In an interview with NBC News, Edward Snowden said that the NSA can take over your phone even when it's off. It sounds paranoid, but it's possible. Here's one way to defend your phone against privacy-invading malware. This video gives you step-by-step instructions for booting your iPhone in DFU mode.
The superspying agency is facing lawsuits over surveillance it conducted on just about everyone, and it's being asked to hand over information. But the NSA says it can't, because its system is too complex to stop it from deleting its own data. A judge had ruled that the NSA had to preserve data under Section 702 of the Amendments Act to the Foreign Intelligence Surveillance Act.