The Obama administration is going ahead with a controversial plan to have the National Security Agency screen government email and other official computer traffic passing over private networks.

The plan is part of a cybersecurity initiative launched by the Bush administration in 2008 and known as Einstein 3. The purpose of the program is to protect government computer systems from attack, and the Department of Homeland Security insists that only data going in and out of government systems will be subject to special screening for malicious code.