4 ms·

I'm curious why they chose to use an avalanche diode which doesn't generate quantum-random numbers, unlike a reverse-biased transistor. As far as I'm aware, th

I'm curious why they chose to use an avalanche diode which doesn't generate quantum-random numbers, unlike a reverse-biased transistor. As far as I'm aware, this means you could effect the numbers, by varying temperature.

Taniwha 12y ago
actually it is a reverse biased transistor
- deutronium 12y ago
  Aha cool, is the schematic online?
  - Taniwha 12y ago
    not yet, the actual RNG circuit is pretty standard - we'll put up the eagle files, along with the software sources, before we open the kickstarter
    - joeschmoe097845 12y ago
      If it's faster, could you put up a .png of the schematic? Also, the CC2531 looks like a QFN. Does it come in any hand-solderable packages?
      - Taniwha 12y ago
        There's an almost current schematic on the "Theory of Operation" page: http://moonbaseotago.com/onerng/theory.html 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)
  - WaywardGeek 12y ago
    Every TRNG I've seen so far that uses "zener noise" is actually using the reverse breakdown voltage across the emitter-base junction of a cheap NPN transistor. This is a zener diode! The reason this form of zener is used is simply because the fab does not bother to put in any effort to reduce the avalanche noise. Noise like that makes zeners sold as zeners unpopular. 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.
raverbashing 12y ago
I doesn't matter. 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)
- deutronium 12y ago
  That's untrue, just because it's a semiconductor, doesn't mean it can't generate data effected by non-quantum properties such as temperature.
  - raverbashing 12y ago
    "it can't generate data effected by non-quantum properties such as temperature" And do you think quantum effects are not affected by temperature? REALLY?! Start here http://ecee.colorado.edu/~bart/book/distrib.htm http://ecee.colorado.edu/~bart/book/distrib.htm
DanBC 12y ago
https://news.ycombinator.com/item?id=7728216 https://news.ycombinator.com/item?id=7728216 > 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 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)

Taniwha 12y ago

actually it is a reverse biased transistor

deutronium 12y ago
Aha cool, is the schematic online?
- Taniwha 12y ago
  not yet, the actual RNG circuit is pretty standard - we'll put up the eagle files, along with the software sources, before we open the kickstarter
  - joeschmoe097845 12y ago
    If it's faster, could you put up a .png of the schematic? Also, the CC2531 looks like a QFN. Does it come in any hand-solderable packages?
    - Taniwha 12y ago
      There's an almost current schematic on the "Theory of Operation" page: http://moonbaseotago.com/onerng/theory.html 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)
- WaywardGeek 12y ago
  Every TRNG I've seen so far that uses "zener noise" is actually using the reverse breakdown voltage across the emitter-base junction of a cheap NPN transistor. This is a zener diode! The reason this form of zener is used is simply because the fab does not bother to put in any effort to reduce the avalanche noise. Noise like that makes zeners sold as zeners unpopular. 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.

raverbashing 12y ago

I doesn't matter. 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)

deutronium 12y ago
That's untrue, just because it's a semiconductor, doesn't mean it can't generate data effected by non-quantum properties such as temperature.
- raverbashing 12y ago
  "it can't generate data effected by non-quantum properties such as temperature" And do you think quantum effects are not affected by temperature? REALLY?! Start here http://ecee.colorado.edu/~bart/book/distrib.htm http://ecee.colorado.edu/~bart/book/distrib.htm

DanBC 12y ago

https://news.ycombinator.com/item?id=7728216 https://news.ycombinator.com/item?id=7728216 > 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 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)