A computer implemented access control system, the system includes a database for storing a serialized version of an XACML permissions hierarchy. The system also includes a memory for storing an original version of the XACML permissions hierarchy, and an XACML serialization engine configured to convert the XACML permissions hierarchy into the serialized version, wherein the serialized version contains a listing of at least a portion of the predicates possible in the XACML permission hierarchy and the effect on each of the portion of the predicates.