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It's interesting that a blockchain of random values with timestamps is created by this, but I fail to see how this helps in most of the applications listed in t

It's interesting that a blockchain of random values with timestamps is created by this, but I fail to see how this helps in most of the applications listed in their applications poster.[1] (warning - PDF) There needs to be some other time-stamped blockchain that allows the submission of hashes of the results of applying the random data. Otherwise you could retroactively tweak your results, in a manner like phi-hacking. [1] https://csrc.nist.gov/CSRC/media/Presentations/usages-of-public-randomness/images-media/20191106-NIST-ITL-Science-Day-poster-Beacon--ts-20191118.pdf https://csrc.nist.gov/CSRC/media/Presentations/usages-of-pub...

sparsely 2y ago
I think you are meant to commit to using the value of the beacon at a future point in time, e.g. when you're preregistering your trial methodology.
- magicalhippo 2y ago
  Couldn't you also just use the (salted) beacon value itself as the key for a HMAC of the ordered list of the people you assigned?
  - deleted 2y ago
    [deleted]
crote 2y ago
Let's say you are organizing a sports event. In a knockout tournament it is really advantageous if you could only face weaker teams, until the final game where you face a team which had to fight all the other strong teams instead. Two months prior to the event you number each initial spot in the bracket, and you assign a number to each team - sort them alphabetically or something, it doesn't really matter. You tell everyone that assignment will be done by shuffling using a well-known PRNG, and you'll take the beacon value one month from the event as seed. The T minus 1 month point is reached, you download the beacon value, feed it into the PRNG, and shuffle the teams to get the final bracket. The algorithm and all inputs except the randomness was fixed in advance, so you cannot manipulate that. You have committed to the seed without knowing it, so you could not have possibly manipulated the seed either. Everyone can verify this, so everyone will agree that the drawing was done fairly.

sparsely 2y ago

I think you are meant to commit to using the value of the beacon at a future point in time, e.g. when you're preregistering your trial methodology.

magicalhippo 2y ago
Couldn't you also just use the (salted) beacon value itself as the key for a HMAC of the ordered list of the people you assigned?
- deleted 2y ago
  [deleted]

crote 2y ago

Let's say you are organizing a sports event. In a knockout tournament it is really advantageous if you could only face weaker teams, until the final game where you face a team which had to fight all the other strong teams instead. Two months prior to the event you number each initial spot in the bracket, and you assign a number to each team - sort them alphabetically or something, it doesn't really matter. You tell everyone that assignment will be done by shuffling using a well-known PRNG, and you'll take the beacon value one month from the event as seed. The T minus 1 month point is reached, you download the beacon value, feed it into the PRNG, and shuffle the teams to get the final bracket. The algorithm and all inputs except the randomness was fixed in advance, so you cannot manipulate that. You have committed to the seed without knowing it, so you could not have possibly manipulated the seed either. Everyone can verify this, so everyone will agree that the drawing was done fairly.