美国解密：棱镜计划高清正片

美国解密：棱镜计划8.4

From PBS and Frontline: Last year Edward Snowden downloaded tens of thousands of top-secret documents from a highly secure government computer network. The revelations that followed touched off a fierce debate over the massive surveillance operations conducted by the National Security Agency. Now FRONTLINE investigates the secret history of the unprecedented surveillance progra...