German Chancellor Angela Merkel and President Obama in September at the G20 summit in Russia. She and other leaders have objected after hearing that the NSA was listening to their phone calls. Anton Denisov/Host photo agency/Getty Images hide caption

itoggle caption Anton Denisov/Host photo agency/Getty Images

News of U.S. surveillance in Europe has met with distrust and anger; officials are heading to Washington to discuss matters next week. Here, members of an artists' group paint a mural called "Surveillance of the Fittest" on a wall in Cologne, Germany, on Thursday. Frank Augstein/AP hide caption

itoggle caption Frank Augstein/AP

Massive government surveillance of Americans' phone and Internet activity is drawing protests from civil liberties groups, but major legal obstacles stand in the way of any full-blown court hearing on the practice. Among them: government claims that national security secrets will be revealed if the cases are allowed to proceed. Patrick Semansky/AP hide caption

itoggle caption Patrick Semansky/AP

U.S. Ambassador to France Charles Rivkin (in red tie) leaves the Foreign Ministry in Paris after being summoned Monday following reports that the National Security Agency spied on French citizens. Thibault Camus/AP hide caption

itoggle caption Thibault Camus/AP

A scan of the printed SSL key handed over by Lavabit owner Ladar Levison. U.S. District Court for the Eastern District of Virginia hide caption

itoggle caption U.S. District Court for the Eastern District of Virginia

Edward Snowden, seen here in a photo provided by The Guardian, is a finalist for the Sakharov Prize. Earlier this year, Snowden leaked classified information about secret U.S. surveillance programs. AP hide caption

itoggle caption AP