One thing that no one has yet mentioned is:
Your OS and Device security means squat if you are using Facial ID or even fingerprint ID. This is primarily due to the fact that I could easily take your phone, direct it towards you, and unlock it while fleeing with your personal data.
Furthermore, in the United States, any law enforcement agency has the authority to request your fingerprint or use your face ID to examine your phone, and you cannot refuse this request as it is readily available. You are not invoking the Fifth Amendment in this case, as fingerprints and facial recognition fall under physical evidence rather than testimonial evidence. Testimonial evidence refers to the disclosure of knowledge that you possess, which cannot be extracted from you unless you voluntarily recall it; this could include self-incriminating information such as your password.
In 2024 case
United States v. Jeremy Travis Payne US court affirmed that fingerprint is a physical and not testimonial evidence.
So, does this mean biometrics are useless? Absolutely not. It's all about understanding your threat model.
For the 99% Threat (Convenience and Common Theft)
The most common threat to your phone's data is impersonal theft or loss. A pickpocket or someone who finds your lost phone will not have your face or fingerprint. In this scenario, biometrics are an incredibly fast, convenient, and secure way to protect your data from the vast majority of threats. It is far better than having no lock at all or a simple 4-digit PIN.
For the 1% Threat (Targeted Coercion)
For the specific, high-level threats mentioned, being targeted by law enforcement or a determined attacker who has you physically present, a passcode is the ultimate safeguard.
The best practice is to use both. Use biometrics for everyday convenience, but be aware of how to quickly engage Lockdown Mode if you ever feel you are entering a situation where you might be physically or legally compelled to unlock your device.
Lockdown Mode
This is the most critical defense. It is a feature designed to be activated quickly in an emergency. Once enabled, it immediately disables all biometric unlocking methods (Face ID, Fingerprint ID) and requires the passcode or password for access.
On iPhone
You can typically activate it by pressing and holding the side button and one of the volume buttons for a couple of seconds, then tapping the "Lockdown Mode" option.
On Android (like your Pixel)
It can be enabled in the power menu. Once enabled, pressing and holding the power button will show a "Lockdown" option that does the same thing.
Physical vs. Testimonial Evidence
The core of the argument is the distinction the U.S. legal system makes between providing physical evidence (like a key to a lockbox, a DNA sample, or a fingerprint) and providing testimonial evidence (revealing the contents of your mind, like the combination to a safe or a password).
The Fifth Amendment protects you from being compelled to testify against yourself, not from providing physical evidence.
Case Law Precedent
The citation of United States v. Payne (9th Cir. 2024) is correct. In that case, the court affirmed that forcing the defendant to use his thumbprint to unlock a phone was not a violation of his Fifth Amendment rights because it was not a "testimonial" act. It required no cognitive effort or disclosure of knowledge from the defendant's mind.
Circuit Split
It is important to note that this is not universally settled law across all jurisdictions. For instance, in a 2025 case, United States v. Brown, the D.C. Circuit Court reached the opposite conclusion, arguing that compelling a biometric unlock implicitly communicates control and ownership of the device, making it testimonial. However, the precedent set in cases like Payne is the prevailing view in many parts of the country.
Conclusion on the Legal Threat
For the specific threat of being legally compelled by U.S. law enforcement to unlock your device, a strong alphanumeric passcode offers superior Fifth Amendment protection compared to biometrics.
For the vast majority of law-abiding citizens, the scenario of being legally compelled to unlock their phone is a remote, abstract concern.
