NSA chief envisions 'secure zone' on Internet to guard against attacks

Alexander said the Pentagon would likely have to work with the Department of Homeland Security and the Federal Bureau of Investigations to secure the country's critical infrastructure, 85 percent of which is owned by private companies. He said the agencies may need additional powers to take action during a cyber attack. 

Several pieces of competing cybersecurity legislation pending in Congress would give them that power, but lawmakers have been unable to settle on which agency should regulate civilian cybersecurity. DHS is currently in charge of protecting civilian networks; Alexander said the Pentagon has no role and added that he isn't sure if it should operate domestically unless asked for help.

In his prepared testimony, Alexander defended his dual role as director of the National Security Agency, arguing the agency's resources have been of great value to Cyber Command, as has their co-location at Ft. Meade, Maryland. He emphasized the ability of a single individual to cause outsized harm to an entire nation and described the command as a continuation of previous Pentagon cybersecurity efforts.

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