Silent Security: How passive voice biometrics defends against fraud

By Milind Borkar, Illuma

In a world where fraudsters are constantly evolving their tactics, traditional contact center authentication methods like PINs, passwords, and security questions are no longer enough. Financial institutions and their contact centers need stronger, smarter ways to verify identity – and voice biometrics is stepping in as a key line of defense.

This advanced technology analyzes a person’s unique vocal characteristics to authenticate them quickly and securely. Whether used in an “active” or “passive” mode, voice biometrics is proving to be a powerful tool in the fight against fraud.

Active vs. Passive Voice Biometrics

Before diving into how voice biometrics prevents contact center fraud, it’s important to understand the two primary approaches:

• Active voice biometrics requires the caller to say a specific passphrase (like “My voice is my password”). The system then compares that phrase to a stored voiceprint to confirm identity.
• Passive voice biometrics works in the background, continuously analyzing a caller’s voice during a natural conversation. No passphrase is needed – authentication happens seamlessly and silently.

Both approaches can be effective in stopping fraud, but they serve slightly different purposes and can be even more powerful when combined.

Fighting Fraud With a Voiceprint

Fraud prevention is one of the most compelling use cases for contact center voice biometrics. Here's how it works in practice:

Preventing Account Takeovers

Account takeovers (ATOs) remain one of the most costly and damaging types of fraud. When a criminal uses stolen personal information to impersonate an account holder, traditional verification methods often fall short. Voice biometrics, however, authenticates the person, not just what they know. Even if a fraudster has access to account holder details or answers to security questions, they can’t replicate the voiceprint.

Detecting Deepfakes and Synthetic Speech

As AI-generated voices become more realistic, the risk of synthetic speech attacks has grown. Modern voice biometric systems use “synthetic detection” to identify whether a voice is live and human or pre-recorded and manipulated. These algorithms analyze subtle aspects of machine generated speech that are difficult to cover up, helping organizations stay ahead of deepfake threats.

Real-World Results: IllumaSHIELD™

The impact of IllumaSHIELD passive voice biometrics is both measurable and impressive:

• Mid-Atlantic Federal Credit Union deployed IllumaSHIELD passively in just 1.5 days, achieving an 87% reduction in verification time.
• Wellby Financial enhanced member experience and cut fraud with IllumaSHIELD, achieving a 95% reduction in member verification time. They have deployed IllumaSHIELD across their Contact Center and eBranch teams, with agents using it in 88% of all interactions.
• Empower Federal Credit Union achieved an 81% faster member verification process with IllumaSHIELD, with 8 out of 10 EFCU members choosing to enroll in IllumaSHIELD when offered.

Why Layered Security Matters

Voice biometrics is powerful on its own, but even more effective when used as part of a multi-layered security strategy. Leading fraud prevention solutions combine voice authentication with additional layers such as:

• Risk scoring based on caller behavior
• One-time passcodes (OTPs) for added assurance

Together, these methods create a robust defense that adapts to evolving fraud threats while keeping the experience smooth for legitimate users.

Making the Case for Voice Biometrics

For financial institutions, banks, credit unions, and contact centers, the decision to adopt voice biometrics is more than a technical one – it’s a strategic move to protect both callers and the organization. Benefits include:

• Faster fraud detection and response
• Lower fraud losses and ATO rates
• Improved regulatory compliance
• Better caller experience
• Reduced agent burden and call times

And unlike traditional authentication methods that are easily compromised, voice biometrics is inherently more secure – it’s based on something you are, not something you know or have.

Looking Ahead

As fraud techniques grow more sophisticated, so must the tools designed to stop them. Voice biometrics continues to evolve with enhanced machine learning and AI-driven spoof detection.

It’s clear that the future of authentication will be voice-enabled – not only for convenience but also for security. Organizations that invest in these technologies today are putting themselves ahead of the fraud curve and building greater trust with their members and customers.

Interested in how voice authentication can reduce fraud at your institution? Connect with Illuma to learn more about secure, seamless voice biometric solutions for contact centers.