NSA's information behemoth to swallow a library a minute

If anyone still doubts the formidable reach of the US National Security Agency, a quick drive into the Utah hinterland outside Salt Lake City should convince them otherwise.

Deep in Mormon country, thousands of labourers have worked for two years to build a US$1.7 billion facility that will provide a new home for the NSA's exponentially expanding information store. Sited on an unused swath of a National Guard base, by September it will employ about 200 technicians, span 93,000 square metres and use 65 megawatts of power.

The NSA says the centre will not illegally eavesdrop on Americans, but is otherwise vague. Its scale is not in doubt. Since January 2011, a reported 10,000 labourers have built four big halls filled with servers and cables plus a vast space for technical support and administration. Generators and huge fuel and water tanks will make the site self-sustaining in an emergency.

Outside experts disagree on the centre's potential. Some say it will just store data; others envisage a capacity to analyse and break codes, potentially enabling technicians to snoop on the entire population.

William Binney, a mathematician who worked at the NSA for almost 40 years and helped automate its worldwide eavesdropping, said the computers could store data at the rate of 20 terabytes - the equivalent of the US Library of Congress - per minute. "Technically it's not that complicated," he said. "You just need to work out an indexing scheme."

Binney, who left the agency in 2001 and blew the whistle on its domestic spying, said the centre could absorb and store data for hundreds of years and allow agencies such as the FBI to use the information retroactively.

He said the centre would probably have spare capacity for "brute force attacks"- using speed and data hoards to detect patterns and break encrypted messages in the so-called deep web where governments, corporations and other organisations keep secrets. There would be no distinction between domestic and foreign targets. "It makes no difference any more to them," Binney said.