Asked by @HulaHoop:
Whonix-devel - randomsound questions
randomsound developer replied to the mailing list:
(But somehow the reply does not (yet) show up on the mailing list archive.)
From: Daniel Silverstone
On Sat, Nov 23, 2019 at 20:29:48 +0000, firstname.lastname@example.org wrote:
Hi Dan. I’m a privacy distro dev and we are thinking of including
randomsound as an entropy source by default.
I’d recommend against that, reasoning below…
- Does it gather entropy at all times when a soundcard is connected or only when there is sound playing?
It was designed to gather sound at all times it was running.
- I assume form the package description it relies on sound output and not microphone input unlike van Heusden’s audio-entropyd
It was meant to use an input line, microphone or line-in.
- How well can it function in a virtual environment?
Probably not usefully at all.
Randomsound was written a long time ago when computer hardware was simpler and less careful in terms of sound design. It was common for sound cards to be fairly (a) electrically noisy and (b) configurable. As such, I had a server which had need of entropy and a sound device which had no microphone or line-in device attached, and a sound card which could decouple its level monitoring from any controls (leave it floating) – this combination gave me a source of electrical and thermal noise I could harvest.
These days sound cards have mandatory filtering and are sufficiently complex that I would not like to make any assertions about an ability to set one up in the manner I recommended for use with randomsound. Virtual devices are even more controlled and thus even less likely to provide access to the kinds of entropy randomsound attempted to harvest.
These days I’d recommend ensuring that host systems harvest entropy from as many sources as possible, optionally sharing them around among themselves (I believe there’s software for this kind of thing) and then qemu has a virtio-rng device which allows transfer of entropy from host to guest (at a controlled rate).
There are also devices one can purchase which can increase the available entropy pool if your hosts are regularly running dry. For example the chaoskey by Keith Packard and Bdale Garbee.
Good luck with your quest for entropy, and thank you all for taking privacy so seriously.
Daniel Silverstone http://www.digital-scurf.org/
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