This standard defines how the extension to the IETF Personal Assertion Token (PASSporT) [IETF RFC 8443, PASSporT Extension for Resource-Priority Authorization] and the associated Secure Telephone Identity Revisited (STIR) mechanisms are used to sign the Session Initiation Protocol Resource-Priority Header (SIP RPH) field of National Security / Emergency Preparedness (NS/EP) Priority Services calls (i.e., calls containing the ets and/or wps namespace parameter values) and convey assertions of authorization for Resource-Priority. Specifically, this standard provides a mechanism for an originating service provider to cryptographically sign the SIP RPH field of an authorized NS/EP Priority Service call and allow a receiving service provider to verify the validity of the authorization for Resource-Priority and act on the information with confidence (i.e., verifying that the RPH information has not been spoofed or compromised).