What is caller authentication?

Caller authentication is a system that verifies the identity of people who call your contact centers. After verification, customers can access services and sensitive information. Caller authentication prevents malicious actors from gaining access to customer accounts.

Caller authentication methods can be passive or active. These methods include multi-factor authentication (MFA), one-time passwords (OTP), and biometrics.

What is call verify?

Call verify is a feature included in many phone solutions, such as business VoIP. The feature helps you identify whether calls are from legitimate sources.

For your business, this means you know customers are calling from real phone numbers and the locations you expect. Call verify flags suspicious calls. It detects call spoofing, where scammers fake a call from a customer's phone number.

Call verification can also help consumers know if a call from a business is legitimate.

What is caller ID verification?

Caller identity verification is similar to call verify, but it has a more specific purpose. When calling someone using a caller ID, you can verify the trustworthiness of the caller ID with the help of telecom providers and business communications apps that handle this verification process in the background.

Technologies such as STIR/SHAKEN (a set of technology standards used to combat caller ID spoofing in telephone networks, especially in the U.S. and Canada) can assess the call for spoofing or manipulation. Once approved, they attach a digital certificate, which confirms that the phone call is legitimate and that it corresponds to the appropriate caller ID.

What is contact center authentication?

Contact center authentication verifies the identity of customers during support interactions. Authentication typically requires multiple steps, with various types of verification.

Anti-spoofing checks, such as caller ID verification, are common security measures. Another layer is often knowledge-based authentication (KBA). Other techniques include OTPs and behavioral analysis for fraud detection.

What is IVR caller authentication?

IVR caller authentication is the verification of callers using an automated phone system. Businesses often use an interactive voice response (IVR) system to automate call routing. The preconfigured menu system authenticates callers. It then grants them access to sensitive information, such as account balances or PINs.

IVR caller authentication is commonly used in contact centers. It's often found in financial services, healthcare, and other industries.

Why caller ID authentication matters 

The world is becoming more digital every day. New tech has given customers greater flexibility and enabled businesses to better connect with their audiences.

With any new technology, scammers and hackers seek out new vulnerabilities. They use social engineering techniques, such as phishing, to gain access to customer accounts. In the Phishing Activity Trend Report, it was found that there were over 930,000 phishing attacks in the third quarter of 2024.

Scammers often find personally identifiable information (PII) on social media networks. AI and machine learning (ML) have also made it easier for cybercriminals to use deepfakes, as these can bypass customer identification processes.

There are many potential threats and back doors, so caller ID authentication is critical to protecting your customers and your bottom line.

A caller authentication system has many benefits, including:

• Improved customer experience (CX): Passive authentication works without requiring any user actions. Streamlined active authentication processes help maintain a smooth CX.

• Increased customer confidence: Caller ID authentication reassures customers that their account is protected. Customers are more confident and loyal, and they engage more with your company's products and services.

• Enhanced security: Authentication methods add extra security layers. These protect your business and its customers from increasingly sophisticated attacks.

• Better compliance: Better protection ensures you can mitigate and minimize risk. Caller ID authentication streamlines compliance with regulations such as HIPAA or the GDPR.

• Greater efficiency: It's easier for your business to verify identities and authenticate calls. The system empowers your agents to spend less time on verification and more time on call resolution.

Types of caller authentication methods

An effective caller authentication strategy can make the entire process appear simple. However, there’s nothing simple about it. You’ll need to implement several verification and identification methods to deter cybercriminals. You also want to instill customers with confidence, but also not frustrate them with complicated hoops to jump through.

Before you can start the caller verification balancing act, you need to understand the methods available.

Multi-factor authentication (MFA)

Multi-factor authentication requires more than one unique factor to verify someone’s identity. When using two forms of verification, it’s known as two-factor authentication (2FA). MFA is normally used when logging into online bank accounts or accessing health records.

What are the multiple factors used to authenticate a customer?

• OTP: One of the most common MFA methods is to send a one-time password as an SMS text or email to the customer. Without access to either option, the user is unable to verify their identity.

• Something you know: Customers can select predetermined questions and answers, such as “What was the name of your first pet?”

• PIN: An additional factor can be as simple as a personal identification number. This requires scammers to gain two different pieces of information to gain access.

Platforms like Vonage offer silent authentication, an improved 2FA user experience that doesn’t require additional customer input (no OTPs), along with stronger security for the business.

MFA isn’t only for your customers. It’s also a great way to secure your business operations. A 2024 JumpCloud Survey found that 83% of IT professionals require employees to use MFA to access system resources.

ANI matching and validation

ANI stands for automatic number identification. It’s a telecommunications technique that streamlines phone number validation for contact centers.

Much like caller ID, an ANI tool identifies an inbound phone number. An extra step is taken to verify whether the number displayed matches a phone number in a database of known customer numbers.

If a customer calls from an unusual phone number, such as a number from a payphone, this would alert the system of a potential scammer. ANI verifies known numbers so your team can start resolving issues right away.

Knowledge-based authentication (KBA)

Knowledge-based authentication uses information only the customer should know to verify their identity. This type of authentication falls strictly under the “something you know” category mentioned above.

Security questions that involve a mother’s maiden name, place of birth, or name of a pet are only one type of KBA. You can also tailor questions to the business. For example, financial institutions often use loan amounts or credit card details for verification.

KBA usually falls into one of two categories:

• Static KBA: This involves predetermined questions and answers that customers encounter when creating user accounts.

• Dynamic KBA: This involves real-time and changing information, such as transaction history or previous address. Dynamic authentication adds a higher level of security. An example question would be, “From which retailer did you make a purchase of $__.__ on [date]?”

Biometric authentication

Biometric authentication relies on a customer’s unique biological identifiers for security purposes. These identifiers include fingerprints, facial recognition, and voice patterns. Unlike OTP and KBA, biometric identifiers can’t be gleaned, stolen, or guessed. They are extremely difficult to falsify.

One call center authentication method is biometric authentication. Biometric software automatically verifies customers as they speak, providing a frictionless, passive form of ongoing authentication.

What happens when people reach out on other channels? Mobile apps can use facial recognition with smartphone cameras, or even fingerprinting.

Token-based authentication

Token-based authentication requires customers to use a token to verify their identity. The token is a unique piece of data, usually given to the user ahead of time. This could be a fob or smart card with a unique identifier.

Businesses can also require customers to use authenticator apps. These generate time-sensitive and dynamic tokens. Users log into an account and consult the app to verify their identity with a unique code.

A similar method to token-based authentication is known as flash calling. A short call is made to the customer’s registered phone number to verify their identity, without them needing to do anything. The system then verifies that the number and device are active.

How does caller authentication work?

Caller authentication requires additional knowledge and actions from users. The complexity of the process and the effort needed depend on what verification methods you use. In general, caller ID authentication is either passive or active.

Passive authentication

Passive authentication is mostly handled in the background. This type of authentication involves seamless verification processes that require minimal actions from the customer. Some types of passive authentication include ANI and biometric voice authentication.

Active authentication

Active authentication requires customers to take direct action. Identification and validation only occur once the user has satisfied the requirements. Multi-factor authentication works in this way, requiring OTPs or something the customer knows.

Token-based authentication is another example of active authentication. After the user verifies their identity, they’re given a unique access token that grants them access to the relevant account.

What is the caller authentication process?

The global cloud-based contact center market is anticipated to grow from $26.70 billion in 2024 to $147.10 billion by 2034, at a CAGR of 14.27% during the forecast period. You may be like one of the many organizations investing in business communications, and, for you, caller authentication is critical. However, it's vital to understand the authentication process before choosing a verification system.

Initiation

When someone reaches out to your contact center team, an auto-attendant or IVR system greets them. In some cases, they may get straight through to an agent. During initiation, some authentication takes place, such as ANI matching and validation. At this stage, the user's number is compared against customer records.

Verification

After initiation, the automated system or support team member begins the verification process. Now is when active and passive verification methods come into play. This includes knowledge-based authentication, OTP, and voice recognition.

Approval or denial

Once the verification data has been submitted, the system or agent cross-references it with records on file. Active authentication methods, such as MFA, are handled by the system with little to no effort from a contact center team member.

At this point, the identity verification is either approved or denied. If access is granted, the interaction moves forward as usual.

If the customer is unable to authenticate, several things can happen. First, they are notified of the denial. Next, you can allow them to reattempt or use an alternative method.

For example, instead of an OTP sent to an email, they can try to answer a security question. If authentication is fully automated, you can escalate denials to live agents, who can implement dynamic KBA or other methods for verification.

Implementing a caller authentication process

Caller authentication is integral to the security of your business and its customers. You want to tailor the specifics to meet the needs of your industry and operations. How do you implement a caller authentication process for your organization? Follow this basic roadmap.

Assess your current system

The first place to start is to evaluate your current system. What works well, and where are you introducing the most risk? What types of data do you handle? Identify gaps in your process so you know what threats you need to safeguard against.

What about the CX? Gather feedback from customer satisfaction (CSAT) surveys and monitor metrics like customer effort score (CES). This will give you a better understanding of how to maintain a balance between ease and security. 

Choose the right authentication method

Next, choose the right authentication method or methods for your contact center. The primary factor to consider is the nature of your business.

Are you handling financial accounts or processing ecommerce orders? Scammers can only do so much damage with the latter, while they can cause maximum losses with the former.

Does your customer base expect a simple authentication process or robust and rigorous security steps? Refer to your feedback data. Evaluate the available authentication methods. Choose which ones satisfy security needs and maintain customer expectations. 

Integrate authentication solutions

Once you know how to balance the caller authentication equation, it’s time to choose the right tools. Find solutions that readily integrate with your existing system. What security apps integrate with your current contact center platform?

You may find it’s time to update to a modern cloud-based contact center. These services often come with enterprise-grade fraud detection, anti-spam, and call spoofing identification.

AI-powered solutions like Vonage also come with 2FA and branded calling to raise consumer trust. Our Number Verification API adds effortless, passive authentication to your system. 

Challenges and risks of caller authentication

Caller authentication offers greater security. It minimizes risks from fraud and account seizures. It’s not all smooth sailing when you implement an identification and verification system. Caller authentication comes with its own set of challenges and risks.

• User experience impacts: Caller authentication means you introduce more complexity to your IVR system. You’re asking more of your customers. It's more difficult for them to reach your support team or access information. Disabled consumers may find it burdensome to navigate your authentication checks.

• Security oversights and limitations: An authentication system can cause complacency with IT security. Your team still needs to be diligent and alert at all times. Many verification methods, such as KBA, can be bypassed with social engineering techniques.

• Data privacy compliance: Sensitive information, such as biometric data, requires tight controls. You'll also need to maintain compliance despite handling higher volumes of customer data.

• New risks: Scammers gain new ways to impersonate customers every day. Malicious or careless employees can cause additional damage due to greater PII being available.

• Costs: Implementing and maintaining an authentication process requires more resources. Your IT team needs to stay on top of evolving technologies and changing cybercriminal methods.

• Technical complexity: Integrating authentication tools with your existing system introduces more variables. These require more resources. Authentication also creates more processes for your team to monitor and troubleshoot.

Caller authentication best practices

Implementing an effective caller authentication system doesn’t just happen by accident. You need to assess your situation and make an action plan. You can save yourself from having to go back to the drawing board by following caller authentication best practices.

Use a layered security approach 

A single authentication method often is not enough to mitigate risk and prevent fraud. Use a layered approach to add redundancies and address multiple threat types.

For example, ANI matching can be the first line of defense. Support that with either KBA questions, OTPs, AI-powered voice recognition, or a combination of the three. The more layers you add, the less likely a customer account will be compromised.

Focus on employee training

Train your team to understand how to implement your authentication processes. Make sure they understand how passive authentication works. They also need to know what’s required on their part for active authentication methods.

Use role playing to teach agents how to recognize questionable behavior and when to escalate to a supervisor.

Leverage data encryption

Data encryption adds yet another security layer to your authentication system. 

Your basic approach protects against call spoofing, deepfakes, and other possible impostor techniques. However, hackers may still intercept and hijack calls after verification. Many contact center solutions offer AES-256 encryption to protect data during an interaction.

Robust password management

Customer education is critical to any authentication strategy. Set requirements that passwords should be at least 12 characters long and have a combination of letters, numbers, and special characters.

Prompt customers to change passwords regularly and avoid repeating them. Incorporate a list of popular and commonly used passwords, and ban customers from using these phrases during password creation.

Monitor, analyze, and improve

Caller authentication isn’t a mountain you can summit. Instead, it's a moving goalpost. Monitor your system for effectiveness by tracking metrics like average authentication time, fraud detection rate, and failure rate. Also, track customer feedback KPIs, such as CES.

Analyze what the data is telling you, and make improvements when necessary. Schedule regular tests and simulations to check for potential system vulnerabilities.

Choose the right software

Save yourself time and money by choosing the right software on the first try. Use contact center management, business communication, and IT security tools to meet your needs.

Things to look for include:

• Flexibility: How compatible is the software with your existing business tools? Go with flexible options that connect to popular platforms.

• Robust security and compliance: Choose tools that use the most up-to-date security technology. These will be fully compliant, meeting industry standards and certifications for data protection.

• Scalability: Only use solutions that can scale with business growth and customer demand. Otherwise, you’ll have to scrap everything and start all over again later down the line.

• Cost: Don’t skimp on customer data protection. Go with an option that delivers value and fits your budget.

What features should the best call center authentication solutions of 2025 include?

When choosing the right call center or contact center authentication software, you want to ensure you have the best features. When it comes to call center caller authentication, you need capabilities that mitigate risk both now and in the future.

Features to look for in a call center solution in 2025 include:

• Multi-factor authentication: 2FA, OTPs, and other MFA options are stalwart security measures for any authentication strategy.

• Passwordless authentication: Token-based authentication, ANI matching, and biometric voice recognition create a seamless customer support experience.

• VoIP Caller ID management: Support caller ID from mobile and VoIP phone calls so you can always identify customers regardless of how they contact your support team.

• Branded calling: Add logos and your brand name to caller ID during outgoing calls to improve customer trust and recognition.

• AI-powered features: AI and machine learning (ML) power capabilities like voice and speech recognition. Besides authentication purposes, these technologies can analyze caller emotions and make conversational insights. The AI also picks keywords to assist agents with call resolution.

• Security and compliance: Look for certifications like SOC 2 Type 2 and PCI DSS compliance for sufficient data protection. Look for compliance with relevant regulations, such as HIPAA.

• User-friendly: Opt for tools that build a seamless contact center experience. These include features such as AI-powered virtual assistants and IVR menus.

Future trends in call authentication solutions

No one can know for sure where the future of authentication solutions will go. However, one thing for certain is AI will continue to make a significant impact. Statista reports that GenAI improved contact center agent productivity by 15% last year. Automating workflows is becoming a standard, so it’s likely AI will become central to authentication and fraud detection in the future.

Biometric authentication, such as voice recognition, will make the experience easier for customers. In a 2024 survey by Statista, almost 30% of respondents cited biometrics as the most secure authentication method.

Unique biometric identifiers may eventually eliminate the need for passwords and security questions. However, security technology needs to keep up with advancing deepfake technology to stay one step ahead of threats.

Secure the future with the best caller authentication solution

Secure customer account data by opting for a caller authentication solution like Vonage. Our platform comes with a user-friendly Fraud Defender (2FA), adding an extra layer of security.

Stay updated with what’s happening through real-time monitoring and alerts, as well as receiving notifications of suspicious activity for both SMS and voice traffic.

Not all of your customers reach out by phone, so our service protects your omnichannel contact center authentication over WhatsApp and email. A silent authentication feature can seamlessly verify users with minimal effort. Customers can create passwords and PINs for their preferred channels.

Learn more about Vonage Verify API.