In 2024 alone, global telecom carriers blocked or labeled over 50 billion spam and scam calls, according to major call-analytics providers. While these protections are essential for consumers, they’ve created a growing problem for legitimate businesses: even compliant, real calls are increasingly flagged as “Spam Likely” or blocked entirely. As a result, trust in voice communication has eroded to the point where more than half of incoming calls now go unanswered.

This surge in robocalls and caller-ID spoofing isn’t just an inconvenience, it’s a direct threat to business communication, customer trust, and regulatory compliance. To address this crisis, regulators and telecom carriers introduced STIR/SHAKEN. Rather than relying on surface-level caller ID data, STIR/SHAKEN uses cryptographic verification to determine whether a call can be trusted.

Today, secure and authenticated calling is essential. Therefore, it is critical for businesses to understand that STIR/SHAKEN directly impacts whether calls are answered, ignored, or blocked and whether a company’s name appears on a customer’s screen or is replaced with a warning label. This article explains STIR/SHAKEN in clear, practical terms, breaks down how attestation levels work, and shows why proper business setup is the foundation of trusted, compliant, and successful calling in the modern telecom ecosystem.

What Is STIR/SHAKEN? 

STIR/SHAKEN is a caller-authentication framework designed to stop caller ID spoofing and fraudulent robocalls by verifying that a phone call actually originates from the number it claims to come from.

It operates at the carrier network level, not as an app or software you install. Instead, it uses cryptographic identity verification to authenticate calls as they move through the public telephone network.

At its core, STIR/SHAKEN helps carriers answer one critical question for every call:

“Can this caller be trusted?”

If that trust cannot be established, the call is more likely to be labeled “Spam Likely,” “Scam,” or blocked before it ever reaches the recipient.

Breaking Down the Acronyms

1. STIR — Secure Telephone Identity Revisited

STIR is a set of Internet Engineering Task Force (IETF) standards that defines how a call’s identity is digitally signed at the point of origination.

When a call is placed, the originating service provider attaches a digital certificate of identity to the call using SIP (Session Initiation Protocol). This certificate cryptographically asserts that the caller is authorized to use the originating phone number.

The terminating carrier can then verify this certificate to confirm:

• The call has not been spoofed
• The caller’s identity has not been altered in transit
• The originating provider vouches for the caller

In simple terms: STIR creates a verifiable chain of trust for the call.

1. SHAKEN — Signature-based Handling of Asserted Information Using toKENs

SHAKEN is the operational framework that defines how carriers interpret, validate, and act on STIR identity information, particularly across complex and mixed telephony environments.

While STIR was originally designed for IP-based (VoIP) networks, much of the global phone infrastructure still relies on legacy, non-VoIP systems. SHAKEN bridges this gap.

Developed jointly by the SIP Forum and ATIS (Alliance for Telecommunications Industry Solutions), SHAKEN ensures that STIR’s identity authentication can function across:

• VoIP networks
• Legacy TDM systems
• Interconnected carrier environments

SHAKEN also establishes the rules for what happens when identity information is missing, incomplete, or unverifiable, allowing carriers to decide whether to trust, label, or block a call.

Why STIR/SHAKEN Matters for Modern Business Communication

Caller ID spoofing has evolved from a consumer nuisance into a serious business risk. Fraudulent actors manipulate phone numbers, and the consequences are real: T-Mobile reports that almost half a billion scam robocalls are made each week, resulting in an estimated $30 billion in losses for users in the U.S. alone.  In response, carriers have tightened filtering systems, and unfortunately, legitimate businesses are often caught in the crossfire.

The result is a growing trust deficit. Even valid business calls are increasingly ignored, mislabeled, or blocked altogether. Reduced answer rates, damaged brand credibility, and disrupted customer journeys have become common challenges for organizations that rely on outbound calling.

STIR/SHAKEN was introduced to address this breakdown in trust at its root. Rather than depending on number reputation or post-call reporting, STIR/SHAKEN authenticates calls at the network level, using cryptographic verification to confirm that a call truly originates from an authorized source. This authentication gives carriers the confidence to deliver calls correctly and provides end users with stronger assurance that the call is legitimate.

Research by Transaction Network Services (TNS) reinforces the importance of this approach, showing that clear call authentication signals have the greatest impact on reducing fraud engagement and improving call trust. When users recognize that a call is verified, they are significantly more likely to answer and engage.

For organizations that depend on outbound communication such as call centers, sales teams, customer support departments, and financial services, STIR/SHAKEN has shifted from a regulatory requirement to an operational necessity. Proper implementation helps prevent “Spam Likely” labeling, improves call completion rates, and protects long-term brand reputation. More importantly, it ensures that critical business calls reach real customers, preserving trust, compliance, and professional credibility in an increasingly skeptical call environment.

How STIR/SHAKEN Works (Step-by-Step)

At its core, STIR/SHAKEN works in three critical steps. The entire workflow happens in milliseconds, but the outcome directly affects whether a call is answered, ignored, or blocked.

Step 1: Call Origination & Identity Attestation

When a business places an outbound call, the originating voice service provider (carrier) first evaluates the caller’s identity. This assessment results in an attestation level, which reflects how confidently the carrier can verify both the caller and their right to use the displayed number.

There are three attestation levels that influence call success under STIR/SHAKEN:

• A-Level Attestation: Full Trust (The Gold Standard)

Level A attestation indicates the highest degree of confidence. It means:

• The business is a verified legal entity
• The calling number is owned or explicitly authorized
• The carrier fully trusts the caller’s identity

Impact:

Calls are far more likely to display the company name correctly, avoid spam labels, and achieve higher answer rates.

• B-Level Attestation: Partial Trust

With Level B attestation:

• The carrier recognizes the business
• But cannot fully validate number ownership or authorization

Impact:

Calls typically go through, but may display generic labels or lack verified branding.

• C-Level Attestation (Minimal Trust)

Level C applies when:

• Caller identity cannot be confidently established
• Number authorization is unclear or missing

Impact:

Calls face a high probability of being labeled “Spam Likely,” marked as “Unknown Caller,” or blocked entirely.

This attestation decision is the most critical moment in the STIR/SHAKEN process. It sets the foundation for how the call will be treated downstream.

Step 2: Digital Signing & Caller ID Authentication

Once the attestation level is assigned, the originating carrier uses STIR (Secure Telephone Identity Revisited) to digitally sign the call. This involves attaching a cryptographic certificate to the call signaling:

• Who is making the call
• Whether they are authorized to use the number
• How much trust the carrier places in the caller

This digital signature travels with the call across carrier networks and cannot be altered without detection. Importantly, this process does not slow down call delivery, it occurs in real time at the protocol level.

Step 3: Call Verification at Termination

When the call reaches the recipient’s carrier, SHAKEN (Signature-based Handling of Asserted Information Using toKENs) comes into play. The terminating carrier validates the digital signature against trusted certificate authorities.

Based on the verification result, the carrier decides how the call is presented to the end user. Outcomes typically include:

• Displaying the verified business name
• Delivering the call with a neutral or generic label
• Flagging the call as “Spam Likely”, “Scam”, or “Likely A Business”
• Routing the call to voicemail or blocking it entirely

This final verification step determines whether the call is perceived as trustworthy or suspicious by both the carrier and the recipient.

Why a Legal LLC Structure Is the First Step to Level A Attestation

Here’s what many businesses overlook: STIR/SHAKEN is rooted in legal identity, not just technology.

Carriers can only grant Level A attestation when they have full confidence in “who you are” and “your right to use a phone number”. That confidence starts with having a registered legal business entity, such as an LLC or corporation, supported by clear and consistent documentation.

Without a formal legal structure, things quickly fall apart:

• CNAM registrations fail or remain incomplete
• Business name verification becomes inconsistent
• Attestation levels drop from A to B or C
• Calls are more likely to be labeled or filtered

That’s why caller ID issues are often legal and data problems disguised as technical ones. A verified LLC creates a single, authoritative source of truth that carriers, call-analytics systems, and caller ID apps can reliably trust. When your legal identity is clear and consistent, Level A attestation becomes achievable, and your calls regain credibility.

Implementing STIR/SHAKEN: What Businesses Need to Know

Adopting STIR/SHAKEN doesn’t have to be complex, but it does require the right setup and the right partners. Here’s what the process typically looks like for businesses.

1. Choose a STIR/SHAKEN–Compliant Provider

The first step is working with a telecom or VoIP provider that fully supports STIR/SHAKEN. A capable provider like LikelyABusiness.com  should manage the entire authentication flow, from verifying your business identity to digitally signing outbound calls and validating incoming ones. This ensures compliance happens at the network level, not as a manual workaround.

2. Prepare to Verify Your Business Identity

To assign higher attestation levels, your provider must confirm who you are and validate your right to use the phone numbers you’re calling from. This usually involves submitting basic business documentation and completing an identity verification process. The clearer and more complete this information is, the stronger your call authentication will be.

3. Rely on Your Provider for Certificate Management

STIR/SHAKEN relies on cryptographic certificates that act as digital credentials for your calls. These certificates are issued and governed by trusted authorities, and in most cases, your provider handles this entirely on your behalf. Your role is simply to ensure your provider is authorized and properly configured to manage them.

4. Monitor Call Trust and Reputation

An effective STIR/SHAKEN implementation doesn’t stop at setup. Leading providers offer visibility into how your calls are being authenticated, labeled, and delivered. Access to dashboards, reporting tools, and alerts allows businesses to monitor call trust, identify potential issues early, and maintain a strong calling reputation over time.

The Benefits of STIR/SHAKEN for Businesses and Consumers

STIR/SHAKEN plays a critical role in restoring trust in voice communication. By verifying caller identity at the network level, it protects consumers from fraud while helping legitimate businesses reach their audiences without interference.

1. Stronger Protection Against Fraud and Scam Calls

One of the primary benefits of STIR/SHAKEN is its ability to combat caller ID spoofing. By cryptographically verifying the origin of a call, the framework makes it extremely difficult for malicious actors to impersonate trusted numbers. This significantly reduces scam attempts and helps limit financial and identity-related fraud.

2. Restoring Trust in Voice Communication

Years of robocalls and spoofed numbers have trained consumers to ignore unknown calls. STIR/SHAKEN helps reverse this behavior by ensuring that verified calls display accurate caller information. When people see authenticated calls, they are far more likely to answer and engage.

3. Improved Call Deliverability for Businesses

For legitimate businesses, call authentication directly impacts performance. STIR/SHAKEN reduces the risk of calls being labeled as “Spam Likely,” sent to voicemail, or blocked altogether. Verified calls have higher answer rates, which is essential for sales teams, support centers, and customer outreach operations.

4. Regulatory Compliance and Risk Reduction

STIR/SHAKEN is not just a best practice, it is increasingly a regulatory requirement. Adopting the framework helps businesses stay compliant with government and carrier mandates, reducing the risk of penalties, service disruptions, or reputation damage due to non-compliance.

5. Better Customer Experience and Brand Confidence

When customers receive authenticated calls, conversations start with confidence rather than skepticism. Clear caller identity improves the overall experience, strengthens brand credibility, and fosters more productive interactions between businesses and their customers.

Future of STIR/SHAKEN and Evolving Standards

STIR/SHAKEN was a pivotal step in restoring trust in voice communication, but it is far from a finished technology. As call authentication becomes more widespread, the framework itself is evolving to handle new use cases, improve transparency, and expand beyond its original scope.

1. Expansion Beyond Domestic Networks

Currently, STIR/SHAKEN is broadly implemented in the United States and Canada, with carriers signing and verifying billions of calls per day under the framework. However, global adoption remains uneven, and calls that traverse international networks can lose authentication signals when they pass through regions without STIR/SHAKEN support. Ongoing industry efforts aim to extend these protections to international calls, closing gaps in cross-border caller verification and strengthening global trust mechanisms. 

1. Rich Call Data (RCD): The Next Frontier

One of the most notable innovations on the horizon is Rich Call Data (RCD), an extension of the STIR/SHAKEN framework that allows additional authenticated information to accompany a call. Unlike traditional caller ID, which relies on potentially inconsistent third-party databases, RCD can deliver data such as the caller’s verified name, brand logo, and call purpose directly from the originating organization. This enhanced data travels with the call as part of the authenticated identity token, making it difficult to spoof while increasing call transparency and user trust. 

Notably, T-Mobile and its partners completed the first standards-based wireless call combining authenticated caller ID and Rich Call Data. It demonstrates the practical potential of RCD to help users instantly recognize not just who is calling, but why. This marks a key milestone toward enhanced caller experiences and stronger enterprise trust signals. 

1. Branded Calling and Identity Trust

Closely related to RCD are emerging concepts around Branded Caller ID or enhanced authentication that display verified brand elements on the recipient’s device. When fully standardized, these enhancements will allow businesses to attach authenticated metadata like logos or call reasons to their calls, significantly improving engagement and reducing missed connections. This technological direction builds on STIR/SHAKEN’s core principles while amplifying its value for enterprise communication and customer trust. 

1. Ongoing Standardization and Industry Collaboration

Technical experts continue refining the protocols behind STIR/SHAKEN. Working groups within the Internet Engineering Task Force (IETF) and telecommunications alliances are pushing forward extensions to PASSporT tokens that protect rich metadata and align authentication with broader identity claims. These standards advances aim to ensure that authenticated call information remains secure and accurate as it travels across diverse network environments. 

How Likely A Business Ensures Accurate Caller ID and Trusted Call Delivery

Likely A Business focuses on solving the real-world problem businesses face today: calls being mislabeled, ignored, or blocked due to identity and reputation issues. As a professional caller ID correction service, Likely A Business helps businesses verify, correct, and stabilize how their numbers appear across carriers and caller-ID platforms.

With Likely A Business, businesses can ensure that:

• Caller identity data is accurate and consistent across major carriers, CNAM databases, and analytics providers.
• STIR/SHAKEN alignment is properly supported, reducing the risk of downgraded attestation or spam labeling.
• Carrier-level discrepancies and legacy records are identified and corrected before they impact call delivery.
• Regulatory expectations around caller transparency and authentication are met without guesswork.
• Reputation issues are detected early, preventing lost calls, lost leads, and damaged trust.

By proactively auditing number reputation and correcting caller-ID data at the source, we help businesses ensure their calls reach customers clearly labeled, trusted, and uninterrupted. 

Final Thoughts

STIR/SHAKEN has evolved beyond a compliance checkbox into a defining factor for whether legitimate business calls are trusted, delivered, or blocked. As regulatory oversight increases and carriers apply stricter call-filtering logic, incomplete or poorly aligned caller authentication now carries real operational consequences. Unverified calls are far more likely to be mislabeled, ignored, or stopped before they ever reach a customer.

The key lesson is that successful STIR/SHAKEN adoption requires more than basic implementation. Accurate caller identity data, a properly established legal entity, and consistent authentication signals across carriers and analytics systems are all critical. When these elements are misaligned, even technically compliant calls can lose credibility at the network level.

This is where expert intervention becomes essential. Likely A Business works at the source of caller trust issues, helping organizations resolve identity mismatches, correct CNAM records, establish STIR/SHAKEN compliant business setup, and address legacy data problems that weaken attestation. The outcome is improved call delivery, stronger brand recognition, and higher answer rates.

Thus, in an environment where phone trust is fragile and skepticism is high, STIR/SHAKEN is not just beneficial; it is foundational to modern business communication.

Ready to fix your caller ID and protect your call reputation?