PASSporT — Personal Assertion Token
What is PASSporT?
A PASSporT (Personal Assertion Token) is the cryptographically signed token that carries a STIR/SHAKEN attestation claim on a voice call. At call setup the originating provider signs a PASSporT — a compact JWT recording the calling number, called number, timestamp, and one attestation level — and attaches it to the SIP invite in the Identity header, so the terminating carrier can verify the signature before it decides how to render the call.
More detail
The level the PASSporT asserts is the A/B/C grade surfaced in attestation posture: A (full) when the signing provider authenticated the caller and verified its right to the calling number, B (partial) when it authenticated the caller but could not verify the number, and C (gateway) when only the call's entry point is known. The Devotel wholesale softswitch signs the token at exactly the level the dial path resolved — never higher than the evidence supports.
Because the PASSporT is signed, the level it claims comes from ownership evidence, not a declared configuration. For bring-your-own-number (BYON) caller IDs, registering a delegate certificate under the ATIS-1000092 delegated-attestation standard lifts the numbers it covers from C to B; the certificate is a tenant-supplied artifact, so B is its deliberate ceiling and A still requires a number your organization owns.
Inbound, the reverse flow runs: the upstream carrier's PASSporT is verified on the inbound edge and the result (A/B/C, failed, or none) feeds your inbound routing rules, so a signed claim you can trust arrives ahead of the call itself.
Frequently asked
- Is a PASSporT the same thing as STIR/SHAKEN?
- No — STIR/SHAKEN is the industry framework (ATIS-1000074) and a PASSporT is the signed token the framework moves through the SIP Identity header. Every STIR/SHAKEN call carries a PASSporT; the framework is the protocol, the token is the object it transports.
- Can I choose the attestation level my outbound PASSporTs claim?
- No. The level resolves from number ownership and any registered delegate certificate, and the signing provider signs at exactly that resolved level. You can set a target level for reporting, but the signed claim itself always reflects what the ownership evidence supports.
See also
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