CCDigestXXX functions are not public API for iOS

[SergejJurecko]

Because this functions are used, this library can not be used in a published iOS app. App store rejects it for using private APIs.

[malept]

So this should be noted in the API docs, I guess. Would you like to create a pull request?

[SergejJurecko]

I would prefer to switch to CC_XXX functions and limit pbkdf2 to macOS only. Would you be ok with that?

[malept]

That would also work. I would appreciate it if the docs mentioned this as well though.

[malept]

Sorry, I think I misread. Are you proposing to change Hasher to use the CC_* instead? If so, I think that it would be better if there was a separate impl for iOS (see how crypto-hash is architected).