A novel user-centric authorisation framework suitable for e-commerce in an open environment is proposed. The credential-based approach allows a user to gain access rights anonymously from various service providers who may not have pre-existing relationships. Trust establishment is achieved by making use of referrals from external third parties in the form of Anonymous Attribute Certificates. The concepts of One-task Authorisation Key and Binding Signature are proposed to facilitate pseudonymity in authorisation service. These mechanisms enhance user privacy and tackle the problem of scalability in identity-based access control systems.

As the use of information technology is increasing rapidly in organizations around the world, an important task is to design global networks with high security, eÆciency and functionality.While centralized systems have the advantages of simpli ed management, they face the problems of bottleneck and single point of failure.In this paper, we propose a new authorization scheme that operates over existing centralized authentication mechanisms.The goal is to enhance the performance and scalability in a centrally administered security architecture.A new technique of using one-shot authorization toke n s i s i n troduced.It facilitates a mechanism for updating or revocation of the access rights of users in online or o-line authorization models.A smart card is used as an authorization device in addition to its traditional function of user authentication.This scheme provides the mobility for users and the exibility in coping with dierent access control policies in a cross domain multi-application environment.