Role-based trust assignment in trust management systems

Roles can. be a convenient construct for expressing the degree of trust between entities, based upon which further specification of responsibility and capability is made. Traditional role-based access control (RBAC) models, however, lack to support such a trust-relevant aspect of roles. In this paper, we describe the motivation and formal definition of a trust-enabled RBAC called TRUSTr. TRUSTr introduces a new component called trust assignment (TA). TA features trust-based cross-domain role association and supports entrusting or distrusting operations for the management of associated roles. By using Weeks' least fixpoint approach, we also discuss a feasible scheme for implementing TRUSTr.