Senator Al Franken (D-MN) has spoken out against a Google Glass app that uses facial recognition to identify strangers. Yesterday, Franken published an open letter to the makers of NameTag, an app meant to match people's faces with photos from social media accounts or other online sources. "Unlike other biometric identifiers such as iris scans and fingerprints, facial recognition is designed to operate at a distance, without the knowledge or consent of the person being identified," he wrote. "Individuals cannot reasonably prevent themselves from being identified by cameras that could be anywhere — on a lamppost across the street, attached to an unmanned aerial vehicle, or, now, integrated into the eyewear of a stranger. "

Because of Google's across-the-board ban on facial recognition, NameTag isn't an officially sanctioned Google Glass app. Nonetheless, it's currently available in beta, and the claims on its website are sweeping. "NameTag can spot a face using Google Glass' camera, send it wirelessly to a server, compare it to millions of records and in seconds return a match complete with a name, additional photos and social media profiles," says the description. Right now, it appears to work with social media accounts, but the company behind it says it's also working on a system to scan profiles from dating sites and criminal databases like the National Sex Offender Registry.

We haven't tried the app, so it's not clear how well this actually works — the experimental nature of Glass lends itself to apps that promise a lot more than they can reasonably deliver. Creator Kevin Alan Tussy, though, seem to hope for exactly the kind of system Franken fears. "A user can simply glance at someone nearby and instantly see that person's name, occupation and even visit their Facebook, Instagram or Twitter profiles in real-time," the site says.

Tussy's flavor quote nears self-parody: "I believe that this will make online dating and offline social interactions much safer and give us a far better understanding of the people around us ... It's much easier to meet interesting new people when we can simply look at someone, see their Facebook, review their LinkedIn page or maybe even see their dating site profile." In what's sure to become the app's slogan, NameTag "can make the big, anonymous world we live in as friendly as a small town."

The text is ambiguous what level of consent the system will need: if it only matches against a database of people who have signed up, that's much less of a privacy issue. Tussy promises that the app will offer privacy safeguards, but what he suggests sounds like an opt-out system that will let people log in to NameTag and prevent their profiles from being shown. Franken, however, is attempting to clear up these questions, asking where the company scans for records, whether it will use an opt-in system, and how its developers plan to prevent stalkers or hackers from abusing the app.

Franken has previously written Apple to raise privacy concerns with the iPhone's Touch ID system, and as chair of the Senate Subcommittee on Privacy, Technology and the Law, he's well-placed to create a legal framework for facial recognition on something like Glass. Today, the executive National Telecommunications and Information Administration will also begin work on creating such a framework with the help of industry groups and privacy experts. "I strongly urge you to postpone the launch of NameTag until the NTIA completes its study and best practices for this technology are established," Franken tells NameTag.