[AlexCoventry]

Would that be cryptographically secure? Couldn't someone perturb an RNG based on background radiation by beaming radiation at it?

[ars]

That shouldn't change anything: https://en.wikipedia.org/wiki/Fair_coin#Fair_results_from_a_...

[AlexCoventry]

That argument relies on independent samples, but if someone's beaming radiation at the device to control its output, the samples will not be independent.

[ars]

It's not that easy to control radiation, controlling it to the level of individual decays is not possible.

The closest you can get is bring it closer/further, or shield/unshield.

[AlexCoventry]

I'd rather use a local source in a Faraday cage, so that it's not possible for someone to influence the output at all.

[ars]

A Faraday cage is not going to block this type of radiation.

[gabrielblack]

To test, I made a simple script generating the dispersion graph: the numbers seem to be of good quality