I hope the next revision of MAVLink (one of the most common message serialization/transport protocols used for UAVs) will have built-in encryption.
While systems can encrypt MAVLink messages in transit, I have not seen it actually done- everyone is relying on security of the physical layer (i.e. obscurity of telemetry radio frequency hopping/channel negotiation, WiFi security).
So in most implementations, MAVLink messages are actually transmitted in plaintext, over plain TCP/UDP connections.
While systems can encrypt MAVLink messages in transit, I have not seen it actually done- everyone is relying on security of the physical layer (i.e. obscurity of telemetry radio frequency hopping/channel negotiation, WiFi security).
So in most implementations, MAVLink messages are actually transmitted in plaintext, over plain TCP/UDP connections.