William Binney, a 32-year veteran of the National Security Agency who helped design the top-secret program revealed by whistle blower Edward Snowden, describes how his former agency built the massive system that tracks, monitors and records phone and Internet communications of U.S. citizens. Binney resigned from the National Security Agency in 2001 to protest growing domestic surveillance. He was a senior NSA crypto-mathematician largely responsible for automating the agency’s worldwide eavesdropping network. He was one of the two co-founders of the agency’s Signals Intelligence Automation Research Center. He resigned after the Sept. 11 attacks.