With B4A I can do everything except games and (still) RSA en-/decryption with my server.
Ok, here you go:
In B4A: Encrypt a string with a RSA 4096 Bit (yep, there's an Encryption lib which does it). Then send the encrypted string to a php script (no prob).
In PHP: Decrypt that string, do something, send back another string which is Encrypted the same way. I know the basics and I can create Keys via OpenSSL, but I'm struggling how to use them in b4a/php (padding, utf8, etc.).
Would be very nice if someone could provide a simple "step by step" example.