> This article seems to be talking about using quantum effects for random number generation.
> The devices you point to use the semiconductor avalanche effect (http://en.wikipedia.org/wiki/Avalanche_breakdown) which is a thermal effect.
> > Most noise is quantum noise (including the one quoted, even though electron avalanche is a classic phenomenon, in semiconductors it's going to have quantum effects)
> > But in the end it doesn't matter, any unpredictable, non manipulable source of randomness is fine. Other sources of noise in electrical circuits (apart from quantum noise origins) are interference (like the 60Hz hum, radio interference, and even background radiation)
And being in a semiconductor it is a quantum process (in fact most sources of noise in circuits are quantum in origin - not that it matters)
And do you think quantum effects are not affected by temperature? REALLY?!
Zener avalanche noise is unpredictable. How is an attacker supposed to guess when the next electron/hole pair is going to be created in the depletion region? Physically, what happens is the emitter-base junction is reverse biased, turning it into a diode that is blocking current from flowing from the emitter to the base. Every once in a while, due to thermal noise and likely quantum effects, an electron jumps up a valence level, creating an electron/hole pair in the middle of the reversed-biased N/P junction, where there is a strong electric field. This launches the electron in one direction and the hole in the other, where they gain speed rapidly. The electron has higher mobility and will gain enough speed to bang into other electron/hole pairs, creating an avalanche of electrons.
There is no known way for anyone to guess when the next avalanche will occur, or how large it will be, so long as there is no outside signal controlling this effect. Implemented poorly, it can just put out power supply noise, and not true unpredictable entropy. Implemented well, it is a solid, reliable, cheap, and fast entropy source. It is absolutely critical that a zener noise TRNG has an open auditable design!
As for "quantum" effects, I consider that marketing fluff. What we need is provable, reliable unpredictability, not some radioactive decay or photon emission. We don't need 100% unbiased unpredictability either, just a signal that cannot be predicted with much accuracy.
Also, the CC2531 looks like a QFN. Does it come in any hand-solderable packages?
http://moonbaseotago.com/onerng/theory.html
few (any?) chips that do 2.5GHz RF come in chips with traditional pins (too much inductance).
QFNs are completely hand solderable (with hot air, solder paste and a pair of tweezers)
As far as I'm aware, this means you could effect the numbers, by varying temperature.