On Your Mind

Can authorities compel a suspect to use biometrics to unlock a digital device?

By Pierre Grosdidier

Can authorities compel a suspect to provide a fingerprint or a facial or iris scan to unlock the suspect’s protected digital device?1 This question is increasingly important to law enforcement officials given the growing pervasiveness of biometrically protected smart devices. If the answer is no, a suspected child pornographer might place himself or herself beyond prosecution by protecting his or her stash of contraband with a biometric.

Whereas the Fourth Amendment governs authorities’ ability to seize and search a digital device, the Fifth Amendment’s protection prohibiting self-incrimination controls their ability to compel the device’s owner to surrender access. The Fifth Amendment protects an individual if he or she can show that three conditions are met: (1) compulsion, (2) a testimonial communication or act, and (3) incrimination.2 Authorities usually seek to access confiscated devices when they expect to find child pornography. The first and third elements are easily satisfied in these cases, for obvious reasons. The question then whittles down to whether the act of communicating a biometric is “testimonial.”3

The testimonial aspect of the act of production is different from the substance of the production, which the Fifth Amendment does not protect.4 But, courts have long recognized that the act of producing something might trigger Fifth Amendment protection, as when it requires the individual “to use ‘the contents of his own mind’” like disclosing a safe’s combination.5 Conversely, compelling a suspect to perform a mere physical act, like opening a safe with a key, submitting to a lineup, or providing a blood sample or fingerprints, is not testimonial.6

At least one federal district court has held that the act of compelling a suspect to provide biometrics to unlock a digital device is testimonial. In In re Search of a Residence in Oakland, Cal., the court denied a warrant that sought the right to compel persons found at a search location to provide their biometrics to unlock confiscated devices.7 The court held that if a person cannot be forced to provide a passcode because the act is testimonial, the same logic necessarily applied to a biometric. The court also refused to equate a fingerprint taken for identification purposes with one taken to unlock a phone that contains “a database of someone’s most private information.” It held that the act of pressing a finger to unlock a phone testified to the person’s control over, or connection with, the phone’s contents and was, therefore, protected.8

Most courts have held that compelling a suspect to provide his or her biometrics to unlock digital devices does not offend the Fifth Amendment. These courts reason that the government merely compels a physical act that does not require the suspect to use his or her mind.9 In In re Search Warrant Application for [redacted text], the district judge reversed a magistrate judge who had upheld the Fifth Amendment defense.10 The district judge held that requiring residents of a home to unlock digital devices with their fingerprints did “not qualify as a testimonial communication.” The act of pressing a fingerprint was merely physical and not communicative; it could even be done while the suspect slept. The judge rejected the argument that the ability to unlock a device created the inference that the suspect possessed and controlled the device. Per the opinion, the issue is whether the act is testimonial, not whether it is incriminating because of its consequences.11 For example, taking fingerprints can be highly incriminating but it is not unconstitutional.

Likewise, in In re Search of [Redacted] Washington, D.C., the court held that compelling the use of a subject’s biometric was closer to “the surrender of a safe’s key than its combination,” because no thoughts are required on the suspect’s part.12 The court also could make no “principled distinction” between drawing blood for blood-alcohol content, which is not testimonial, and taking biometric features.13

Two state courts have followed the majority. In State v. Diamond, the Minnesota Supreme Court held that producing a fingerprint was a physical act closer to displaying a body in a lineup than producing documents.14 Similarly, a Virginia trial court held in Commonwealth v. Baustthat compelling a fingerprint to unlock a smartphone was like providing a key and required no mental effort on the part of the suspect.15 TBJ


1. The question of whether authorities can compel a suspect to surrender a passcode will be addressed in a future technology column. The answer is, generally, no, because it is a testimonial act. In re Grand Jury Subpoena Duces Tecum Dated March 25, 2011, 670
F. 3d 1335, 1352 (11th Cir. 2012).
2. United States v. Authement,607 F.2d 1129, 1131 (5th Cir. 1979) (per curiam).
3. See, e.g., In re Search of a Residence in Oakland, Cal., 354 F. Supp. 3d 1010, 1014 (N.D. Cal. 2019).
4. Andresen v. Maryland,427 U.S. 463, 473–74 (1976)(citing Johnson v. United States, 228 U.S. 457, 458 (1913)).
5. In re Grand Jury Subpoena Duces Tecum Dated March 25, 2011, 670 F.3d at 1342, 1345; In re Search of [Redacted] Wash., D.C.,317 F. Supp. 3d 523, 535 (D.D.C. 2018) (mem. op.).
6. In re Grand Jury Subpoena Duces Tecum Dated March 25, 2011, 670 F.3d at 1345 and note 24.
7. 354 F. Supp. 3d 1010, 1013 (N.D. Cal. 2019).
8. Id. at 1016 (citation omitted).
9. In re Search Warrant Application for [Redacted Text], 279 F. Supp. 3d at 800, 804 (N.D. Ill. 2017) (Chang,
D. J.) (mem. op.).
10. Id. at 801.
11. Id. at 805.
12. 317 F. Supp. 3d at 535–36.
13. Id. at 537; see also In re Search of a White Google Pixel 3 XL Cellphone in a Black Incipio Case, No. 1:19-mj-10441, 2019 WL 3401990, --- F. Supp. 3d ---, at *1 (D. Idaho July 26, 2019) (same); United States of Am. v. Warrant, No. 19-mj-71283-VKD-1, 2019 WL 4047615 (N.D. Cal. Aug. 26, 2019) (slip op.) (allowing the compelled use of biometrics under certain conditions).
14. 905 N.W.2d 870, 875 (Minn. 2018) (citing United States v. Hubbell,5 30 U.S. 27, 42–43 (2000) (subpoena for documents)).
15. 89 Va. Cir. 267, 2014 WL 10355635, *4 (Oct. 28, 2014) (not reported in S.E.2d).


This article, which has also been published in Circuits, has been edited and reprinted with permission.

Headshot of Martha NewmanPIERRE GROSDIDIER is an attorney in Houston. He belongs to the first group of attorneys certified in construction law by the Texas Board of Legal Specialization in 2017. Grosdidier’s practice also includes data privacy and unauthorized computer access issues and litigation. Prior to practicing law, he worked in the process control industry. Grosdidier holds a Ph.D. from Caltech and a J.D. from the University of Texas. He is a member of the State Bar of Texas, an AAA Panelist, a registered P.E. in Texas (inactive), a member of the Texas Bar Foundation, a fellow of the American Bar Foundation, and the State Bar of Texas Computer & Technology Section secretary for 2019–2020.

{Back to top}

We use cookies to analyze our traffic and enhance functionality. More Information agree