swift ios 8.0 RSA encryption (known publicKey)

Question

I'm trying to encrypt a string with RSA, I already got a publicKey(String type) from the server. How can I get the secKey without "SecKeyCreateWithData", because this method only supports ios10+ ? But it has to support to ios8.0+.

   if #available(iOS 10.0, *) {
        guard let secKey = SecKeyCreateWithData(data as CFData, attributes, &error) else {
            print(error.debugDescription)
            return nil
        }
    } else {
        //how can I do here?
    }

Answer 1

CoreCrypto and Security is seemingly only supported from iOS 10 onwards (as you've discovered).

You have two options:

1) Generate the RSA components manually, rolling your own implementation (Suggest you avoid this approach).

2) Switch to a modern cross platform crypto library, eg libsodium. (Doesn't support RSA, all EC based for asymmetric crypto).

Apple also have CryptoKit but that doesn't support < iOS 13 .

If you add some extra info about your use-case I will happily suggest further options.