A flexible and extensible architecture allows for secure searching across an enterprise. Such an architecture can provide a simple Internet-like search experience to users searching secure content inside (and outside) the enterprise. The architecture allows for the crawling and searching of a variety of sources across an enterprise, regardless of whether any of these sources conform to a conventional user role model. The architecture further allows for security attributes to be received at query time, for example, in order to provide real-time secure access to enterprise resources. The user query also can be transformed to provide for dynamic querying that provides for a more current result list than can be obtained for static queries.