[cgjaro]

This DC cost $100 million. Not exactly pocket change. http://www.coindesk.com/bitfury-details-100-million-georgia-...

Plus, with BitFury online, the cost of a 51% attack just raised to $200 million.

The only reason it is (currently, for a short time) hypothetically possible to 51%-attack the network with a budget in the low hundreds of million of dollars is because most of the miners are not using such efficient 16 nm chips. As the market migrate to these last generation chips, expect the cost to increase to $1+ billion in the next year.

[Sealy]

People seem to forget that it is NOT in BitFury's best interest to perform a 51% attack because, bitcoin's value will plummet if they do that.

[mootothemax]

>People seem to forget that it is NOT in BitFury's best interest to perform a 51% attack because, bitcoin's value will plummet if they do that.

If BitFury can turn $200 million into $400 million now rather than over a couple of years, why on earth would they care about the side-effect of killing off bitcoin?

For the avoidance of doubt, I think that BitFury's best interest is BitFury; as long as they make a decent chunk of money, the end result for bitcoin is - and should be - immaterial to them.

[fla]

Yes but in practice you can't convert that much BTC into USD that quickly.

[mootothemax]

>Yes but in practice you can't convert that much BTC into USD that quickly.

Would they even need to convert BTC into USD? Even ignoring the obvious opportunities for shorting an entire economy?

I mean, I'm kinda curious to know what effects they could cause by e.g. choosing to mine zero-block transactions for a few days.

[bryanbuckley]

I thought miners already try to mine zero block transactions first, then add in fee transactions? apparently you can chew through the nonce really fast..

[adam_mckenna]

Not exactly. Some Chinese mining firms maintain a stratum connection to pools in the US so they can get just the new block header when a new block is found on the network. They then mine on that header until the full block is downloaded and validated by their local bitcoind (which can take 20 seconds, to several minutes in the worst case) This has been referred to as "SPV Mining".

If they find the next block during the time they are mining only against the block header, that block will contain no transactions. This doesn't happen very often, and there are some other issues that can arise from the practice (a multi-block fork happened once), but miners believe that it increases their profitability so (afaik) they continue to do it. More info here: http://bitcoin.stackexchange.com/questions/38437/what-is-spv...

[cma]

But if that was a predictable consequence, they can't turn $200million into $400million now, because other would anticipate the future state of things and the price would plummet before a couple years. Not that I think that is at all what is going to happen.

[mootothemax]

>because other would anticipate the future state of things and the price would plummet before a couple years.

Why would the price plummeting matter to them if they've already made their money?

[x3c]

The only way they make money (cash out) is if trust remains in the bitcoin platform. By doing 51%, they tank the platform itself. No liquidity. Provable and transparent majority attack is MAD in the strictest sense.

[mootothemax]

>The only way they make money (cash out) is if trust remains in the bitcoin platform.

Not if their cash isn't - somewhat ironically - tied up in BTC.

Really, I'm sure between the two of us, we could imagine a thousand and one viable ways of making a tonne of cash very, very quickly that wouldn't involve transacting in BTC at any point!

[Retric]

As the mining rewards keep lowering it's getting to the point here someone is going to do this for the lulz. As to cost you can sell all your coins before doing a 51% attack. Short the market and at some point it might even be proffitable to do so.

[gcr]

Yeah, but how many bitcoins is USD$ 100 million worth?

[ragnar123]

229922 BTC according to Google's exchange rates.

See: https://www.google.com/search?q=100M+usd+in+bitcoin

[sanswork]

Or you could just buy bit fury

[maaku]

Or be the sovereign state whose jurisdiction that data center is in.

[cgjaro]

You couldn't buy BitFury for less than 200 or 300 million dollar. After all they expect this $100 million data center to be profitable so I am sure they value their company at least 2x or 3x this.

[creshal]

It's not pocket change… except for government organizations.

[davidgerard]

It is profoundly unlikely a state-level actor would bother.

You can cripple Bitcoin transaction clearing with a thousand dollars to DDOS the network with spam. If only state-level actors had a thousand bucks lying around ...