The password was supposed to die years ago, and biometrics were supposed to kill it. In large part they have: fingerprints unlock phones, faces authorise payments and irises speed passengers through airports. Signing in with something you are, rather than something you remember, feels effortless — which is precisely why the security questions now being asked about biometric logins deserve attention before the technology becomes completely unavoidable.
The central problem is simple to state. A password can be changed after a breach; a face cannot. As biometric templates accumulate in databases held by employers, services and governments, researchers and regulators are asking what happens when those templates leak, how consent works when a login is effectively compulsory, and what fallbacks remain for people whose biometrics fail. Our homepage reporting and Tech News coverage examine the debate.
You Cannot Reissue a Fingerprint
Modern systems rarely store a photograph of a fingerprint or face. Instead they store a mathematical template, often processed on the device itself, and compare fresh scans against it. That design limits the damage from many breaches, but it is not universal: centralised systems, older databases and poorly built applications still hold data that researchers have shown can sometimes be reverse-engineered or replayed. Presentation attacks — printed fingerprints, masks, recorded voices, increasingly deepfakes — form a second front in the same arms race.
Security specialists therefore argue biometrics should be treated as a strong username, not a complete secret, and combined with other factors for sensitive actions. Studies surveyed by Nature on spoofing and liveness detection underline the point: the scan is only as trustworthy as the system’s ability to confirm a living person is present and that the surrounding device has not been compromised.
Consent, Exclusion and the Fallback Problem
Biometrics also fail unevenly. Manual workers’ fingerprints wear smooth, some disabilities prevent standard scans, and face-recognition systems have documented accuracy differences across age and ethnicity. When a biometric gate has no dignified alternative — a PIN, a staffed desk, a human review — exclusion becomes a design flaw with real consequences for banking, benefits and travel. Several regulators now insist that a non-biometric route must exist and must not be deliberately miserable to use.
Consent is thornier still. Employees asked to clock in by face scan, or tenants asked to enter their building by fingerprint, are not in a position to refuse freely. Privacy law in many jurisdictions treats biometric identifiers as sensitive data deserving special protection, and enforcement actions against employers and landlords have begun to test where convenience ends and coercion begins.
Using Biometrics Well
None of this means abandoning a technology that has genuinely reduced account takeovers compared with weak passwords. The emerging good practice is specific: process and store templates on the user’s device where possible, require liveness checks, add a second factor for high-value transactions, publish a clear fallback, and delete templates promptly when accounts close. Passkeys, which pair device biometrics with cryptographic keys that never leave the device, embody much of that thinking.
For individuals, the sensible habits are equally concrete. Register biometrics only on devices you control, keep a strong PIN as well, and be wary of services that demand a face scan without explaining storage and deletion. The face you log in with is yours for life; it is worth asking who else gets to keep a copy, and for how long. Designers of authentication systems increasingly describe their goal as invisibility with accountability: a login that feels effortless to the legitimate user, resists imitation by everyone else, and leaves a clear record when something about the attempt looks wrong. Standards bodies are now codifying those expectations into testing regimes that vendors must pass before large buyers will consider their systems at all.
