<p>There is no magic barrier above which you will make a profit, it's a tradeoff. The larger your hashrate the higher your chances of successfully completing the finney attack. The odds at SatoshiDice are a bit at your disadvantage, but in a system where you'd get back what you wagered in expectation you'd always make a profit.</p>

CC BY-SA 3.0
2013-11-25T12:36:40.953Z
Sorry, I meant over time, I should have been more clear. I know that for each individual one, it's random, like flipping a coin. However if you attempt this repeatedly, what hashrate that you need to make a profit?
lurf jurv
CC BY-SA 3.0
2013-11-25T09:41:32.647Z
2013-11-25T09:41:32.647Z
cdecker
<p>Say I have an address with 1000 different 0.01BTC outputs. I send all of the outputs (in separate transactions) to the 48% SatoshiDICE address. At the same time, I craft a transaction for each of the outputs that sends the money back to myself. Once I find out which of the bets succeeded, I start mining. I include the SatoshiDICE bets where I won, and I cancel the ones where I lost (using the conflicting transaction I generated earlier). So basically if I mine the next block, I cancel all the bets where I lost, and only keep the ones where I won. My question is, what percent of the network hashrate do I need to make this profitable?</p>

CC BY-SA 3.0
2013-11-25T00:48:39.160Z
I seem to recall hearing that mining clients may refuse to build on blocks that include a lot of transactions they haven't seen.  If that's true, then you risk having your block rejected and losing your reward.
Nate Eldredge
CC BY-SA 3.0
2013-11-25T10:32:09.783Z
The question is closely related, but this one focuses more on the hash-rate required.
Murch
<security><hashpower><satoshidice><finney-attack>
Hashrate required for Finney attack on SatoshiDICE
lurf jurv
# Hashrate required for Finney attack on SatoshiDICE

(Asked by: username_0 on 2013-11-24)

Say I have an address with 1000 different 0.01BTC outputs. I send all of the outputs (in separate transactions) to the 48% SatoshiDICE address. At the same time, I craft a transaction for each of the outputs that sends the money back to myself. Once I find out which of the bets succeeded, I start mining. I include the SatoshiDICE bets where I won, and I cancel the ones where I lost (using the conflicting transaction I generated earlier). So basically if I mine the next block, I cancel all the bets where I lost, and only keep the ones where I won. My question is, what percent of the network hashrate do I need to make this profitable?

**Tags:** security, hashpower, satoshidice, finney-attack

> **Comments:**
> **username_1**: I seem to recall hearing that mining clients may refuse to build on blocks that include a lot of transactions they haven't seen.  If that's true, then you risk having your block rejected and losing your reward.  
> **username_2**: The question is closely related, but this one focuses more on the hash-rate required.  

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## 1 answers

### Answer by username_3 on 2013-11-25. Score: 0

There is no magic barrier above which you will make a profit, it's a tradeoff. The larger your hashrate the higher your chances of successfully completing the finney attack. The odds at SatoshiDice are a bit at your disadvantage, but in a system where you'd get back what you wagered in expectation you'd always make a profit.

> **Comments:**
> **username_0**: Sorry, I meant over time, I should have been more clear. I know that for each individual one, it's random, like flipping a coin. However if you attempt this repeatedly, what hashrate that you need to make a profit?  

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