How to interpret SHAKEN/STIR verstat parameters and ensure secure call identity verification
As part of our ongoing efforts to improve the SHAKEN/STIR framework, Telnyx has introduced additional values to the verstat parameter in our SIP headers.
This update provides Telnyx customers with more granular information regarding originating Caller ID attestation and verification results.
The verstat parameter is included in the P-Asserted-Identity SIP header and includes information about the caller identity validation and attestation level.
Previously, the possible values were TN-Validation-Passed, TN-Validation-Failed, or No-TN-Validation depending on verification results of the PASSPorT and attestation level.
This verification is done for inbound calls from the PSTN as well as on-net calls from Telnyx customers to other Telnyx customers.
Introducing two additional verstat values:
TN-Validation-Passed-B: Indicates that identity header verification is successful, and the call has a B attestation.
TN-Validation-Passed-C: Indicates that identity header verification is successful, and the call has a C attestation.
With these new values, Telnyx customers will have more detailed information about the origin of incoming calls and the level of attestation.
This can be especially useful for customers who need to verify the identity of incoming calls to prevent fraud or for regulatory compliance.
It's important to note that these new verstat values will be included in the SIP headers passed along to Telnyx customers.
This means that customers can access this information directly through their own systems and tools.
Verstat Values Summary
Identity header verification is successful, and the caller has an A attestation
Identity header verification failed as the certificate Telnyx received was deemed invalid.
No verification took place because the Identity header was not provided
Identity header verification is successful, and the caller has a B attestation
Identity header verification is successful, and the caller has a C attestation
Below you can find a P-Asserted-Identity example:
For more information on the SHAKEN/STIR framework and how it works, please visit our resource center.