What Is STIR/SHAKEN & How Does It Help Businesses?

January 4, 2024 6 min read

Jeremiah Zerby

Jeremiah Zerby

stir shaken voip technology

How often are you interrupted by robocalls?

It gets tricky to ignore them, especially when they come from legitimate-looking numbers. Some of these calls are genuine, but most are not. Scams that target unsuspecting victims are on the rise.

With Voice over Internet Protocol (VoIP), phone number authentication is a big deal — and it’s only going to get tougher. 

Reputable VoIP service providers, cell phone networks, and the government have teamed up to provide a system for authenticating telephone numbers before someone’s phone rings. 

Authenticating phone calls assures the identity of the originating caller. This technology is known as STIR/SHAKEN. We’ll explain how this protocol works to combat caller ID spoofing and robocalls and how it affects your business communications. 


STIR/SHAKEN is a combination of two acronyms: 

STIR: Secure Telephone Identity Revisited 

SHAKEN: Signature-based Handling of Asserted Information Using ToKEN

STIR/SHAKEN is a framework of protocols used by telephone service providers to authenticate an originating caller’s identity. STIR/SHAKEN solutions are intended to prevent malicious phone calls from being made by unauthorized parties. 

Both originating service providers and terminating service providers verify caller IDs to authenticate callers and avoid fraudulent robocalls. It helps call recipients protect against caller ID spoofing and maintains their trust in the phone service. 

The STIR/SHAKEN framework authenticates VoIP calls using the Session Initiation Protocol (SIP) header to transmit the authentication certificate. 

For legitimate call centers, these standards aren’t hard to meet. But for illegal robocallers, STIR/SHAKEN makes it more difficult to use fake caller ID information. 

Let’s take a deep dive to understand how it works. 

How Does STIR/SHAKEN Work?

The telephone service provider obtains a digital certificate from a certificate authority. These digital certificates work with public key cryptography techniques and are recognized by other service providers. They help in authenticating calls. 

STIR/SHAKEN Diagram: Phone calls are authenticated by a third party to verify the identity of incoming callers. (via Robokiller)
STIR/SHAKEN Diagram: Phone calls are authenticated by a third party to verify the identity of incoming callers. (via Robokiller)

As part of the SIP protocol, STIR uses the telephone service provider’s digital signature to authenticate the caller ID. The calling party sends a SIP invite to their service provider when initiating a call. The service provider verifies the source and calling number to determine the attestation level. 

There are three levels of attestation: 

Did you know? More than one-third of robocalls receive Gateway attestation levels.

Then, the service provider creates an encrypted SIP identity header and sends it to the terminating provider with the SIP invite. The information is taken up by a verification service that authenticates based on multiple factors, including the certificate’s public key, its chain of trust, and various others. 

The terminating provider decides whether to allow or block a call based on attestation levels and other factors per their analytics. 

Types of Scam Calls STIR/SHAKEN Can Mitigate

In essence, STIR is a technology, and SHAKEN is a policy. They work together to authenticate caller IDs and protect against multiple scams, including: 

1. Phishing

Threat actors pose as genuine sources such as banks, credit card companies, or government agencies to trick victims into revealing personal information. They can try to get victims to reveal one-time passwords and other details that can compromise their identity. 

STIR/SHAKEN prevents malicious attempts to spoof caller IDs, safeguarding you against phishing attempts. 

2. Vishing

It’s short for “voice phishing.” Attackers trick targets into giving out sensitive information by impersonating a legitimate professional. They try to retrieve personal information or receive financial payments. 

STIR/SHAKEN allows the phone company to verify if an incoming number is the same as the one on the caller ID. It prevents vishing attempts with digital validation of phone call handoff through complex networks.

3. Tech support scams

Many threat actors impersonate a company’s tech support staff to convince victims of malware in their system. They encourage targets to update the software. While updating, the victim innocently gives away remote access to their computer. 

Attackers leverage this to get the victim’s personal information. Sometimes, they may install malware or ransomware on the victim’s computer. STIR/SHAKEN prevents such incidents by verifying numbers with their caller IDs. 

4. Robocalls

Robocalls are pre-recorded messages that may be legal or malicious. They’re genuine when the calls are about payment reminders, alerts, or incoming calls from legitimate telemarketers.

However, some of these unwanted robocalls are generated by scammers who maliciously engage victims with fake notices such as, “You have violated a traffic law, pay $X in fines to avoid full-scale legal inquiry.” 

Robocalls usually promote scams or sell unwanted products. When attackers spoof the caller ID, it becomes tricky for victims to identify and block such calls. STIR/SHAKEN attests such calls and marks them spam. 

Teams have more space and bandwidth to attend legitimate calls when they can easily recognize spam.

Scams are the highest category of robocalls in 2023 (via Robokiller)
Scams are the highest category of robocalls in 2023 (via Robokiller)

Benefits of STIR/SHAKEN

STIR/SHAKEN differentiates between genuine and spoofed calls to prevent risky telephony experiences. Here are some of its notable benefits:

Why You Should Use Authenticated Numbers for Outbound Dialing

Authenticated business phone numbers help you establish the credibility of your company and deliver the initial trust needed for customers to answer calls. It offers several good things for an organization, such as: 

📈 Increased call answer rates

When you register your caller ID name with the service provider and implement STIR/SHAKEN, it helps customers see that a call is genuine and comes from a legitimate source. Your calls reach customers’ ears instead of going to their voicemail. 

When your caller ID is positive, customers don’t block you permanently. It prevents low attestation ratings and can lead to better sales opportunities and long-term established connections with customers. 

➕ Enhanced brand reputation

You can show your commitment to customers’ security and integrity with authenticated numbers. It helps you make good first impressions as customers believe you’re a trustworthy source and not a scammer trying to impersonate you. 

With your positive brand reputation, customers feel more confident answering their phones without hesitation. Conversely, if your caller ID is inaccurate, consumers may feel you are taking part in shady practices, eroding their trust in your brand. 

✅ Compliance with regulations

Many countries and regulatory bodies are mandating STIR/SHAKEN for outbound calls. Federal Communications Commission (FCC) rules require most providers to implement STIR/SHAKEN on their network IP. 

They require providers to certify in the Robocall Mitigation Database that they have implemented STIR/SHAKEN, as part of the TRACED Act, which stands for Telephone Robocall Abuse Criminal Enforcement and Deterrence.

The law defines the risks and penalties for fraudulent telephone communications.

How STIR/SHAKEN and 10DLC Relate

10-digit Long Codes (10DLC) are local long code numbers approved by local mobile number operators for application-to-person (A2P) messaging. Since they’re pre-approved by phone network operators, businesses avoid any penalties due to non-compliance with messaging regulations. 

A2P 10DLC focuses on SMS authentication, while STIR/SHAKEN concentrates on caller ID authentication. Together, they improve business communications’ security and integrity. 

They complement each other. 10DLC compliance requires businesses to register their brand and campaigns, reducing the possibility of unauthorized communications. STIR/SHAKEN prevents caller ID spoofing, creating a more secure environment for voice communication. 

Is STIR/SHAKEN Mandatory?

Yes, it’s mandatory in the U.S. to implement the protocol from June 30, 2021, for large carriers and June 30, 2022, for smaller and rural carriers. The TRACED Act mandates the implementation of STIR/SHAKEN. 

U.S. consumers alone received over 60 billion robocalls in 2023. With the upward trend of robocalls and call frauds, regulatory bodies in different countries encourage businesses to adopt robust authentication measures within implementation deadlines. 

Recently, the FCC adopted new rules to strengthen its consumer protections, allowing carriers to more aggressively block malicious calls and text messages from noncompliant telephone networks. 

Other countries are making some developments in call authentication while preventing caller ID spoofing. An estimated 25% of all incoming calls on Canadian phone numbers were robocalls in 2021. To combat this,  the U.S. FCC pledged cooperation with Canada in its enforcement efforts. 

Stay Vigilant With Nextiva

After enforcing regulations to mitigate robocalls, there have been some decreases in complaints filed with the Federal Trade Commission. However, they’re still a problem. 

Stay ahead of the STIR/SHAKEN requirements with a fully compliant business VoIP platform from Nextiva. It’s easy to set up, and your team will love its functionality. Plus, you’ll also uphold customer trust in your brand so you can scale your company faster. 

Business VoIP service done right.

Integrate secure phone service, SMS, video, and team chat in ONE platform.

Jeremiah Zerby


Jeremiah Zerby

Jeremiah Zerby is a marketing specialist at Nextiva. He spent three years on the front lines of technical support, troubleshooting internet and VoIP topics. He moved forward into the technical writing and content creation space. He’s helped set up hundreds of businesses and advised thousands of people with their cloud communications.

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