Tattoos are free speech that we wear on our skin. 

When we look at our tattoos, we may see important milestones in our lives or mistakes that we made in our youth. We may see symbols that represent our ethnic heritage or our pride in our affiliations, such as our military units, church membership, or political ideology. We get tattoos of the musicians and films that have enchanted us, or we memorialize the birth of our children and the family members who have passed away. Some may even get tattoos of our medical conditions in case of an emergency. Our tattoos express who we were, who we are, and who we hope to be.

But when law enforcement looks at our tattoos, they see unique biometric identifiers and a shortcut to learning our personal beliefs and our social connections.

Today, law enforcement generally obtains images of tattoos by photographing detainees during the jail booking process or during prison intake. However, police have been known to collect data on tattoos during routine stops, often using that information to place people in controversial gang databases. In one particularly heinous case, police in San Diego are being sued after officers entered a strip club, detained workers, forced them to pose nude and took photos of their tattoos. 

Traditionally, police have used regular cameras to collect these images and kept the photos in physical albums and text-based databases. Now, law enforcement is pursuing mobile devices and apps that can collect and analyze tattoos instantly. Due to recent advances, current algorithms are able to match tattoos with greater than 90% accuracy. However, algorithms that can accurately connect people based on their tattoos are still in their nascent stages.

That’s where NIST comes in.

In 2014, NIST’s Image Group launched the Tattoo Recognition Technology program, with sponsorship from the FBI’s Biometric Center for Excellence, to conduct experiments to accelerate this technology in the private and academic sectors. 

The first major foray was called the Tattoo Recognition Technology Challenge—Tatt-C for short. NIST and the FBI compiled an “open tattoo database” of 15,000 images—many, if not most collected from prisoners—that formed the basis of NIST’s Tatt-C competition. The data was distributed to 19 organizations—five research institutions, six universities, and eight private companies, including MorphoTrak, one of the largest marketers of biometric technology to law enforcement agencies. The dataset was designed to be the first standardized metric for testing tattoo recognition algorithms.

The Tatt-C competition required participants to perform a series of tests and report their results to NIST, which is part of the U.S. Department of Commerce. These experiments included identifying whether an image contained a tattoo and whether algorithms could match different images of the same tattoo taken over time. The most alarming research involved matching common visual elements between tattoos with operational goal of establishing connections between individuals. 

This summer, NIST plans to launch the next phase: Tattoo Recognition Technology Evaluation, or Tatt-E. These experiments will be conducted internally by NIST using third-party algorithms to analyze an even larger dataset. NIST researchers are hoping to amass a dataset of more than 100,000 images for experimentation that would be collected by the Pinellas County Sheriff’s Department in Florida, the Michigan State Police, and the Tennessee Department of Corrections.

Based on the lack of attention to civil liberties, privacy, and research ethics, EFF believes that Tatt-E should not occur and that NIST’s tattoo recognition research more generally should not move forward without proper oversight.