A flexible way of expressing trust policies using, for example, XML. Multiple statement types may be expressed for a single authority type. Statement types may include less than all of the statements made by an authority type. Authority types may be defined using any manner interpretable by the computing system using the trust policy. In addition, trust policies may be updated as trust levels change. Even multiple trust policies may be used with reconciliation between the multiple trust policies being accomplished by using the more restrictive trust policy with respect to an assertion.