Nice to see that you are Swift-ifying crypto functionality with the new Apple CryptoKit ( https://developer.apple.com/documentation/cryptokit ).

But please add support for the Elliptic Curve `secp256k1` used by Bitcoin and many other projects. Cryptocurrencies are increasing in popularity and many developers currently rely on C-libraries being wrapped in ObjC being wrapped in Swift. These solutions are bad for developers and bad for users.

For the sake of the safety of the users and convenience for developers (and the ability to sleep at night).

Also please add support for common export/import methods for keys.