One time, my wife and siblings had to choose from a number of heirlooms that had be left to them but not assigned. They are living around the planet, and the discussion came up about how to decide the order in which they'd select the items.
I came up with this: Each of them select a different stock market index. On the same calendar trading day, they choose two digits past the decimal. When the market's close, compare the two digits of the closing price of their chosen index to the two digits they selected and then choose heirlooms in the order of closeness.
It worked quite well. They were on board because they could make two selections in determining their order: Market and digits. Two of them could choose the same two digits if they wanted and still have different scores. No complaints.
Another possibility: hold a private auction among the siblings and give the proceeds to the favorite charity of the person who left the heirlooms. It's fair [1], honors their memory, and makes the world a better place all at once. Three-way win.
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[1] You can compensate for unequal economic situations by limiting the total amount that any one person can bid to a value that they can all afford.
This is one of the craziest, most convoluted approaches to randomness I've ever heard of. I love it. Personally, I would've just had a third-party roll a die to establish the order. If there's a tie, roll again. More than 6 siblings? Two dice. Fun for the whole family! (and would take just a few minutes)
Yes, thanks for prompting my memory. We needed an approach that put all five of the siblings on the same footing. Even a third party chosen by one of the five may not be trusted since the others may not know the party.
It was goofy, but satisfied them all without dissent. And it worked!
The least significant bits of a bitcoin PoW hash behave pretty randomly.
You could either bet on a fixed future block height, or on the first block past a given future timestamp...
That's actually very easy to control. Just pay a high transaction fee. The nonce comes from a PRNG that doesn't have to pass many randomness checks. Your proposal really is no more random than a counter based SHA256 PRNG except with an awfully high sample latency.
I came up with this: Each of them select a different stock market index. On the same calendar trading day, they choose two digits past the decimal. When the market's close, compare the two digits of the closing price of their chosen index to the two digits they selected and then choose heirlooms in the order of closeness.
It worked quite well. They were on board because they could make two selections in determining their order: Market and digits. Two of them could choose the same two digits if they wanted and still have different scores. No complaints.
Not random, but seemed fair to all.