STIR is RFC 8224, PASSporT is RFC 8225, certificates are RFC 8226, and the SHAKEN extension is RFC 8588. Attestation levels are ATIS.
STIR, RFC 8224, puts a signed identity in the SIP Identity header. The token format is PASSporT, RFC 8225, and the certificates used with that signature are RFC 8226.
RFC 8588 is the SHAKEN PASSporT extension, and it is how a SHAKEN profile rides on the IETF token. Verification that fails, or an Identity header that is absent, means you do not present the From value as STIR-authenticated.
Attestation levels people label A, B, and C are an ATIS SHAKEN concept. They are defined by ATIS SHAKEN specifications, and you confirm the current ATIS document before you teach or display those levels. This lesson does not invent an ATIS document number or a date.
The FCC call-authentication page is the public regulator summary to cite beside those specifications. P-Asserted-Identity does not fill in for a missing Identity header, and a failed signature stays failed.
Room: STIR, PASSporT, and SHAKEN
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