What is STIR/SHAKEN?
STIR/SHAKEN is a US framework that cryptographically signs caller ID so receiving carriers can verify a call genuinely originated from the number it displays, used to combat caller ID spoofing.
The originating carrier attaches a signed token attesting to its relationship with the caller. Full attestation means the carrier knows the customer and confirms their right to use that number; lower levels mean it knows the customer but not the number, or neither.
Receiving carriers use that attestation when deciding how to present a call. Poorly attested traffic is what ends up labelled "Scam Likely" or filtered before it rings.
For a business making outbound calls this matters more than the technology suggests: a legitimate company whose calls are badly attested will see answer rates fall without any obvious cause. Registering caller ID properly, and pairing it with CNAM so the business name displays, is the practical countermeasure.
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