Abstract. Access control for semi-structured data is nontrivial, as witnessed by the number of access control approaches in recent literature. Recently a case has been made for expressing access constraints at finer levels of granularity on data nodes and extending constraints to structural relationships. In this paper, we introduce a rewrite-based approach for access constraint enforcement, based on the ACXESS framework we developed at Indiana University. This approach consists a set of rewrite rules that take advantage of the Security Annotated Schema (SAS), an internal representation for such virtual security views, and is capable of rewriting user queries against security views into queries against the source data, while honoring the access constraints.