Quote from: NLNico on June 06, 2016, 04:13:05 PM

satoshinonce would not be fair for investors and that site is technically not even provably fair for the player.

For player: if satoshinonce is also a miner, they could specify block-nonces (last 1 or 2 digits only) in their mining software which makes the incoming transactions/bets lose (or at least whichever is best for them.) So even if they have 2% mining power, players would most likely lose 2% more often. That's why I think for the player it's better to have TX+VOUT+SECRET like Luckyb.it (and SD before.) Might be tough to change it since.. well.. the site is called "Satoshi Nonce".

For investor: if satoshinonce is also a miner, they could adjust the mining software to only check nonces with 2 specific last digits and include some of those winning 98x transactions in it (and not even broadcast those transactions before finding the block!) Then if they find a correct block, they send it out including those winning transactions. It seems like a guaranteed way to win with no risk. So doesn't help investors much. Would be even worse for investors with TX id though obviously.

Also miners who like to attack/cheat satoshinonce can do this right now BTW. But I assume that adjusting the mining software to only use those specific nonces might take some work and I guess with the low max bet it's not worth it for them.

Quote from: RHavar on June 06, 2016, 09:45:11 PM

yeah, wtf? I never heard of this site, but they seem to do it in the worst possible way. As you note, it allows a miner to costlessly cheat the site. (miners can have a fixed nonce, and purely fiddle with the coinbase) and theoretically allow the site to cheat players (I doubt this would happen though, if they were sophisticated to know how to cheat players they would realize players can do the exact same attack against them).

Making bets on the last (couple?) digit of the block hash seems a lot smarter, as now miners have to discard blocks in order to cheat, which is rather expensive.

Thank you for the replies. Cheesy

I don't know much about mining either particularly in this case on what the nonce is etc.

https://en.bitcoin.it/wiki/Nonce

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The "nonce" in a bitcoin block is a 32-bit (4-byte) field whose value is set so that the hash of the block will contain a run of zeros. The rest of the fields may not be changed, as they have a defined meaning.

Any change to the block data (such as the nonce) will make the block hash completely different. Since it is believed infeasible to predict which combination of bits will result in the right hash, many different nonce values are tried, and the hash is recomputed for each value until a hash containing the required number of zero bits is found. As this iterative calculation requires time and resources, the presentation of the block with the correct nonce value constitutes proof of work.

So the nonce value is set by the miner. I was thinking it was automatically computed or something..

Quote

For investor: if satoshinonce is also a miner, they could adjust the mining software to only check nonces with 2 specific last digits and include some of those winning 98x transactions in it (and not even broadcast those transactions before finding the block!) Then if they find a correct block, they send it out including those winning transactions. It seems like a guaranteed way to win with no risk. So doesn't help investors much. Would be even worse for investors with TX id though obviously.

Yeah

Never thought of that.

So the block hash is the only reliable (or most reliable) string in a block that can be used for provably fair?