Constraining RPKI Trust Anchors

This document describes an approach for Resource Public Key Infrastructure (RPKI) Relying Parties (RPs) to impose locally configured Constraints on cryptographic products subordinate to Trust Anchors (TAs). The ability to constrain a Trust Anchor operator's effective signing authority to a limited set of Internet Number Resources (INRs) allows Relying Parties to enjoy the potential benefits of assuming trust - within a bounded scope. The specified approach and configuration format allow RPKI operators to communicate efficiently about observations related to Trust Anchor operations.