Here is an article on security agencies using a private amazon cloud system built at the governments spying facility in Utah. http://www.nextgov.com/cloud-computing/2014/11/nsa-turns-clo.... So it is possible Amazon can secure it properly.

"NSA officials picked up on Google research in 2007 that ultimately paved the way for the intelligence agency’s formal adoption of cloud computing in 2010—part of a broad effort within the intelligence community to more effectively share data and services. In a similar move, the CIA last year signed a contract with Amazon Web Services for a cloud to be used by all 17 intelligence agencies."