Danger! 51% attack possibility!

[btcsec]

I've just found out that BTCGuild with 14.5 GH/s now has more than 51% of network. This means double-spending attack possibility. Despite of BTCGuild's good reputation, the situation when the future of network depends on one person's decision contradicts the decentralization idea of Bitcoin.
We should do something, so I suggest BTCGuild users to switch to another pool, at least temporary, till BTCguild's power decrease to 40%.

[1714681358]

1714681358

[1714681358]

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[bitlancr]

http://blockchain.info/stats says the network hashrate is 34,523.40 GH/s. How does that make 14.5 GH/s more than 51%?

So with other words what you say makes no sense to me.

The numbers don't add up.

[VeeMiner]

it's close anyway. Some people should go to another pool to diversify. For example Slush

[BitcoinOxygen]

Yes, BTCGuild is bigger than any pool out there, But still not 51%.

Normally people mine on BTCGuild for the PPS option out there. There are many other PPS pools too. For Example BTCOxygen pays PPS.

[eleuthria]

BTC Guild's current speed is inflated as a result of the hard fork issue yesterday.  A significant number of Ozcoin users utilize BTC Guild as their backup server, so when Ozcoin went down, BTC Guild gained ~3-4 TH/s as a result.  I'm hopeful that during the day those users will return to Ozcoin.  I do not want to be in the position that Deepbit was in last year, but I'm hopeful the current situation is hopefully only temporary.

[crazyates]

The whole point of a 51% attack is that you can double spend, and then force the network to go along with it. IIRC, 51% of the hashrate gives you a 100% guarantee that at some point, you can double spend, and then mine 6 blocks in a row, forcing the confirmations. You don't need 51%, however, and it can be done with a lower hashrate. Ozcoin recently had 6 blocks in a row, and they're nowhere near 51%.

[malevolent]

You don't need 51%, however, and it can be done with a lower hashrate. Ozcoin recently had 6 blocks in a row, and they're nowhere near 51%.

This.

If you have a bit of luck you can double spend with 40% of total hashrate.
If you are luckier you could double spend with 20%.
If you are very lucky you could double spend with even less.

[yokosan]

1. Own a mining pool.
2. Contribute to update with hidden loop hole.
3. Create fork.
4. Become first pool to exploit hidden loophole in update.
5. Double spend + profit.

[|Dolphin|]

I am opening a pool soon. It should help the network.

[btcsec]

http://blockchain.info/stats says the network hashrate is 34,523.40 GH/s. How does that make 14.5 GH/s more than 51%?

This morning there was a moment when BTC Guild blocks / All blocks * 100 = 55%