1. A method for performing trust management decisions performed by a computer system comprising a processor and a communicatively coupled non-transitory computer-readable storage medium storing instructions that, when executed by the processor, cause the processor to perform the method, the method including: collecting, from other systems, a group of certificates, each certificate including at least one authorization associated with at least one principal; expressing authorizations using a structure that satisfies certain predefined properties; expressing each certificate as a function, wherein each function possesses one or more properties sufficient to ensure that a set of authorizations will have a fixpoint; computing a fixpoint of the authorizations, or an approximation thereof; and making a trust management decision using the result of said computing step.