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Facial Recognition Technology, Face ID and the Constitution

Facial Recognition Technology and the Constitution

Facial recognition technology, once a figment of science fiction movie producer imagination, is now a reality, and continues to become more and more a fact of our daily lives. Apple executives recently announced that iPhone owners will have a new method to unlock their phones. Those who purchase the soon to be released iPhone X will be able to access their phones using a new feature called Face ID. Instead of scanning a fingerprint to unlock a phone, the iPhone X owner can scan her face to unlock it.[1]

Like Touch ID before it, Face ID raises privacy concerns about compelled unlocking if an individual who owns the phone is detained by police.[2] Can a police officer force someone who has been arrested to unlock her phone with her face, so that law enforcement may access its data?

The United States Supreme Court has established a layer of legal protection for cell phone owners by holding that a police officer must obtain a search warrant to search a cell phone.[3] In Riley v. California,[4] police stopped David Riley for a traffic violation and then arrested him on a weapons charge.[5] During a police search incident to the arrest, an officer seized a cell phone from his pants pocket and investigators examined the phone’s contents.[6] They found photographs of a car that had been involved in a shooting a few weeks earlier and these photos were admitted into evidence at his trial.[7] Riley was convicted and sentenced to fifteen years in prison.

Riley argued that police had violated his rights under the the Fourth Amendment, which provides that “people shall be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures…[8] The Supreme Court unanimously agreed, finding that the search violated Riley’s Fourth Amendment rights. The court held that prior to conducting a search of the data on a phone, officers must secure a warrant. The Court reasoned that the content of people’s phones is inherently private, going so far as to observe that phones contain “the privacies of life.”[9]

Applying the legal principles established in that case to Face ID, is apparent that the Fourth Amendment protects a person from being required to use Face ID to allow police to access her phone without a warrant. At most, police may be able to seize the phone and hold it until a warrant to search it can be obtained, if police were otherwise allowed to search the person on other grounds. For example, a person being lawfully arrested may be constitutionally searched even without a warrant.[10] Assuming there is reason to believe that evidence or fruits of illegal activity are on a phone found during a legal search, the police may seize the phone and hold it. They can then apply for a warrant to search the phone and, once received, execute the search.

Even with a warrant, however, the inquiry regarding Face ID does not end. While the warrant to search the phone satisfies the Fourth Amendment’s warrant requirement, there are additional considerations under the Fifth Amendment.   

The Fifth Amendment protects the right to remain silent and protects the right to avoid self-incrimination. It states: “No person shall…be compelled in any criminal case to be a witness against himself…[11] Even a search warrant does not give the police the authority to force someone to incriminate himself. On the contrary, the “Miranda” warnings that must be given to arrested suspects before questioning are required to inform the defendant of his right to remain silent.

Thus, the question becomes: Is unlocking a phone using facial recognition tantamount to self-incrimination? If so, a search warrant would give no authority to force a person to use facial recognition in this capacity. This question is “emerging in importance as access to…cellular phones advances”[12] and has come before multiple state courts.

In Commonwealth v. Baust, the defendant was suspected of strangling his girlfriend. Police detectives believed that a video of the assault may have been on his cellphone.[13] Even with a search warrant, the defense argued, the defendant could not be required to give police information that would lead to them being able to access his phone.   The Virginia Circuit Court found that the defendant could not be compelled to tell police his passcode to his phone, but the police could compel him to provide a fingerprint.[14]

The court cited other cases, a including Supreme Court case, to establish that the Fifth Amendment protects against requiring a defendant to give evidence that is “testimonial,” but not evidence that is documentary. Evidence is testimonial if conceding its existence and authenticity tends to incriminate. Forcing a defendant to reveal a passcode requires the defendant to communicate knowledge, unlike production of documents, fingerprints or even voice samples (since the importance of a voice sample is its physical characteristics rather than its content). The password is not known “outside of the defendant’s mind.” [15] A fingerprint, on the other hand, is not testimonial and can be compelled, similarly to the way police can force a defendant to provide a blood or other DNA samples pursuant to a valid warrant.

Three years later, in State v. Diamond, the Minnesota Court of Appeals similarly concluded that compelling a person to place a finger on a phone does not amount to a Fifth Amendment violation.[16] The court reasoned that providing by providing his fingerprint to unlock his phone, Diamond did not have “to disclose any knowledge he might have or to speak his guilt.”[17]

Though these decisions indicate that the government can compel a person to produce his fingerprint to unlock a phone because it’s not testimonial, the Fifth Amendment remains “a very unsettled area” according to Brett Max Kaufman, a staff attorney at the ACLU’s Center for Democracy.[18] Kaufman has argued that using a fingerprint to unlock a phone is testimonial under the Fifth Amendment because a person is “transforming the information” and doing it “with a translation that’s his own.”[19] Another attorney, Andrew Crocker of the Electronic Frontier Foundation, has called the use of fingerprints to unlock phones a “clever-end-run” around by law enforcement of constitutional rights.[20]

Some legal scholars argue that the Fifth Amendment issues presented by Face ID will be the same as they are for Touch ID, which were at issue in the Baust and Diamond cases. Professor Jeffrey Welty at the University of North Carolina argues that the two are equivalent. As such, officers will be able to compel a person to unlock her phone with Face ID recognition with a warrant. Welty says, “Standing there while a law enforcement officer holds a phone up to your face or your eye is not a ‘testimonial’ act, because it doesn’t require the suspect to provide any information that is inside his or her mind.”[21]

The Center for Digital Democracy, a privacy advocacy group, has stood at the forefront of analyzing technological advances and determining how these may impact Americans for nearly 20 years. At a recent conference discussing Face ID’s legal significance, the group posed the question, “Where do we stop? Have we thought through the implications?”[22] Though technology companies may not have evaluated all the constitutional implications, lawyers, law professors, and judges will grapple with them for the foreseeable future.  


[3] Id.

[5] Riley v. California, 134 S. Ct. 2473, (2014).

[6] Id.

[7] Id.

[8] U.S. Const. amend. IV.

[9] Boyd v. United States, 116 U.S. 616, (1865).

[10] Chimel v. California, 395 U.S. 752 (1969)

[11] U.S. Const. amend. V.

[12] Kristen Vogl, “Isearch into the Iphone,” 20 J. Tech. L. & Pol'y 179, (2015).

[13] Commonwealth v. Baust, 89 Va. Cir. 267, (2014).

[15] United States v. Kirschner, 823 F. Supp. 2d 665, (2010).

[19] Id.

[22] Supra Note 18.