Topic: The invulnerabe Bitcoin myth. (Basic math risk analysis) - page 2. (Read 3432 times)

Your new transaction would be unconfirmed. The transaction can be resent and your attack would be rejected. You can make another 51% attack, but the odds of being successful depend on variance.

Bitcoin can be defined as larger than the top 500 only if you decided to measure power by the amount of one of the most basic form of calculation almost nobody has use for.

What do banks and military agencies use their processing power for ? Competitive advantage.
So you think they'd show they card to everyone ?

I won't bother calculating this but take the profit of one week at 2 Ths and dump it every sunday to see where price would be.

What news ? There would be no obvious way to know.

I agree with everything you said aside from your uber optimism.
I still don't like the idea of having the future of Bitcoin at the mercy of an old fart billionaire or bureaucrat needing "a compelling reason" to spend 2M$ "to mount a 51% attack"

You forget saying that the 500 computers are made out of CPU, that have big memory and caches too, not of GPU  

Comparing cpu with gpu is fail, they are 2 very different thing.

It seems to me that the most damaging thing about a 51% attack would be psychological.  And that if it happened once, it might be able to happen again and again.

I personally am not to worried about a loss of hashing power due to a BTC value collapse and loss of interest, and a subsequent 51% attack.  It seems to me that a viable Bitcoin system could run fine in a fraction of today's hashing power.  There would have to be a compelling reason to mount a 51% attack and some significant coordination.  Promising some mining pool a bunch of  scamcoins in trade for their cooperation a) probably would not be sufficient motivation, and b) word would get out and a lot of miners would likely not cooperate or switch sides to actively support Bitcoin.  Probably a fair number of them would fire up their idle rigs to protect their BTC hoard.

In a truely crazy world where TPTB somehow gathered enough hashing power to attack Bitcoin successfully on an ongoing basis, there would always exist a 'nuclear option' of changing the code and getting users to upgrade (which seems to be what you are alluding to to some extent.)

51% attack is 100% control of network.  You can do a lot more than just delay transactions.

For example I buy 100,000 BTC coins from you.  51% and replace that transaction with one where I sent those coins to another address I control.  You see 100,000 coins disappear from your wallet.

I am not too worried about a 51% attack.

A 51% attack endeavors to create blocks without including valid transactions, right?  Either that, or to give us blocks full of spam.

I believe the client should have a means to resubmit an unconfirmed transaction to the network with a transaction fee, or a higher transaction fee, with the network accepting the new transaction as replacing the old one.  This would allow anyone whose transaction doesn't stand out from the spam - or which miners don't seem to want to touch - to get their transaction reprioritized.

With that, any logic added to the client code that ignored blocks that clearly appear to avoid containing valid highest-priority transactions more than a minute or two old would ignore the very blocks an attacker would create.  That could very simply make a 51% attack far less disruptive.  A 51% attack might do little more than exert upward pressure on transaction fees for those who want their transactions confirmed, rather than cripple the network.

Anyone care to refute this crazy thought?

I see it somewhat different. Why would the banks destroy it, when there's an opportunity to profit from it? The biggest game in town--housing--bubbled and burst. They (the bank(er)s) are always looking for ways to manipulate their un-fellow man. If China can do it with mining WOW by their prisoners, surely embracing Bitcoin in a creative fashion could reap tremendous rewards.

The establishment knows not to piss off hackers by challenging them on technical grounds: that tends to yield the exact opposite of the desired outcome.
It is much easier to attack the weak points: communication and public relations.

Look, it makes things easier if we believe that with a large amount of money comes potential evil. To portray coin dumping as a nuclear bomb keeps the world-view in tact. It would be much easier for people's psyche if we keep things that way.  If you're wealthy, you're evil unless you endorse eugenics or are Micheal Moore.

Bingo.

I don't see the 51% attack as the weak point of Bitcoin. Establishing an alternate block chain requires more skill than just acquiring the majority of computing power.

The biggest threat to the establishment lies in doing business exclusively in Bitcoin and taking away the banks' precious fees and interest payments on the debt. When small / large business sees that they can save $X M per year in fees, and when consumes are actually able to buy something (in a store) with coins, that's when the real attack begins.

I don't think that the Congress and equivalent ruling bodies of nations have enough foresight to stop this sort of legitimate threat to the coins of the realm.

Man... almost every day has far more than 7,200 coins sold on the market. Many of these coins are from the mining already. Even if a nefarious entity mined every single coin and sold it, that wouldn't have a lasting or seriously detrimental effect on the market price.

And come on... if a news story like that broke?!  You instantly have a million people around the world suddenly interested in this stuff. Price would not collapse I assure you.

More dangerous than dumping the mined coins is simply manipulating the network with the majority hashing power issue. That's still a legitimate, if unlikely, concern.

a: The gov/banks already have/use more computing power than the whole Bitcoin network.

Nope.

b: They can, in a matter of months, purchase the additional equipment required for a 51% attack (5 Thash/s) for 2 500 000 $ or less, (333mhs@165$), (with consumer GPU, not even ASICS)

Hah. No, here's what will happen. A contractor will come along and say he can do it for 50 mil, alright, with 20 for him and 20 for the other guy and maybe -- just maybe -- 10 mil for the inefficient bureaucrats to do the actual job. People will sit on their asses and twiddle their thumbs while pretending to do the project, then they'll have something horribly obsolete in 2 years or so.

Maybe the banks will do a better job discreetly but I doubt it. They would probably rather destroy bitcoin through FUD. Anyways, don't overestimate a farce of bureaucrats and corporate puppets we call the government. They can hardly do anything right without destroying more wealth along the way.

Your numbers are wrong.  Not going to waste any more time on them but "the banks" (there is no such single entity) don't have more computing power than Bitcoin.  Bitcoin is larger than 500 largest super computers combined.  

As for a billion dollars.  LOLZ.  Nobody said Bitcoin is invulnerable.  Today it couldn't survive a $1B attack, it also couldn't survive a nuclear holocaust either.  Not many things (hell even countries) can survive a determined enemy w/ $1B budget.

If Bitcoin is large enough to warrant a $1B attack then it is large enough to have the hashing power to survive one.


At least take a slightly less nonsensical stab then $0.5 per MH.  Show me the rig you can build (everything including warehouse space, cooling, power distribution, networking, racks, MB, CPU, RAM, GPU, labor, maintenance, administration, security (you going to leave $20M+ worth of gear unguarded) for $0.50 per MH.  I would like to see that rig.

To all people minimizing the threat from the establishments,  / topic "Guy admits it is his job to destroy Bitcoin."

What is required to keep BTC working and safe from a 51% attack  ?
1, Transistors  2, Electricity 3, Balance of power

1. Chips cost money
2. Electricity cost money
3. Money is very unevenly distributed.

Have you ever heard of the CIA cracking password, ?
Have you ever heard of banks using GPU/FPGA to predict markets ?

a: The gov/banks already have/use more computing power than the whole Bitcoin network.
b: They can, in a matter of months, purchase the additional equipment required for a 51% attack (5 Thash/s) for 2 500 000 $ or less, (333mhs@165$), (with consumer GPU, not even ASICS)

Dumping their earned coins on the markets cause the price to fall and make mining unprofitable.
... Feedback loop...
The hash-rate is rising while the price is tanking.

It may not be happening now but the risk is really there.

I think very few people truly realize how small the Bitcoin market is in comparison to the pocket of those who want to keep full control.
A handful of people would spend Billions on that.

Taking a 1 billion $ figure, a 51% attack could happen even if hashing power was 1000x what it is now (yes, 8 Peta hash/s).
(300$ per ghs, with 2011 ASIC technologies)

Ps: Please do not respond only to correct my maths, these are very rough estimate.