What is STIR/SHAKEN?
STIR/SHAKEN is a framework used in telecoms to help combat caller ID spoofing and unwanted robocalls.
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STIR stands for Secure Telephone Identity Revisited.
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SHAKEN stands for Signature-based Handling of Asserted information using toKENs.
Together, they work by digitally signing calls at the network level. This signature lets carriers verify that the Caller ID showing on your phone hasn’t been tampered with and that the call really comes from who it says it does.
Why Does It Matter?
Regulators, especially in North America, require VoIP and telephony providers to use STIR/SHAKEN to help reduce fraud and nuisance calls. More countries are considering similar systems.
If your calls are signed correctly, they are less likely to be blocked or flagged as spam by recipient networks.
How STIR/SHAKEN Signing Works
When you make a call, your provider’s system uses attestation levels to confirm your right to use the Caller ID. This “attestation” then becomes part of the digital signature sent with the call.
Attestation Levels Explained
There are three levels:
✅ Full Attestation (A)
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The provider knows the caller and has confirmed their right to use the Caller ID.
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Example: A business calling out using its own verified main number.
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Highest trust level, best for call delivery.
⚠️ Partial Attestation (B)
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The provider knows the caller, but cannot fully confirm the right to use the Caller ID.
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Example: Calls that go through a PBX or third-party system where the caller sets the ID themselves.
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Medium trust level, still likely to be delivered, but more chance of spam tagging.
❗Gateway Attestation (C)
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The provider can only confirm that the call entered their network.
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They do not know the caller’s identity or cannot verify the Caller ID.
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Lowest trust level, more likely to be blocked or flagged.
How Does This Affect Me?
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If you want your calls to be trusted, your Caller ID should always be accurate, valid, and verified.
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With Voyced, your calls are routed using Premium Plus quality, and we work to ensure the highest possible attestation level whenever possible.
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If you need to set your own Caller ID, make sure you truly own the number or have permission to use it. Abuse or spoofing can downgrade your trust level, or worse, get your calls blocked entirely.
✅ Key Takeaway
Full Attestation = maximum trust
The more your Caller ID can be verified, the smoother your calls will be delivered worldwide.
Important:
Voyced can only provide Full Attestation for numbers that are in our system and fully verified by us. If you set a Caller ID for a number that is not hosted with Voyced, you set your own ID manually or requested the hardcoded Caller ID not to be set, we will usually only be able to sign your call with Gateway Attestation (or perhaps Partial, depending on how and what we can verify).
Always make sure your Caller ID is valid and properly linked to your account if you want the best chance of Full Attestation.
If you have any questions about STIR/SHAKEN, attestation, or Caller ID options, contact us, we’re here to help.
Last updated: 01/07/2025
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All information provided is copyrighted and purely informative in nature. It is maintained by Voyced with the greatest of care using reliable sources only.
Given the fast evolution of the telecom sector, Voyced does not offer any guarantee about the accuracy and completeness of the information offered.
We explicitly do not give anyone permission to use this information in any other way than to inform themselves about what (legal) requirements there may be and they need to comply with when registering Services and/or DIDs with Voyced.
