rf encryptions
First you need to determine the throughput of the data required. Then determine the data format and the encryption method (package format). The total data includes the original data you want to send, the encoding overhead for the signal source, the channel encoding overhead for overcoming the channel noise. The high speed data usually requires high performance MCUs, better MCUs are needed if burst mode is expected. Find a matched microcontroller with 50% redundant capability, typically. Another thing is to find good transmitters and good PHY datalink devices at both sides. Good luck!