Split the difference

摘要

The US National Security Agency's Prism program seems to be lifting personal data from the internet. How? Internet giants including Google and Facebook strongly deny that the NSA has direct access to its servers. There is another way, however. A slide from an internal NSA Powerpoint presentation suggests the agency is siphoning directly from fibre-optic cables. To do this, it probably uses "splitters", which split the light beam.