Social secrets

Remember “metadata”? When news organizations began disclosing documents in June leaked by former National Security Agency contractor Edward J. Snowden, Americans learned their government was logging their daily phone calls—not necessarily eavesdropping on conversations but cataloging so-called metadata like phone numbers, call length, and location coordinates.

Late in September, The New York Times reported how the NSA uses phone and email metadata to map the social networks of “foreign intelligence targets,” as revealed by other Snowden documents. If the NSA wants to learn about a foreigner in the course of a national security investigation, it can legally build a digital phone book of the person’s contacts—even if it includes Americans. As long as a U.S. citizen or legal resident is not the primary suspect, no warrant is needed.

If that sounds benign, consider what a log of your own phone calls and emails might reveal about you: Frequent contact with doctors, friends, politicians, and advocacy or religious organizations could reveal your apparent physical or mental health, personal associations, politics, or religious convictions. This information would be admittedly useful for discovering networks of terrorism or Muslim extremism, but Americans who make frequent contact with Muslim nations—employees of a Christian aid organization, for example, or U.S.-based journalists—could also be swept up in such a net. The NSA calls it a “contact chain.”

The U.S. intelligence community has not always viewed the mapping of social networks without a warrant as legal. According to the Times, NSA officials decided in November 2010 that the practice would be lawful under a precedent set by a 1979 Supreme Court decision. The policy change was not reviewed by the Foreign Intelligence Surveillance Court, which is normally responsible for overseeing such programs.

However, William Binney, a former NSA employee-turned-whistleblower, says the agency was mapping the social networks as early as 2001. Binney helped develop an early program called ThinThread that collected internet data for terrorism investigations. But he left the agency in October 2001, he told me, after learning analysts were collecting phone and email metadata from Americans. He claims the agency has “graphs”—social network maps—for the entire U.S. population: “They also do it for everyone in the world they can get their hands on.”

Eight million dollar man

Zac Vawter’s right leg is a mechanistic marvel: Made of aluminum, it has a computer, two motors, and 13 sensors to measure movement or pressure, and weighs less than his left leg. For Vawter, who lost the bottom half of his right leg in 2009 after a motorcycle accident, walking comes as easy as thinking.

Too bad he’s not allowed to take the leg home just yet. The bionic leg is part of a project at the Rehabilitation Institute of Chicago, funded by about $8 million from the Defense Department. Electrodes fitted to Vawter’s right thigh sense muscle movements associated with walking or bending an ankle, and read his intention to bend an ankle, walk, or climb stairs.

The smart leg, according to a September report in the New England Journal of Medicine, cuts falls and unnatural movements nearly in half, compared to regular prosthetics. —D.J.D.