For a BTC related project I need to create some addresses on automatic mode; the machine is offline, the machine prints both WiF Key and matching Address, there's minimal interaction for this, so it won't be able to pick much from its own memory in order to generate a good Random seed.
So my idea came about building a small piece of hardware using RDA5807M FM radio module under follow scheme:
Arduino/ESP(32/8266) --> gets/generates pseudo random between 880 ~ 1080, then divides by 10 -> i2c frequency set -> listen 1 second -> 2x 16 bit ADC (capture stereo output) -> sets bytes accordingly ---> repeat the process
At access: return x bytes stored, where x = amount of seed bytes.
RDA5807M is meant to be equipped with a weak or no antenna, in order to get not only music or whatever is being said at that frequency, but also get noise and interference.
A secondary pseudo random may set it to shift the frequency (+0.05 Mhz) or not.
Do you think this solution would provide a good enough Random generator? If not, what/how do you think this can be improved?
I suppose it depends on what attack vectors you're trying to protect against and how vulnerable you'd be if a successful attack were performed, however, the two concerns that immediately come to mind are:
1. If the radio stops working for some reason, you'll possibly be fed a repeating sequence that represents pure silence on all frequencies?
2. An attacker that is aware of your algorithm could potentially transmit a strong enough signal from close enough to your e