4 ms·

This was mentioned somewhere on the site and it is abandoned but it seems like a great way to get some entropy also. From a software radio dongle. https://gith

This was mentioned somewhere on the site and it is abandoned but it seems like a great way to get some entropy also. From a software radio dongle. https://github.com/pwarren/rtl-entropy https://github.com/pwarren/rtl-entropy

genewitch 4y ago
I've used randio and rtl-entropy, and they work okay, but there's some - possibly legitimate - concerns that even a shielded device can be made to output arbitrary [enough] bits from a concentrated attack, should an adversary know you're using that for entropy. As far as generation, old webcams sealed inside of coffee cans painted as dark as possible on the inside, and then sealed to ensure no light gets in, can be used to generate bits pretty quickly. I haven't had time or inclination to mess with avalanching diodes/transistors/resistors to verify the randomness and immunity to environment, but i have used the above methods to test their entropy, and used it to generate One Time Pads. As per my HN profile, i used to be very into entropy research and methods; but lately my home - and homestead - life take up most of my time. and RDRAND et al use thermals from the dark silicon to generate ~1mhz of entropy (as of 2018,) which should be sufficient for practically any normal usage of entropy. A hardware entropy / RNG should only be needed if you are running something like a "lottery", you still need a verifiable "whitener", and you never touch "CSRNG" or "PRNG" anywhere.
- tonetheman 4y ago
  Your comment is super interesting. I did not know you could get entropy from a dark web cam. Super cool stuff!
  - genewitch 4y ago
    as Joachim mentioned; and as i thought i replied already - all sensors have enough noise to be entropy sources. If you can quiesce a sensor - by putting it in a chamber that reduces whatever it senses, or otherwise reducing the input, you can grab "noise". MEMS sensors are notorious for being "noisy", and should always be looked at for cheap entropy sources. Followed by webcams in black chambers, webcams with a single photon source in a reflective chamber, anything that can pick up any RF whatsoever (including ADCs with signal and a resistor or inductor to ground), and so on up to thermals, Geiger detectors, avalanche silicon circuits, and beyond.
  - JoachimS 4y ago
    Most sensors have internal noise that can be extracted. I've extracted entropy from biometric sensors by turning of noise suppression.

genewitch 4y ago

I've used randio and rtl-entropy, and they work okay, but there's some - possibly legitimate - concerns that even a shielded device can be made to output arbitrary [enough] bits from a concentrated attack, should an adversary know you're using that for entropy. As far as generation, old webcams sealed inside of coffee cans painted as dark as possible on the inside, and then sealed to ensure no light gets in, can be used to generate bits pretty quickly. I haven't had time or inclination to mess with avalanching diodes/transistors/resistors to verify the randomness and immunity to environment, but i have used the above methods to test their entropy, and used it to generate One Time Pads. As per my HN profile, i used to be very into entropy research and methods; but lately my home - and homestead - life take up most of my time. and RDRAND et al use thermals from the dark silicon to generate ~1mhz of entropy (as of 2018,) which should be sufficient for practically any normal usage of entropy. A hardware entropy / RNG should only be needed if you are running something like a "lottery", you still need a verifiable "whitener", and you never touch "CSRNG" or "PRNG" anywhere.

tonetheman 4y ago
Your comment is super interesting. I did not know you could get entropy from a dark web cam. Super cool stuff!
- genewitch 4y ago
  as Joachim mentioned; and as i thought i replied already - all sensors have enough noise to be entropy sources. If you can quiesce a sensor - by putting it in a chamber that reduces whatever it senses, or otherwise reducing the input, you can grab "noise". MEMS sensors are notorious for being "noisy", and should always be looked at for cheap entropy sources. Followed by webcams in black chambers, webcams with a single photon source in a reflective chamber, anything that can pick up any RF whatsoever (including ADCs with signal and a resistor or inductor to ground), and so on up to thermals, Geiger detectors, avalanche silicon circuits, and beyond.
- JoachimS 4y ago
  Most sensors have internal noise that can be extracted. I've extracted entropy from biometric sensors by turning of noise suppression.