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Bitcoin => Bitcoin Discussion => Topic started by: jhansen858 on May 19, 2013, 07:05:21 AM



Title: 51% attack possible ?
Post by: jhansen858 on May 19, 2013, 07:05:21 AM
http://bitnodes.io/

It appears that china has more nodes then any other country.  51% attack possible if they get more than half of the nodes?


Title: Re: 51% attack possible ?
Post by: solex on May 19, 2013, 07:14:59 AM
http://bitnodes.io/

It appears that china has more nodes then any other country.  51% attack possible if they get more than half of the nodes?

It's not nodes which matter. Its hashing power (averaged out over a few days). However, China has been leading the way with ASIC development, which gives them a good chunk of the hashing power too. Hopefully this is temporary as BFL and others finally get into the market.

Great site for providing a measure of decentralization, which is sorely needed for the block size debate.


Title: Re: 51% attack possible ?
Post by: salvani on May 19, 2013, 10:16:39 AM
This link (http://blockorigin.pfoe.be/chart.php) will perfectly show you the chances of 51% attack.


Title: Re: 51% attack possible ?
Post by: cypherdoc on May 19, 2013, 02:00:09 PM
http://bitnodes.io/

It appears that china has more nodes then any other country.  51% attack possible if they get more than half of the nodes?

Whoa, is that right?

The node globe on blockchain. Info showed almost no nodes at all less than a year ago!


Title: Re: 51% attack possible ?
Post by: oakpacific on May 19, 2013, 04:05:10 PM
http://bitnodes.io/

It appears that china has more nodes then any other country.  51% attack possible if they get more than half of the nodes?

It's not nodes which matter. Its hashing power (averaged out over a few days). However, China has been leading the way with ASIC development, which gives them a good chunk of the hashing power too. Hopefully this is temporary as BFL and others finally get into the market.

Great site for providing a measure of decentralization, which is sorely needed for the block size debate.

Yup, Chinese should only occupy as big a percentage as their IMF voting power, so that everyone will feel safe.

Otoh, I would like to remind everyone that a more imminent danger to Bitcoin network is the total disparity of hashing power between genders and people with different orientations, males and heterosexuals control way more hashing power than females and homosexuals, who could be easily 51% attacked, and maybe even 90% attacked by the stronger majorities! Let us start some affirmative actions and donate our hashing power to the minorities!


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 19, 2013, 11:11:00 PM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.


Title: Re: 51% attack possible ?
Post by: solex on May 19, 2013, 11:29:37 PM
http://bitnodes.io/

It appears that china has more nodes then any other country.  51% attack possible if they get more than half of the nodes?

Whoa, is that right?

The node globe on blockchain. Info showed almost no nodes at all less than a year ago!

China is top here for May 2013 so far:

http://sourceforge.net/projects/bitcoin/files/stats/map?dates=2013-05-01%20to%202013-05-19


Title: Re: 51% attack possible ?
Post by: Ozymandias on May 19, 2013, 11:42:56 PM
http://bitnodes.io/

It appears that china has more nodes then any other country.  51% attack possible if they get more than half of the nodes?

It's not nodes which matter. Its hashing power (averaged out over a few days). However, China has been leading the way with ASIC development, which gives them a good chunk of the hashing power too. Hopefully this is temporary as BFL and others finally get into the market.

Great site for providing a measure of decentralization, which is sorely needed for the block size debate.

Yup, Chinese should only occupy as big a percentage as their IMF voting power, so that everyone will feel safe.

Otoh, I would like to remind everyone that a more imminent danger to Bitcoin network is the total disparity of hashing power between genders and people with different orientations, males and heterosexuals control way more hashing power than females and homosexuals, who could be easily 51% attacked, and maybe even 90% attacked by the stronger majorities! Let us start some affirmative actions and donate our hashing power to the minorities!

That's so speciest! What about the poor hashless dogs, cats, cows, etc.?!


Title: Re: 51% attack possible ?
Post by: oakpacific on May 19, 2013, 11:54:23 PM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 19, 2013, 11:56:58 PM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?


Title: Re: 51% attack possible ?
Post by: oakpacific on May 20, 2013, 12:02:36 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 20, 2013, 12:11:44 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.

That's far from the destruction of Bitcoin. They can do what they want in China, but not the rest of the world.


Title: Re: 51% attack possible ?
Post by: oakpacific on May 20, 2013, 12:15:55 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.

That's far from the destruction of Bitcoin. They can do what they want in China, but not the rest of the world.

No, per the status quo it would have the same effect: right now there is no viable ASIC producer out of China(BFL honestly is not there yet), if there will be at least one in the future, whatever China will do doesn't matter, people can just switch to the out of China producers. If there will not, then the "$5 wretch" attack still works.


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 20, 2013, 12:23:21 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.

That's far from the destruction of Bitcoin. They can do what they want in China, but not the rest of the world.

No, per the status quo it would have the same effect: right now there is no viable ASIC producer out of China(BFL honestly is not there yet), if there will be at least one in the future, whatever China will do doesn't matter, people can just switch to the out of China producers. If there will not, then the "$5 wretch" attack still works.

Even if there were no more ASICs produced, the current nodes would maintain the network.


Title: Re: 51% attack possible ?
Post by: oakpacific on May 20, 2013, 12:28:38 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.

That's far from the destruction of Bitcoin. They can do what they want in China, but not the rest of the world.

No, per the status quo it would have the same effect: right now there is no viable ASIC producer out of China(BFL honestly is not there yet), if there will be at least one in the future, whatever China will do doesn't matter, people can just switch to the out of China producers. If there will not, then the "$5 wretch" attack still works.

Even if there were no more ASICs produced, the current nodes would maintain the network.

You didn't get me: the "$5 wretch" attack applies because had the CCP wanted to 51% attack the network, the easiest way to do it would be to arrest the ASICMiner/Avalon people for things like tax evasion, and confiscate all their blueprints, drawings, VHDL programs, manufacturing equipments so that they can easily replicate their own ASICs. Why buying/developing your own when you can get them for much cheaper?

Besides, given how competent friedcat has been demonstrated to be, it's most possible that he has already correctly assessed the risk.


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 20, 2013, 12:48:14 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.

That's far from the destruction of Bitcoin. They can do what they want in China, but not the rest of the world.

No, per the status quo it would have the same effect: right now there is no viable ASIC producer out of China(BFL honestly is not there yet), if there will be at least one in the future, whatever China will do doesn't matter, people can just switch to the out of China producers. If there will not, then the "$5 wretch" attack still works.

Even if there were no more ASICs produced, the current nodes would maintain the network.

You didn't get me: the "$5 wretch" attack applies because had the CCP wanted to 51% attack the network, the easiest way to do it would be to arrest the ASICMiner/Avalon people for things like tax evasion, and confiscate all their blueprints, drawings, VHDL programs, manufacturing equipments so that they can easily replicate their own ASICs. Why buying/developing your own when you can get them for much cheaper?

Besides, given how competent friedcat has been demonstrated to be, it's most possible that he has already correctly assessed the risk.

OK. That's another whey they could pull off a 51% attack.


Title: Re: 51% attack possible ?
Post by: oakpacific on May 20, 2013, 12:53:51 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.

That's far from the destruction of Bitcoin. They can do what they want in China, but not the rest of the world.

No, per the status quo it would have the same effect: right now there is no viable ASIC producer out of China(BFL honestly is not there yet), if there will be at least one in the future, whatever China will do doesn't matter, people can just switch to the out of China producers. If there will not, then the "$5 wretch" attack still works.

Even if there were no more ASICs produced, the current nodes would maintain the network.

You didn't get me: the "$5 wretch" attack applies because had the CCP wanted to 51% attack the network, the easiest way to do it would be to arrest the ASICMiner/Avalon people for things like tax evasion, and confiscate all their blueprints, drawings, VHDL programs, manufacturing equipments so that they can easily replicate their own ASICs. Why buying/developing your own when you can get them for much cheaper?

Besides, given how competent friedcat has been demonstrated to be, it's most possible that he has already correctly assessed the risk.

OK. That's another whey they could pull off a 51% attack.

It would be so visible that it makes no sense to pull it off at all.


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 20, 2013, 01:12:05 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.

That's far from the destruction of Bitcoin. They can do what they want in China, but not the rest of the world.

No, per the status quo it would have the same effect: right now there is no viable ASIC producer out of China(BFL honestly is not there yet), if there will be at least one in the future, whatever China will do doesn't matter, people can just switch to the out of China producers. If there will not, then the "$5 wretch" attack still works.

Even if there were no more ASICs produced, the current nodes would maintain the network.

You didn't get me: the "$5 wretch" attack applies because had the CCP wanted to 51% attack the network, the easiest way to do it would be to arrest the ASICMiner/Avalon people for things like tax evasion, and confiscate all their blueprints, drawings, VHDL programs, manufacturing equipments so that they can easily replicate their own ASICs. Why buying/developing your own when you can get them for much cheaper?

Besides, given how competent friedcat has been demonstrated to be, it's most possible that he has already correctly assessed the risk.

OK. That's another whey they could pull off a 51% attack.

It would be so visible that it makes no sense to pull it off at all.

Why would they care about visibility? Bitcoin's not a national currency.


Title: Re: 51% attack possible ?
Post by: oakpacific on May 20, 2013, 01:18:03 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.

That's far from the destruction of Bitcoin. They can do what they want in China, but not the rest of the world.

No, per the status quo it would have the same effect: right now there is no viable ASIC producer out of China(BFL honestly is not there yet), if there will be at least one in the future, whatever China will do doesn't matter, people can just switch to the out of China producers. If there will not, then the "$5 wretch" attack still works.

Even if there were no more ASICs produced, the current nodes would maintain the network.

You didn't get me: the "$5 wretch" attack applies because had the CCP wanted to 51% attack the network, the easiest way to do it would be to arrest the ASICMiner/Avalon people for things like tax evasion, and confiscate all their blueprints, drawings, VHDL programs, manufacturing equipments so that they can easily replicate their own ASICs. Why buying/developing your own when you can get them for much cheaper?

Besides, given how competent friedcat has been demonstrated to be, it's most possible that he has already correctly assessed the risk.

OK. That's another whey they could pull off a 51% attack.

It would be so visible that it makes no sense to pull it off at all.

Why would they care about visibility? Bitcoin's not a national currency.

If they don't care about publicity, I believe they would do it my way, as long as everyone is safe and sound, no need to worry. If they do care, then they would not pull off a 51%. Of course there are all under the condition that China is not interested in Bitcoin itself.

Also, it needs to be pointed out that Bitcoin is great because it doesn't care about your political ideology, cultural background, social status and whatsoever, everyone can benefit from it other than possibly the staunchest banking system supporters, it's best not to make too big a fuss out of this if we don't have hard evidence.


Title: Re: 51% attack possible ?
Post by: SamS on May 20, 2013, 01:26:21 AM

This is the kind of thread that convinces me that the "market" hasn't really priced in enough Bitcoin "risk" at all...


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 20, 2013, 01:36:29 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.

That's far from the destruction of Bitcoin. They can do what they want in China, but not the rest of the world.

No, per the status quo it would have the same effect: right now there is no viable ASIC producer out of China(BFL honestly is not there yet), if there will be at least one in the future, whatever China will do doesn't matter, people can just switch to the out of China producers. If there will not, then the "$5 wretch" attack still works.

Even if there were no more ASICs produced, the current nodes would maintain the network.

You didn't get me: the "$5 wretch" attack applies because had the CCP wanted to 51% attack the network, the easiest way to do it would be to arrest the ASICMiner/Avalon people for things like tax evasion, and confiscate all their blueprints, drawings, VHDL programs, manufacturing equipments so that they can easily replicate their own ASICs. Why buying/developing your own when you can get them for much cheaper?

Besides, given how competent friedcat has been demonstrated to be, it's most possible that he has already correctly assessed the risk.

OK. That's another whey they could pull off a 51% attack.

It would be so visible that it makes no sense to pull it off at all.

Why would they care about visibility? Bitcoin's not a national currency.

If they don't care about publicity, I believe they would do it my way, as long as everyone is safe and sound, no need to worry. If they do care, then they would not pull off a 51%. Of course there are all under the condition that China is not interested in Bitcoin itself.

Also, it needs to be pointed out that Bitcoin is great because it doesn't care about your political ideology, cultural background, social status and whatsoever, everyone can benefit from it other than possibly the staunchest banking system supporters, it's best not to make too big a fuss out of this if we don't have hard evidence.


How can there be hard evidence, if it hasn't happened yet? And you've just given an example of how it can happen.

Of course, Bitcoin is revolutionary. But ignoring an issue doesn't make it go away.


Title: Re: 51% attack possible ?
Post by: BTCnewbie on May 20, 2013, 01:36:41 AM
I thought this thread was referring to another 9th of November. I had my hopes up. Seriously disappointed and I'm not even "ayrab" or "eye raqui"


Title: Re: 51% attack possible ?
Post by: oakpacific on May 20, 2013, 01:46:08 AM
A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed.

I should apply XKCD's famous "$5 wretch" argument here: if an authoritarian government wants to screw you, there are much easier ways to do it than a 51% attack, otherwise if they want to play, they would be very careful to not tip the balance.

Like what?

Shutdown ASICMiner and Avalon, arrest everyone and scare the daylight out of all the remaining Chinese miners.

That's far from the destruction of Bitcoin. They can do what they want in China, but not the rest of the world.

No, per the status quo it would have the same effect: right now there is no viable ASIC producer out of China(BFL honestly is not there yet), if there will be at least one in the future, whatever China will do doesn't matter, people can just switch to the out of China producers. If there will not, then the "$5 wretch" attack still works.

Even if there were no more ASICs produced, the current nodes would maintain the network.

You didn't get me: the "$5 wretch" attack applies because had the CCP wanted to 51% attack the network, the easiest way to do it would be to arrest the ASICMiner/Avalon people for things like tax evasion, and confiscate all their blueprints, drawings, VHDL programs, manufacturing equipments so that they can easily replicate their own ASICs. Why buying/developing your own when you can get them for much cheaper?

Besides, given how competent friedcat has been demonstrated to be, it's most possible that he has already correctly assessed the risk.

OK. That's another whey they could pull off a 51% attack.

It would be so visible that it makes no sense to pull it off at all.

Why would they care about visibility? Bitcoin's not a national currency.

If they don't care about publicity, I believe they would do it my way, as long as everyone is safe and sound, no need to worry. If they do care, then they would not pull off a 51%. Of course there are all under the condition that China is not interested in Bitcoin itself.

Also, it needs to be pointed out that Bitcoin is great because it doesn't care about your political ideology, cultural background, social status and whatsoever, everyone can benefit from it other than possibly the staunchest banking system supporters, it's best not to make too big a fuss out of this if we don't have hard evidence.


How can there be hard evidence, if it hasn't happened yet? And you've just given an example of how it can happen.

Of course, Bitcoin is revolutionary. But ignoring an issue doesn't make it go away.

Example of a hard evidence: friedcat is arrested, in that case everyone better prepare for a Chinese takeover.

Otherwise there is no reason to be vigilant just because the world's most populous/biggest manufacturing nation happen to have the biggest number of mining nodes. Or it wll be something like:"people under a different system should not be allowed to touch Bitcoin mining."


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 20, 2013, 01:58:50 AM
Or they could just muster the resources and do it anyway, with no warning.


Title: Re: 51% attack possible ?
Post by: oakpacific on May 20, 2013, 02:05:04 AM
Or they could just muster the resources and do it anyway, with no warning.

No unusual mining power growth can escape people's attention, you get the most paranoid bunch of guys in the world here, why bother with additional resources?

And it's not even relevant, any prevention against 51% attack has to be implemented such that it's effective against all possible 51% attacks(which you have to do  anyway if you can), to just target a particular group of people is ridiculous.


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 20, 2013, 02:15:05 AM
Or they could just muster the resources and do it anyway, with no warning.

No unusual mining power growth can escape people's attention, you get the most paranoid bunch of guys in the world here, why bother with additional resources?

And it's not even relevant, any prevention against 51% attack has to be implemented such that it's effective against all possible 51% attacks(which you have to do  anyway if you can), to just target a particular group of people is ridiculous.

They would do it as closely together as possible. They're unlikely to connect one machine at a time to the network.

It's an example of a nation. But yes, it could be any nation with enough resources.


Title: Re: 51% attack possible ?
Post by: oakpacific on May 20, 2013, 02:25:46 AM
Or they could just muster the resources and do it anyway, with no warning.

No unusual mining power growth can escape people's attention, you get the most paranoid bunch of guys in the world here, why bother with additional resources?

And it's not even relevant, any prevention against 51% attack has to be implemented such that it's effective against all possible 51% attacks(which you have to do  anyway if you can), to just target a particular group of people is ridiculous.

They would do it as closely together as possible. They're unlikely to connect one machine at a time to the network.

It's an example of a nation. But yes, it could be any nation with enough resources.

Exactly, so it's not related to how many nodes are, or even how much hashpower is in China, right?

Not to say a 51% attack can only be pulled off by a single node with 51% of the hashing power, not a lot of nodes combined together.

So what OP said is not relevant.

I spoke of "other ways", the fact is that even China tries to play fairly, with its cheap mid-level skilled labor and supply chain and cheap electricity, no other nation in the world can match it in mining capability.


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 20, 2013, 02:32:31 AM
Or they could just muster the resources and do it anyway, with no warning.

No unusual mining power growth can escape people's attention, you get the most paranoid bunch of guys in the world here, why bother with additional resources?

And it's not even relevant, any prevention against 51% attack has to be implemented such that it's effective against all possible 51% attacks(which you have to do  anyway if you can), to just target a particular group of people is ridiculous.

They would do it as closely together as possible. They're unlikely to connect one machine at a time to the network.

It's an example of a nation. But yes, it could be any nation with enough resources.

Exactly, so it's not related to how many nodes are, or even how much hashpower is in China, right?

Not to say a 51% attack can only be pulled off by a single node with 51% of the hashing power, not a lot of nodes combined together.

So what OP said is not relevant.

The OP asked a question. So it's as relevant as a question can be.

What I said is relevant: "A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed."


Title: Re: 51% attack possible ?
Post by: oakpacific on May 20, 2013, 02:33:52 AM
Or they could just muster the resources and do it anyway, with no warning.

No unusual mining power growth can escape people's attention, you get the most paranoid bunch of guys in the world here, why bother with additional resources?

And it's not even relevant, any prevention against 51% attack has to be implemented such that it's effective against all possible 51% attacks(which you have to do  anyway if you can), to just target a particular group of people is ridiculous.

They would do it as closely together as possible. They're unlikely to connect one machine at a time to the network.

It's an example of a nation. But yes, it could be any nation with enough resources.

Exactly, so it's not related to how many nodes are, or even how much hashpower is in China, right?

Not to say a 51% attack can only be pulled off by a single node with 51% of the hashing power, not a lot of nodes combined together.

So what OP said is not relevant.

The OP asked a question. So it's as relevant as a question can be.

What I said is relevant: "A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed."

Every word in your sentence I agree except the "significant risk" part.

OP asked the wrong question because 51% attack has hardly anything to do with the total hashpower within a nation's border.


Title: Re: 51% attack possible ?
Post by: BitcoinAuthor on May 20, 2013, 02:40:27 AM
Or they could just muster the resources and do it anyway, with no warning.

No unusual mining power growth can escape people's attention, you get the most paranoid bunch of guys in the world here, why bother with additional resources?

And it's not even relevant, any prevention against 51% attack has to be implemented such that it's effective against all possible 51% attacks(which you have to do  anyway if you can), to just target a particular group of people is ridiculous.

They would do it as closely together as possible. They're unlikely to connect one machine at a time to the network.

It's an example of a nation. But yes, it could be any nation with enough resources.

Exactly, so it's not related to how many nodes are, or even how much hashpower is in China, right?

Not to say a 51% attack can only be pulled off by a single node with 51% of the hashing power, not a lot of nodes combined together.

So what OP said is not relevant.

The OP asked a question. So it's as relevant as a question can be.

What I said is relevant: "A government attack is a significant risk. Think about China: they have the resources to pull off the heinous deed."

Every word in your sentence I agree except the "significant risk" part.

OP asked the wrong question because 51% attack has hardly anything to do with the total hashpower within a nation's border.

Fair enough. We have different ideas of the risk. I obviously agree with my own statement.


Title: Re: 51% attack possible ?
Post by: EBM on May 20, 2013, 12:58:49 PM
The odds of a 51% attack on any particular day are not zero.

BTC community should therefore be prepared for it, because unless those odds become zero it will happen eventually.

Crypto currency has this one problem: it can be destroyed by a malicious 3rd party with sufficient resources. However small that risk is, it's not small enough.

For all the problems of regular currencies, they are very old and refined systems. Think of them as v1649.37 or something like that. Compared to BTC, normal currency has loads of checks and balances and is backed by huge institutions (ie. entire countries). The US dollar might slip and slide sometimes, but it's never going completely under.

BTC, on the other hand, is a completely new system with a well-known flaw that can actually destroy it completely (!) - the likelihood of which no-one really knows.

v1.0 of the Death Star looked impregnable too.


Title: Re: 51% attack possible ?
Post by: qxzn on May 20, 2013, 11:12:31 PM
I am more concerned about a nation-state performing a difficulty attack (https://bitcointalk.org/index.php?topic=210900.msg2216328#msg2216328) than I am a 51% attack, though I hear with a mere 51% there may be a shortcut (https://bitcointalk.org/index.php?topic=74126.0).


Title: Re: 51% attack possible ?
Post by: BTCLuke on May 22, 2013, 09:13:30 AM
I just laid this question to rest on my blog here:

The Futility of a 51% attack (http://bitcoinfinger.wordpress.com/2013/05/20/futility-of-a-51-percent-attack/)


Title: Re: 51% attack possible ?
Post by: EBM on May 22, 2013, 11:31:24 PM
I just laid this question to rest on my blog here:

The Futility of a 51% attack (http://bitcoinfinger.wordpress.com/2013/05/20/futility-of-a-51-percent-attack/)

"This would now require far more money to invest in hardware than most countries’ annual GDP."

No, it wouldn't. It would require approx $60m-worth of ASICs.

To any bank or Govt, that's chickenfeed.


Title: Re: 51% attack possible ?
Post by: JamesTaylor on May 23, 2013, 12:05:53 AM
BTC Guild is the first not interested in a 51% (>50% to be precise) control, since all their work would devaluate, so I think it's not going to happen, at least not why the source is public. It's fine while we know where more than 50% of the blocks come frome.


Title: Re: 51% attack possible ?
Post by: _mr_e on May 23, 2013, 12:13:01 AM
https://i.imgur.com/QLxeqGm.png


Title: Re: 51% attack possible ?
Post by: BTCLuke on May 23, 2013, 12:40:39 AM
I just laid this question to rest on my blog here:

The Futility of a 51% attack (http://bitcoinfinger.wordpress.com/2013/05/20/futility-of-a-51-percent-attack/)

"This would now require far more money to invest in hardware than most countries’ annual GDP."

No, it wouldn't. It would require approx $60m-worth of ASICs.

To any bank or Govt, that's chickenfeed.
Admittedly I derived that amount by assuming they'd try to add more (non-asic) servers to the task... I doubt that the'll get with the program enough any day soon to put together their own ASIC-making plant and mass produce them themselves.

One thing we have going for us in that department is that we're already tapping out the max production facility of all ASIC manufacturers and the free market on these products that basically print money will assure that it will stay that way for a very long time.

...So on top of that $60m worth of ASICs, they'd have to foot the larger bill of R&D for their own ASIC line, and then the manufacturing facility to make them... So perhaps closer to a Billion, I'd think.

Of course uncle sam could afford that too, so I'm more depending on the fact that this community has shown that it has a reset button for bitcoin to dissuade them rather than the hardware itself.


Title: Re: 51% attack possible ?
Post by: EBM on May 23, 2013, 12:12:23 PM
I just laid this question to rest on my blog here:

The Futility of a 51% attack (http://bitcoinfinger.wordpress.com/2013/05/20/futility-of-a-51-percent-attack/)

"This would now require far more money to invest in hardware than most countries’ annual GDP."

No, it wouldn't. It would require approx $60m-worth of ASICs.

To any bank or Govt, that's chickenfeed.
Admittedly I derived that amount by assuming they'd try to add more (non-asic) servers to the task... I doubt that the'll get with the program enough any day soon to put together their own ASIC-making plant and mass produce them themselves.

One thing we have going for us in that department is that we're already tapping out the max production facility of all ASIC manufacturers and the free market on these products that basically print money will assure that it will stay that way for a very long time.

...So on top of that $60m worth of ASICs, they'd have to foot the larger bill of R&D for their own ASIC line, and then the manufacturing facility to make them... So perhaps closer to a Billion, I'd think.

Of course uncle sam could afford that too, so I'm more depending on the fact that this community has shown that it has a reset button for bitcoin to dissuade them rather than the hardware itself.

ASICs are just chips. VAST production capacity is out there. And the $60m figure includes the chip design - do you really think Avalon and ASICminer spent a billion dollars on R&D?

Hell, buy one of their chips and clone it. Job done.

And sorry to dent your optimism, but a 'reset button' is only helpful when it doesn't have to be used 100 times per week...