Topic: How much would it cost right now to attain 50% of the network? (Read 5023 times)

Even if they cared enough to gain 50% of the processing power before it is able to become more mainstream, that doesn't mean Bitcoin would be broken. They may make life difficult for us, at least for a while, but I feel that either Bitcoin would adapt or some other crypto-currency would take it's place.

The funny part is that bitcoin is supposed to be immune from governments... when in fact it is most vulnerable to governments. Governments can requisition more FPGAs than the public by far. Most people don't have massive GPUs in their laptops, how is this in any way decentralized?

Everyone who owns bitcoins got them by investing real money in specialized hardware. It's a joke.

LOL if you have money you can do anything you want.

For all I know the gov. is watching and infiltrating this community and evaluating what to do from now on.

The Bitcoin thing is a threat to national security and according to the dumb patriot act you are all "terrorists".

Bitcoin is untaxable, used for drug dealing / weapons etc. so they can find all of these reasons to take it down etc.
Drugs are untaxable and that is why they are illegal and cracking down on them etc.

The government likes control. Bitcoin = less control.

This unfortunate day will come but some people here seem to think that it will not happen. I assure you it will, not that I want that though, don't get me wrong.

All you're saying is that they have lots of money and some computing power. That does not fulfill all the requirements necessary to "take over" the Bitcoin network.

LOL are you joking ?

This whole gimmick network can be taken over pretty quickly.
 
Do you really think that the US gov. could not defeat some gamers in their basements with ATI cards etc. !

Military technology is years ahead of that available to mere civilians. The NSA are talking about building exaflop computers already etc.

Not to mention a huge budget of billions of dollars. Geeks will never match that.

Even the Chinese have them ( http://en.wikipedia.org/wiki/Tianhe-I#Tianhe-1A does about 4.7 petaflops and bitcoin has about 25 petaflops total hashing power ) ! Keep in mind that all this is released to the public but behind closed doors they have supercomputers that are for the military and many times ( 10x even ) stronger than what universities have etc.

LOL again !

Don't just say they can, tell us how.

Come on people don't be fooling yourselves. Some government agency could bring this whole project down in the time it takes to generate a block ( roughly ten minutes ).

If deepbit.net can do it then the US gov. or even somebody like Google can mess this up pretty quickly and make it unprofitable in a second.

Exactly what I was trying to get at... you just beat me to it 

Now, if he controlled all this power himself, people would be able to see that something was going on, but would be powerless to necessarily stop it since he would be able to validate his own fraudulent transactions.

The difference with deepbit versus a single entity (government, rich prince, etc) is that deepbit does not own it's computing power. It is at the mercy of those that give it to it. And, people are a fickle bunch. If anyone even slightly suspected that deepbit was up to no good, that could adversely effect any evil plot it's operate may or may not have.

And... as far as "since it would be impossible to catch him doing it... i think people would have to assume that he is"... there is a sentiment of supporting other pools just to keep things balanced.

No, it's not impossible to catch. In order to "steal" coins, he would spend them on some item or service and wait to receive it. Once he did, he would direct deepbit to build not from the current block, but the one prior to the transaction. It would have to generate all of the blocks that have passed since and surpass the length of the current chain, at which point the transaction would be erased, giving him back his coins.

It would be fairly obvious this was occurring, and all of his miners would jump ship, because it is not in their interest to take part.

why would deepbit not steal bitcoins if he has 50%?

since it would be impossible to catch him doing it... i think people would have to assume that he is

deepbit has nearly 50% and it doesnt cost him a dime. it makes him money

The network currently is about 2,000 Giga hashes at max.

It costs about $1 per Million hashes of computer power (for decent quality parts). 1000M hashes = 1 Giga hash.

You would need basically 1000, $1000 dollar computers.  Total cost would be about 1 Million dollars would do the trick JUST for computer hardware.

Now if you didn't already have a facility to keep the computers, I imagine that would be in 100's of thousands or even a million or two for a data center capable of running that many computers.

Or one could potentially be leased.  I would say the minimum upfront cost to control over 50% of the network would be around 1.5M dollars.

Assuming that $2-5 million would get you >50% of the network's computing power, you would be able to reverse your own transactions. There are other potential attacks that would require more or fewer resources and more or less luck, but double spending is the main threat of a computing power takeover.

They can...

Maybe someone could take it over for that amount, if done today. However, there exists a fortunate dynamic in that such an attack only becomes more likely to the extent that the bitcoin economy grows. And, to the extent the bitcoin economy grows, it becomes increasingly harder to take it over.

This is a wonderful natural defense mechanism of the system... the more attention it draws, the more dangerous people may want to attack it, but then the harder it is to attack. By the time the "bored Saudi prince" discovers this whole thing, perhaps it'll be too expensive for him to intervene. Here's hoping, anyway =)

No, you are right... but I don't think the electric bill is a "big concern" for someone willing to spend over $2 million dollars (just in hardware) to "hack" a digital currency. I was mainly looking at this from a perspective of "what if the a government wanted to control Bitcoin" perspective....

So can someone tell me how this doesn't mean that someone w/ $2-5M can take over the entire BTC economy?

Your math also doesn't account for secondary costs. Aside from the 2 million USD of hardware (assuming you can find 1,628 5970s in short order, no small task), 407 machines running 1,628 GPUs would likely eat roughly 610 KiloWatts of power, requiring 5,087 Amps (or if you were on an industrial power grid 2,543 Amps). Either renting out expensive space at a data center or building a custom housing/generation complex would be required. Additionally 610KW = > 2Million BTU/hr, requiring some form of cooling to the tune of being able to remove 2 Million BTU. Custom networking and so on.

It obviously wouldnt be tens of millions more but there are lots of additional costs to running huge farms of machines.

That makes sense, thanks 1bitc0inplz, very interesting

I guess there are a few reasons someone with a few million dollars to burn might want to do this.

1. They have a vested interest in conventional currency. Think Mises.org conspiracy theories about international bankers who would see bitcoin as a threat to their economic domination.

2. A government decides bitcoin is illegal (esp because people aren't paying taxes!) and chooses this form of technological force to shut it down since conventional force is not sufficient to enforce the law in this case.

3. A malicious and bored millionaire just wants to do it for fun, to see if he or she can.

4. Someone thinks they could make a profit by sucking up all the bitcoins. Considering that people of limited resources are currently investing thousands of dollars in bitcoin speculation, maybe some angel investor with a billion dollars thinks this is a fun way to diversify his portfolio for a few millions.

5. A bored Saudi prince decides this is more fun than buying another private jet.

It would be interesting to see if someone could compromise the currency while still maintaining public confidence in it. That could be very profitable.

It seems to me that a currency which can be compromised by only a few million is on a precarious basis. How can the public really have confidence in a currency that may, unknowingly, be completely compromised by powerful established interests? I mean who is to say that the NSA has not already drawn up a project to cripple bitcoin? ~$2million to the NSA is utterly nothing. And, if we're being honest, they already have the hardware hooked into the net to do it. So it would likely be more of an opportunity cost issue rather than buying up the hardware.