3 ms·
> Years later it dawned on me that it would also be a good source of random data if it at a suitable frequency was fed through an ADC. To be pedantic, I think
by pipo234 3y ago
> Years later it dawned on me that it would also be a good source of random data if it at a suitable frequency was fed through an ADC.
To be pedantic, I think you mean good source of entropy, rather than random data. The raw ADC data is likely to have statistic (Gaussian) bias, which would mean trouble if randomness in the crypto sense were the objective. Ie. you would need to whiten the bitstream (using some kind of hash) to make it useful in a (P)RNG.
But nevertheless, a great idea to start with: cheap and relatively reliable.
- daneel_w 3y ago> "To be pedantic, I think you mean good source of entropy, rather than random data. The raw ADC data is likely to have statistic (Gaussian) bias ..." It might have. There are also various ways of affecting the spectrum of the noise generated by the transistor using electromagnetic and thermal influence. But can you can positively discern that output as absolutely biased or affected, and crucially would you be able to take actual advantage of it? I'm not really certain, but for this type of solution I'd still err on the side of it not being a feasible attack.
- dahart 3y agoIt’s okay for people to use the word “random” without meaning secure cryptographic randomness, even in a technical setting. To be pedantic myself, the word “random” has many legitimate meanings, so we don’t need to impose the most strict version of our favorite term of art on people any time an overloaded word is used, right? It’s fine to ask or point out or discuss the nuance, but saying “I think you mean X” is likely to be an incorrect assumption, no?