On Thu, Oct 17, 2013 at 02:39:01PM -0700, Jon Callas wrote: > It is certainly true that radioactivity is a random effect, and is quantum > in nature. That does not mean that in order for a random sampling to be > quantum, it must be based on radioactivity; there are other quantum sources > of randomness. Noisy diodes, resister noise, CCD noise, etc. are all quantum. > If you want to get picky, *all* physical effects are quantum, even ones that > aren't usefully random. There is nothing magic about one physical source or > other that makes it more suited for crypto. Thinking that a hardware source > should be radioactive is affirming the consequence, as well.
Radioactivity is almost uniquely insensitive to tampering through environmental influences, though, owing to the large energy scale of nuclear processes [1]. Unfortunately, it does not automatically follow that the circuit used to detect it is also similarly robust, and NSA would probably be able to easily develop the capability to eavesdrop on Geiger-counter based RNGs if they become widespread. A high DC voltage, and abrupt current pulses - this is sounding rather similar to a spark-gap transmitter. [1] A handful of exceptions exist involving low-energy beta decays, such as Dy-163 and Re-187. -- Andrea Shepard <[email protected]> PGP fingerprint (ECC): 2D7F 0064 F6B6 7321 0844 A96D E928 4A60 4B20 2EF3 PGP fingerprint (RSA): 7895 9F53 C6D1 2AFD 6344 AF6D 35F3 6FFA CBEC CA80
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