Biometrics on Trial: How Emerging Technologies Are Shaping Security—and the Courtroom

Introduction

Biometric security, once a topic limited to science fiction or niche industrial applications, has rapidly become an essential part of modern technology. Fingerprint scans unlock our smartphones, facial-recognition systems monitor sensitive facilities, and palm-print authentication grants access to restricted areas. Yet as these systems expand in scope, courts are increasingly tasked with addressing the resultant legal, ethical, and privacy challenges. For patent attorneys who operate at the intersection of law, technology, and business, understanding biometrics is essential. This update on past posts aims to bring patent litigators up to speed on biometric security, clarify ongoing legal controversies, and illustrate how emerging technologies have opened new avenues—and hazards—both in product development and in litigation.

Discussion of Technology

Biometric security uses unique human features —such as fingerprints, facial geometry, or voice patterns—to authenticate an individual’s identity. As highlighted in the earlier posts, traditional security measures like passwords and identification cards remain vulnerable to theft or cloning. Biometric systems, on the other hand, measure properties that are intrinsic to each person. Examples include:

• Fingerprint scanning (common in smartphones)
• Palm vein recognition (e.g., Fujitsu’s PalmSecure)
• Facial recognition (used in both consumer devices and public security systems)
• Iris or retinal scanning (more common in high-security locations)
• Behavioral biometrics, like typing rhythm or gait analysis

The discussion in the original article focused heavily on consumer payment security, referencing Apple Pay’s pioneering combination of fingerprint authentication and Near Field Communication (NFC). Today, industry adoption has proliferated well beyond smartphones. Contactless hand-geometry readers and live-facial recognition gates are being deployed worldwide in airports, corporate offices, and even high-profile sporting venues. In addition to entry-and-exit access, behavioral biometrics—where users’ voice patterns or how they physically interact with a device are tracked—are also gaining traction.

Meanwhile, the legal controversies surrounding biometrics are multiplying just as swiftly as adoption. In Illinois, the Biometric Information Privacy Act (BIPA) has become a focal point for litigation. One high-profile case, Rosenbach v. Six Flags Entertainment Corp. (2019 IL 123186, 129 N.E.3d 1197), discussed whether a plaintiff qualified as an “aggrieved” party under BIPA when the amusement park collected their fingerprint data without proper notice or consent. The Illinois Supreme Court ruled that individuals do not need to show an additional injury beyond the statutory violation itself. This precedent reinforced the importance of careful data-handling procedures for companies that deploy biometric technologies.

Similar scrutiny unfolded in Patel v. Facebook, Inc., 932 F.3d 1264 (9th Cir. 2019), where claimants alleged that Facebook’s facial-recognition tagging feature violated BIPA by storing scans of users’ faces without explicit consent. Although Patel settled after a ruling from the Ninth Circuit Court of Appeals, its implications reverberated: organizations cannot disregard local biometric privacy statutes when developing or deploying face recognition features.

In yet another recent matter, In re TikTok, Inc. Consumer Privacy Litigation, 565 F. Supp. 3d 1076 (N.D. Ill. 2021), plaintiffs sued on grounds that the app’s face-scan features violated both federal and state privacy laws. The resulting settlement underscored that even novel or playful consumer apps face stringent legal obligations once they leverage biometric identifiers.

Advances in Biometrics

Since the original posts were written, new sensor technologies and machine-learning algorithms have improved both the accuracy and consistency of biometric systems. Many of these systems can now accommodate variations that once caused “false negatives,” such as hoarseness in voice recognition or slight scratches on a user’s finger. Also, multi-factor biometric authentication—where two or more biological features are required, such as fingerprint plus iris scan—can dramatically reduce false-positive rates.

However, security threats persist. Sophisticated forgeries of fingerprints or artificially generated facial models can still trick less robust systems. For litigators, this points to critical patent disclosures around how biometric systems detect spoofs, incorporate anti-tampering measures, and protect data. The conversation has shifted from “should we use biometrics?” to “how do we implement biometric solutions in a legally compliant way that preserves user privacy?”

 

Conclusion: Characteristics of a Competent Expert Witness

With the rapid pace of innovation in biometric security comes an equally pressing need for knowledgeable, credible expert witnesses who can address both technical and legal issues. A qualified biometric security expert witness must be able to:

• Explain Complex Technology Clearly. Courts rely on experts to break down specialized technology into understandable terms. An adept witness will help judges and juries understand how a fingerprint scanner or iris-recognition system functions at the hardware and software levels.
• Stay Current with Evolving Standards. From new sensor types to advanced machine-learning methods, biometrics is constantly evolving. An expert must stay abreast of not only the engineering parts of emerging systems but also the relevant data-protection and privacy statutes, especially as they differ from one jurisdiction to another.
• Maintain Scientific Rigor and Objectivity. Effective testimony often demands reproducible demonstrations, clear references to peer-reviewed literature, and a transparent method that meets the Daubert standard. The expert must be perceived as fair, basing conclusions on product specifications, forensic examination, and recognized scientific principles.
• Leverage Knowledge of Case Law. As shown by Rosenbach, Patel, and the TikTok litigations, a well-informed expert witness will integrate case-specific facts into the broader legal landscape, making clear how the contested biometric system aligns (or conflicts) with precedent and local privacy statutes.
• Bridge Patent Law and Technology. Finally, an expert in biometric security for patent litigation must articulate how functional elements (e.g., how a sensor processes images or voice inputs) interact with claims of novelty, non-obviousness, and infringement. The witness’s ability to read patent claims, map them to an accused system, and address prior art can prove pivotal in a court’s analysis.

By blending technical knowledge with strong communication skills, an expert witness in biometric security is capable of illuminating the underlying science for courts and patent litigators alike. Whether the dispute involves potential infringement of core biometric patents or alleged privacy violations under statutes like BIPA, a knowledgeable professional can synthesize evidence, explain complex system architectures, and trace the flow of data—from user enrollment to authentication.

As biometrics continues to expand, so too does the volume of litigation. Anyone involved in patent and privacy disputes should note that the complexity of these technologies demands nuanced understanding and rigorous legal strategies. Armed with up-to-date knowledge, professionals who testify on biometric security can make sure courts and juries grasp both the intricacies of the technology and the policies meant to protect our most personal data.