETs)and propose our scheme,which is efficient and privacypreserving.Since the existing schemes have disadvantages in pseudonyms chaning problem or group-member auditing problem.Our proposed scheme eliminates these two problems in an efficient way.Our proposed scheme is based on ring signature scheme,and is very different from other existing schemes by combining ID-based cryptography and symmetric cryptography,and is efficient to fulfill the verification of ring members.Furthermore,we compare our proposed scheme with other existing schemes,and summarize the properties of our scheme.The results show that the security level of our scheme is higher and the road-side units' capacities are much lower.