What Is Stir/Shaken and How Does It Work?

Imagine a world without robocalls

Photo of someone holding a smartphone with an "incoming phone call" screen.


Robocalls and other spam phone calls with spoofed phone numbers can often seem like an unstoppable, unending nuisance, but there's a new technology on the horizon that may at least reduce the number of them.

It's called STIR/SHAKEN and it's a promising solution to those bothersome, unwanted calls. Let's take a look at what STIR/SHAKEN is, how it works, and how it may affect your phone service once implemented.

When it comes to STIR/SHAKEN you may also see or hear this technology being referred to as "SHAKEN/STIR." Both terms are considered to be the correct usage for this technology.


The term "STIR/SHAKEN" comes from a combination of two acronyms: STIR and SHAKEN. According to the United States Federal Communications Commission (FCC), each acronym refers to "a framework of interconnected standards." STIR stands for the Secure Telephone Identity Revisited standard and SHAKEN stands for the Signature-based Handling of Asserted information using toKENs standard.

What this means for consumers is that the combination of these standards results in a phone call authentication technology that helps reduce spoofed calls and robocalls by providing a way for phone service carriers to verify the true identity behind a given phone call before it reaches its intended recipient.

Since STIR/SHAKEN could help authenticate the source of these calls, it could make it easier for phone carriers (or call-blocking services) to block more robocalls so they don't reach customers in the first place. It could also grant customers access to a more accurate caller ID feature that lets them know the unknown caller is calling from a verified number and the call probably isn't spam.

How STIR/SHAKEN Blocks Spoof Calls and Robocalls

To understand how STIR/SHAKEN works, you need to understand how spoofed calls work.

A spoofed call is usually a spam or robocall in which someone has deliberately changed the listed phone number of an incoming call on your caller ID to reflect a fake phone number instead of the real number that's associated with the source of the spam phone call. This allows the caller to hide their own number and/or use a fake number that appears legitimate to better entice people to pick up the call.

As New York Magazine's Intelligencer notes, such spoofing can be particularly dangerous if a spammer decides to place a spoofed call that appears to be from legitimate financial institutions or government agencies in an effort to get people to release important, private personal data. And with spoofing techniques becoming more and more sophisticated, call authentication technologies like STIR/SHAKEN may become increasingly important in the fight against robocalls.

Here's How STIR/SHAKEN Is Expected to Work

Essentially, when a phone call is placed, the incoming call's caller ID is marked by or "signed" with a digital certificate confirming the true identity of the caller (namely the correct phone number and the caller's carrier). This certificate would be provided by the caller's phone carrier.

The phone carrier of the phone call's intended recipient would then inspect the certificate and verify whether or not the caller's digital certificate is valid. If valid, the call is passed to the intended recipient, and shows up on the recipient's caller ID marked as "verified." This could also result in "unverified" calls being blocked outright by call-blocking services, meaning customers could either choose not to answer an "unverified" call or rely on a call-blocking service that uses STIR/SHAKEN's caller ID data to block the calls.

How STIR/SHAKEN May Affect Your Phone Service

STIR/SHAKEN isn't just a theoretical solution to the robocall problem, as carriers are already working toward implementing this technology into their own services.

NBC News reports Verizon and T-Mobile use STIR/SHAKEN to verify calls within their own networks, with many other carriers planning to implement STIR/SHAKEN "by the end of 2019."

As of May 2019, the U.S. and Canada are the only countries confirmed to have plans to implement STIR/SHAKEN. However, STIR/SHAKEN verification between the two countries hasn't been confirmed yet and may not happen until 2020, if at all.

That said, here are a few things you can expect to happen with the implementation of STIR/SHAKEN with your phone service.

It May Reduce Robocalls, but It's Unlikely to Eliminate All of Them

While the verification technology of STIR/SHAKEN may reduce the number of robocalls you receive, it's unlikely to eliminate all of them. As expected, scammers who really want to do this may still resort to paying to use STIR/SHAKEN verified numbers for spoofed calls anyway.

It's Also Unlikely to Help Reduce Landline Robocalls

According to New York Magazine's Intelligencer, landline phones won't be able to benefit from STIR/SHAKEN's reduction in robocalls, meaning you should really only expect to encounter fewer robocalls on your mobile phones.

STIR/SHAKEN Could Cause Your Phone Bill to Increase

Since carriers may have to pay more to set up and maintain the infrastructure necessary for STIR/SHAKEN, your monthly bill could go up. And if your carrier has to pay more for that, it's possible those costs could be reflected in an increased monthly phone bill.