The Chinese government has a national policy of economic espionage in cyberspace. In fact, the Chinese are the world’s most active and persistent practitioners of cyber espionage today. The bottom line is this: China has a massive, inexpensive work force ravenous for economic growth. It is much more efficient for the Chinese to steal innovations and intellectual property—the source code of advanced economies—than to incur the cost and time of creating their own.
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Michael Chertoff, Mike McConnell, William Lynn - former Secretary of Homeland Security, former Director of National Intelligence, former Deputy Secretary of Defense, respectively
really interesting read here