SECURITY guards (at least the good ones) are paid to be paranoid. Computer-security researchers are the same. Many had long suspected that governments use the internet not only to keep tabs on particular targets, but also to snoop on entire populations. But suspicions are not facts. So when newspapers began publishing documents leaked by Edward Snowden, once employed as a contractor by America’s National Security Agency (NSA), the world’s most munificently funded electronic spy agency, those researchers sat up.
