STIR/SHAKEN attestation
What is STIR/SHAKEN attestation?
STIR/SHAKEN attestation is the A/B/C trust level a carrier cryptographically signs on an outbound call: A (full attestation) when the carrier knows the customer and the number being used, B (partial) when it knows the customer but not the number, or C (gateway) when the call transits beyond its verification reach. The level resolves at dial time from number ownership and any delegate certificate the tenant holds, and receivers weigh robocall risk on it before rendering the call.
More detail
Level resolution is per-call and ownership-driven: a call placed from a number the tenant owns resolves toward A, while unowned numbers and transit-edge traffic fall to B or C. If the ownership lookups behind resolution fail, the chain degrades open to C rather than blocking the call — the carrier of record signs outbound traffic and will not sign higher than the resolved level.
Your tenant's attestation posture is two policy levers rather than a send gate: `target_attestation` declares the level you intend outbound numbers to reach (default A), and `inbound_min_verification` declares which signed level you treat as verified inbound (default B). A posture snapshot then compares each originating number against those targets; the comparison flags gaps for reporting and never reroutes or gates a call.
Closing the gap to A is a numbering-side task — verify or port the numbers you originate from and keep delegate certificates current — because the level is resolved from ownership facts, not declared by configuration. Orbit documents the model and the downgrade edge cases in its attestation posture pages.
Frequently asked
- Can I get attestation A on every call?
- Only when the originating number is verified as yours — A requires the signing carrier to know both the customer and the number. Calls from unverified or transit numbers legitimately sign at B or C, and a carrier that signs higher than the evidence supports would be committing fraud.
- Does an attestation target block low-level calls?
- No. The target and floor levers measure and report — they flag originating numbers below target in the posture snapshot — but they never reject or reroute a call. The level itself is assigned by the signing carrier at dial time.
See also
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