Fixes for Non-Optional Crash and iOS Comp
Fixes for Non-Optional Crash and iOS Comp

[FIX] Converted substr to prefix for iv.
[FIX] Data was not optional, so would crash app on load. Fixed by using a optional check, and default value.

SwiftyBeaver/AES256CBC,SwiftyBeaver/AES256CBC,SwiftyBeaver/AES256CBC