Secure communication between Arduino/Esp8266 and server via API?

Question

Arduino

There is an Arduino (enc28j60) / Esp8266 with an RFID card reader and a server with a database, where the numbers of "own" cards are actually stored. How to implement secure data exchange between them, preferably through API get-requests?
An approximate mechanism is as follows: A
card is brought to the module -> Data is read and converted into a string with the card id -> Data is sent to the server via a get-request to the API (naturally encrypted) -> The server decrypts them and looks for such a card in the database -> Depending from this the server responds with an HTTP / JSON / XML response with the result -> Arduino (enc28j60) / Esp8266 lets or not the card.
Each Arduino (enc28j60) / Esp8266 has its own token, with which the server identifies it. It is desirable that it be updated every time it is turned on.

Answer 1

Use Raspberry Pi.