Why do you want to check for differences by comparing the crc instead of the actual data? 200 bytes is not much data I only have 4 bytes of spare radio payload in this application. I physically can't send it due to outside constraints such as distance to receiver, and small battery capacity limiting the total number of transmissions per 15 year lifespan. Certain settings can changed frequently, and I need to way to ensure that the device is in the expected state. CRC was what I initially came up with, but maybe a hash or some other totally random thing might be better by some measures?