The US is to come under a cyber attack on Tuesday as part of a test of the national infrastructure.
The Cyber Shockwave exercise will involve a huge simulated attack against US government and business national infrastructure systems.
The attack is being run by the Bipartisan Policy Center's National Security Preparedness Group.
Former Department of Homeland Security secretary Michael Chertoff and former CIA deputy director John McLaughlin will take the roles of government leaders in a mock-up of the White House Situation Room in Washington.
The test will examine the command and control capabilities of the US while under cyber attack, and determine how quickly countermeasures can be deployed and backup systems activated.
Chertoff and McLaughlin will also formulate on-the-spot advice for President Obama.
Unusually for such a drill, the entire event will be open to public scrutiny. Highlights will be shown on the Government News Network, and the press will be given access to the Situation Room itself.
The test is part financed by companies including PayPal, SMobile Systems and General Dynamics.
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