A Distributed Implementation Of The Transform Model

The Transform access-control model is based on the concept of transformation of access rights. It has previously been shown that Transform unifies a number of diverse access control mechanisms such as amplification, copy flags, separation of duties and synergistic authorization. It has also been shown that Transform has an efficient algorithm for safety analysis of the propagation of access rights (i.e., the determination of whether or not a given subject can ever acquire access to a given object). In this paper we propose a distributed implementation of Transform. Our design is based on capabilities with identities of subjects buried in them. This ensures unforgeability of capabilities as well as enables enforcement of "mandatory" controls on propagation of capabilities from one subject to another. The design provides for immediate, selective, partial and complete revocation on a temporary as well as permanent basis. Keywords: Distributed Systems, Secure Architectures, Capabilities 1..