Author

Topic: Provably fair unknown event time for Bitcoin gambling (Read 849 times)

legendary
Activity: 1512
Merit: 1032
A method I have just devised for a daily jackpot:

First block with UTC timestamp after specified time determines winner,
Users can supply or transaction ID generates their "random" number,
Lowest result of SHA256(block hash + user nonce) wins.

This still allows the house to cheat though, as they can enter their own drawing for free.
legendary
Activity: 1512
Merit: 1032
You could draw a winner as soon as the newest Bitcoin block hash contains a certain sequence.

That would be my thinking; however the blockchain doesn't provide a statistically constant rate of blocks, because mining isn't constant. If the goal is to generate on average one "event" per day or per week, it will still take manual intervention if the Bitcoin hashrate is increasing or decreasing, or above or below the difficulty; the actual hashrate cannot be determined to make it fair.

In addition, a criteria that may happen on average once per week (such as block hash mod 1008 = 0) has a not-insignificant chance of taking over a month, which may make players restless.

A better solution would be a satoshi-dice style provable, where the random choosing method for transactions sent into the jackpot pool is transaction hash plus site's secret which is pre-published as a hash. For example, if one in 16 bets may win the whole jackpot, etc... If I need to explain more, you shouldn't be running a gambling site.
legendary
Activity: 2212
Merit: 1199
You could draw a winner as soon as the newest Bitcoin block hash contains a certain sequence.

oh yes that would be nice Wink


good luck with your project!


regards!
full member
Activity: 164
Merit: 100
You could draw a winner as soon as the newest Bitcoin block hash contains a certain sequence.
member
Activity: 82
Merit: 10
or is there a word provably which I am not aware of ?

"Provably" is the adverb form of provable, meaning something which can be proven.

full member
Activity: 154
Merit: 100
You posted exactly same thread on bitcoin.stackexchange.com I am confused that you used word Provably in the title on both sites are you intentionally writing provably or its copy paste job ? or is there a word provably which I am not aware of ?
sr. member
Activity: 364
Merit: 264
Random.org offers JSON data that can be verified: https://api.random.org/verify

In beta until June 2014, when it'll no longer be free (apparently)
newbie
Activity: 14
Merit: 0

I have a bitcoin lottery that is still in the prototype stage (bitsplit.it).

I believe that the game will be much more appealing, for certain reasons, if players (and the house) both don't know when the next winner will be chosen.

However, I am having a hard time with coming up with a (feasible) way to prove that the house doesn't know when the pot will split.

Any ideas are greatly appreciated.



live feed of the draw is the best i've come up with...:-)
newbie
Activity: 11
Merit: 0

I have a bitcoin lottery that is still in the prototype stage (bitsplit.it).

I believe that the game will be much more appealing, for certain reasons, if players (and the house) both don't know when the next winner will be chosen.

However, I am having a hard time with coming up with a (feasible) way to prove that the house doesn't know when the pot will split.

Any ideas are greatly appreciated.
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