Topic: Mining Cluster Question regarding cheating. (Read 1067 times)

I think we need to back up a bit.  A solved block means you took some data and mixed it with your own made up data and the resulting hash was a lower value than xxxxxxxxxxxxxxxxxxxxxxxxxxxxx <-- basically the difficulty level.  Hashing results in an unpredictable value that isn't reversible to find the source data.  So if you has 12345 and it ends up as 96834, you don't know that 12345 was the original data.  You also didn't know that 96834 was going to be the result.

So to solve a block on the main bitcoin network, you have to keep trying values until you get one that results in a value below the difficulty target.  A portion of the data used to be hashed is static data that you can't change because it contains data about the block and transactions too or whatever.  The other part is a random number that your miner tries.  I think it's in sequence too so you don't try the same one twice.  A third part is which address you are so they can give you 25BTC for solving it and that becomes part of the block.

In a pool, they just want you to prove that you're actually doing real work at the rate you say you are.  So they'll take the network difficulty and low is by like 10,000 and every time your hash is below that limit, it counts as a share after they verify it was calculated correctly.  So if you solve the block, is has the wallet address embedded in it so it's theirs when you solve it and you can't walk off with the 25BTC

A share is a lower difficulty hash.  It has no value in the Bitcoin network.  Pools use them as a method of record keeping.  For example if you submit 10% of the shares then you get 10% of the reward.   Traditionally shares were difficulty 1 so if difficulty for a block is 25,000,000 then a share is 25 million times easier to find and on average the pool collectively will find 25,000,000 shares for every block.  Shares can be any difficulty (remember they are worthless and simply are an arbitrary mechansim of accounting) and some pools now use higher difficulty or even variable difficulty.

Good find.. but still i am confused for
if you find a share is a block or what?

just searched for the thread: https://bitcointalksearch.org/topic/m.1043633

Ah genius! Thanks.

Scenario 1 happens always when you dont find the block and someone else (asuming none PPS system) finds the block (ur golden ticket)
Scenario 2 isnt possible, the data ur hashing is connected with a "seed", it contains the address of the pools owner in case the resulting hash solves a block. therefore if u change this adress the whole hash is invalid. altough u can withhold it so pool dosnt find the block, but u only hurt urself. u can destroy PPS pools with that (i discussed this already with ckolivas, just search for it) but u have to pay for it and have enough hashing power.

I'm sure this scenario has been thought of but can someone tell me why the following can't happen :

Scenario 1
1) A malicious user joins a mining pool
2) The mining pool dishes out some hashes to try -  he doesn't get the "golden ticket" this time, but does get a share of the effort (as per normal)

Scenario 2
1) Same malicious user joins mining pool
2) Malicious user finds the winning hash but then does not report it back to the pool, but claims it for himself.
3) Mining pool loses out on the mining reward.

Thanks.