An authorization model for temporal data

The use of temporal data has become wide-spread in recent years, within applications such as data warehouses and spatiotemporal databases. In this paper, we extend the basic authorization model by facilitating it with the capability to express authorizations based on the temporal attributes associated with data, such as transaction time and valid time. In particular, a subject can specify authorizations based on data validity or data update time, using either absolute or relative time references. Such a specification is essential in providing access control for predictive data, or in constraining access to data based on currency considerations. We provide an expressive language for specifying such access control to temporal data, using a variation of temporal logic for specifying complex temporal constraints. We also introduce an easy-to-use access control mechanism for stream data.