Feature Request: Encryption capabilities

[jsbrich]

Have you considered adding some sort of encryption to the data stream? I realize it is a wired connection, but I'm thinking of scenarios where one MCU is in a secure location and the other isn't, such as a keypad outside and an access controller inside. Or are you aware of any existing libraries that could be added to work with yours?

[franky47]

That's a very interesting request. I'm not very familiar with encryption implementations on embedded devices, so I wouldn't be able to recommend a particular one. As for ciphers, AES or ChaCha20 for symmetric encryption would be good starting points, or X25519-ChaCha20 for public-key encryption of data to exfiltrate from the device.

Though your keypad use-case would probably need some form of trusted execution / secure enclave on the unsafe side, as we may assume an attacker be able to extract key material from the controller ROM/RAM or perform side-channel attacks.

Actually, I had another use-case the other day that may intersect with yours, which was to use a different transport than Serial.

It could be possible to change the API to accept a generic stream to write data to / read data from, which could then be just a plain hardware serial interface, or a custom transport, or an encryption middleware.

Edit: this stream API is actually already implemented, it's a matter of specifying the Serde class against anything that conforms to the Arduino Stream API (read, write, available, etc).