@Bas: Not trying to be overly snarky or to be a Microsoft apologist, but you're doing a significant port of code from one runtime to another and are getting only 16 errors and you're complaining ?
That said, some of these would seem to be critical things to leave out. There's probably some alternative APIs that for whatever reason are considered better and should be used now is my guess. The cryptography APIs fall in this category, because I can't see them not including something there. Time to start digging and figuring out where the differences lie and what the options are.