Georgetown University National policy defines telephone numbering governance. One area of such governance are the policies applied to the Secure Telephone Identity Credentials defined in RFC 8226. Nations have policies for the acceptable trust anchors for these credentials. This document defines an IANA registry that enables a SIP call recipient in one country to validate the signature, as defined in RFC 8224, that originates in another country useing an appropriate trust anchor for the signer's certification path, per the origination country's trust anchor policy.