Read more here – https://benchmarks.cisecurity.org/tools2/iphone/CIS_Apple_iOS_7_Benchmark_v1.0.0.pdf
Likewise, this pamphlet provides security recommendations for users of personally managed Apple iPhones and iPads running iOS 5. This refers to a situation in which the user exercises sole administrative control over the device.
Read more here – http://www.nsa.gov/ia/_files/factsheets/iphonetips-image.pdf