Yeah For P256 We have 1 header byte 32 bytes of x 32 bytes of y 32 bytes of K (private key) Total - 97 bytes For Public key - 65 (without K) The problem is to create from 32 bytes of private key (rawRepresentation) these 97 bytes I found solution with this library Unfortunately counting of KeyPair takes a lot of time But the code is open and it's very cool.

Thank you a lot! It works for me! I had a tab bar controller. When the imagePicker with camera disappeared from the screen, the item from the TabBar was also deleted. You solved it ^_^