Editor's note: The IAPP is policy neutral. We publish contributed opinion and analysis pieces to enable our members to hear a broad spectrum of views in our domains.
Biometric authentication is increasingly used in daily life from unlocking phones to verifying identity at border control. But as biometric systems grow more pervasive, a key question is being overlooked: What does user control look like when the data is literally part of their body?
Traditional models of consent and data management break down in the biometric context. Most systems are built with a "capture once, use indefinitely" mindset. Consent is often collected in a single moment and rarely revisited. Revocation — the ability for a user to withdraw consent and have their biometric data removed — is either poorly supported or not supported at all.
Biometric systems can be designed in ways that actually honor revocability, not just legally, but technically and operationally and organizations can move from checkbox compliance to building meaningful user control into the fabric of biometric infrastructure.
Unlike passwords, biometric identifiers can't simply be reset. Once a fingerprint or facial scan is compromised, there's no changing it. But even beyond breach risks, users may want to revoke biometric consent for other reasons: a change in trust, a shift in regulation or simply evolving personal boundaries.
The problem is, most systems aren't designed to handle this. Even when users delete their biometric profile, residual traces often remain — in logs, backups, analytics pipelines, or machine learning models. Worse, many systems treat biometric templates as long-lived assets, designed to persist indefinitely for convenience or business efficiency.
This creates a false sense of control. The user clicks "delete," but the data lives on.
To support revocability in biometric systems, a few fundamental assumptions should be reconsidered. First, not all biometric data needs to be stored. For many use cases, on-device matching or ephemeral processing can provide authentication without central storage. Second, consent should not be treated as a one-time checkbox. It should be dynamic and re-evaluated with every data access. Third, deletion must be thorough. True deletion includes removing data from live systems, backups, caches and downstream processors — or at the very least, making users aware of where deletion cannot occur.
Revocation-friendly design is achievable when certain principles are built into system architecture. Start with ephemeral processing wherever possible. Biometric inputs can often be verified and discarded without storage. Make consent a real-time gatekeeper, something that's checked not only at enrollment but also at every point of access. Design biometric templates with revocation in mind: version them, timestamp them, and enable workflows that allow for their secure removal across environments.
Audit logs should be thorough, but also privacy conscious. They should record biometric access events without retaining sensitive inputs themselves. Where biometric data is used to train or fine-tune models, those models should be capable of excluding or minimizing the influence of deleted inputs. Whether through retraining, dynamic forgetting or other strategies, machine learning systems must be part of the revocation plan.
Organizations can start by mapping where biometric data is stored, duplicated or shared. Many don’t realize that biometric traces can live in analytics platforms, debug logs or downstream services. Once mapped, create a deletion workflow that covers all these touchpoints. Shift toward localized, short-lived processing. Build clear documentation and interfaces that show users what data is collected, how it's used and how they can remove it.
Most importantly, change the mindset: treat biometric data as something entrusted to the organization by the user — not owned by the organization. That shift in perspective alone can lead to more thoughtful, privacy-respecting implementations.
The future of biometric systems demands more than one-time consent or static privacy policies. It requires systems that respect change — that adapt when users want to revoke, remove or recover control of their data.
Revocability isn't just about compliance. It's a measure of respect. And in an era where biometrics are replacing passwords, that respect must be embedded in the system itself.
Designing for revocation doesn't diminish the value of biometrics. It enhances trust in the systems that use them. And that trust is the foundation on which responsible identity technology must be built.
Naveen Kumar Reddy Pajjuri is a software engineer specializing in privacy-focused system design.
