This thread demonstrates why bitcoin is a joke and always will be.
You people flock to bitcoin supposedly to reclaim public, distributed control over a currency, and then you just give away the power to the first pool operator who asks for it.
What a joke.
The fact that people are actually arguing here that "deepbit would never do such a thing" is unbelievable. Is he Jesus now? Is he your new guru? I thought the entire point of bitcoin was that no one would be the guru, no one would have control.
And then you have the incredibly naive and ignorant argument that if someone abused the network people would "rally" to save it. What fantasy world is this? That's not what would happen. People would abandon the currency because they don't want to sink more money into a flawed concept and flawed community.
Amateur hour. The fact that one man already actively controls enough cryptographic power to break the validity of the currency with NO OVERSIGHT and people put their BLIND FAITH in him..... no serious person is going to have confidence in the currency when they learn that the exact exploit conditions presented by the creator have already been fulfilled, and not through investing significant personal resources either, but fulfilled because bitcoin users VOLUNTARILY GAVE AWAY their cryptographic authority to him. Amazing!
For the record, the attack is technically possible at > 50%, but to make any real amount of return on implementing this attack would require a significantly greater percentage as it would be noticed rather quickly if the attacker was only able to build a new chained block that is longer than the original at slightly faster than the rest of the pool. As we know, however, knocking out another large pool, as happened when Slush went down last weekend or so, resulted in a flood of people into deepbit and a huge spike in hash rate, so being at 50% or so already (hypothetical case) and taking out a 30% pool with say 2/3 of them going to deepbit [considering the number of pools that exist today], that would put deepbit at 70% making it a huge threat for attack. I do not think Tycho would do this as he is making a lot of money the way it is and destroying a revenue stream for a one time gain and somehow cashing out or spending the coins would not be beneficial for him. More likely is a remote attacker taking over the pool. I am glad measures are being taken to to avoid such an attack [by at least a few pools], but there are those out there, with enough motive, that will eventually attempt it in all likelihood given the opportunity [which is the subject of this thread].
The point of this post; an attack would not in all likelihood destroy the bitcoin economy, but it would damage it [trust would go down and apparent risk would go up and thus prices would drop]. Many people would lose funds they thought they had from the pool used for the attack, but it would be distributed, so it is probably less likely to destroy the market as destroy the pool that performed the attack [nobody would use the pool again if it had been used as a weapon for theft]. Worst case is that people would go back to solo mining making the growth of network hashing power slow or even reverse [which might be a good thing] and virtually eliminating the threat for the future. Pools are only dangerous if used as a weapon [although they are drawing in a lot of hardware causing a "waste" of a lot of electricity that wouldn't be as great with solo mining ... many simply wouldn't solo mine]. I want to see bitcoin do well and I do not want to see such an attack ever occur and I am pretty sure that the pool operators don't either [kills their revenue stream]. Consider how fast they would have to "rechain" multiple blocks without detection to get a large loot.
Solution? Not sure if feasible, but if some sort of pool existed that itself was a member of all other pools and watches out for duplicate base block data to come through as shares of work then it could be detected rather quickly. Problem .. it would take a large central database at this pool and it would cost significant money to maintain it and have the ability to compare work to past solved blocks. I don't know if it could be profitable [and it itself could still be cracked ... but we trust banks, for the most part, with our fiat money, so there has to be some level of trust].
Let me pose this. What would pool users do if ALL pools except one went down over the course of a few hours or minutes? Would they jump to the one remaining pool? Now suppose that all but the largest pool went down; would they still jump to the one remaining pool? That is where pool miners need self control [and it is proven by history that they do not have it currently when one large pool goes down]. Honestly, I think all users should setup an alternative configuration to switch over to solo mining in such a situation or simply just temporarily shut down. Do the people have the will?
Essentially, I think the risk to bitcoin isn't huge in the long term if such an attack were to take place, at least not if it takes place with the market at it's current size or a significantly larger size. A potentially costly solution could keep the pools monitored and potentially offset some of the costs by paying enough miners to support it by doing the work pulled from the pools being monitored [probably not feasible, but an idea ... pool operators would payout the monitoring pool of course], and last, miners need to control their emotions and greed to avoid and stop an attack when discovered [if not too late] as I indicated. The potential for attack and damage from it is real, but the end of bitcoin from such an attack is unlikely.
If you read this far, congratulations
Eventually, if this project turns out as well as expected, some larger merchants are going to get in on the currency, but that is going to require brokers to handle transactions [i.e. reversals for fraud], and accountability of these merchants to their respective government(s) for taxes. In fact, this could already be an issue for some (I bet most people are net negative from hardware investment or barely positive, so taxes are probably not an issue for most ... yet). Converting to fiat currency leaves a trail for the tax collectors to go after I think. Keep receipts for your hardware and electricity investment [hobby income in the US is taxable only when profits exceed expenses of the hobby].
Be safe.