Why does people keep comparing mining with supercomputers? Supercomputers have petabytes of hard disks and terabytes of ram memory, totally useless for mining. Supercomputers are a network of thousands of cores, totally useless for mining. And so on. The today fastest supercomputer (top500.org) has approximately 300 000 opteron cores and 19 000 tesla cards. CPU and nvidia mining so. No wonder they would epic fail at such attack! It becomes instantly useful again the moment the attack ceases. If it ceases. The attack will stop if legitimate miners can upgrade their equipment faster than the government does (which the government has to constantly pay for). Also, I didn't know the government got free electricity. Government can print money at will, hundreds of billions of dollars printed at will. They "pay"? Electricity is not "free"? Lol. They spend so many billions every year for war and now they can't even spare 20-30 millions for a 51% attack? Double spends can't be fixed by reverting to a back-up blockchain Every block created during the 51% attack obviously can't be trusted. So you must revert to a backup blockchain. And yes, they can be reverted |
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In practice it's impossible to rewrite 1 year of blockchain faster than the honest network in hope that will become the longest chain and replace the legit one. Even if you're hashing your blockchain offline you must obey the rules of the protocol which means that the difficulty will update each 2016 blocks (up to a maximum of 4 times the previous difficulty if i'm not mistaken). Even if you're using processing power orders of magnitude higher than the honest network the difficulty will catch up with your hashrate leaving you producing blocks at the same average (around 10 min each) and your blockchain will never ever catch up.
As other said, the "longest" blockchain is the one with the highest difficulty, not the one with more blocks. 1 difficulty 100 block is worth 5 difficulty 20 blocks |
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Excuse me but why are you basing it on sha3? Mining uses sha2...
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The amount of computing power it would take to get to ten percent is astronomical at the present No, 20-30 millions $ and you can do such attack. It is beyond any combination of the three (probably more) highest performing supercomputers in the world at the moment The fact that the supercomputers are build to do OTHER things is why they aren't good at mining. Some supercomputers are made of nvidia cards, everyone know that nvidia cards sucks at mining but probably they excel in what they have to do in supercomputers. which gets very expensive For us normal people. Not for a government, corporation, bank, other powerful entity. |
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I guess in order to actually disrupt the network, you would need to crowd-out most transactions, so you would need to consistently mine several blocks in a row, not just 1 in 2. So, even if you get say ~80% of the network power, Bitcoin could still be usable as long as the blocks are normally less than 20% full (and all the transactions can be crammed into 1-in-5 blocks).
Couldn't the attacker just invalidate previous "correct" blocks with transactions by not including them in their (longest) chain? Yes, he can I don't know. Maybe you're right. At this stage I think it's a moot point though -- why destroy Bitcoin when you can control it? And why advertise your power and risk losing everything?
Because you can't print bitcoins at will like with fiat money. They want to protect their power to print money at will and defend their privileges. Destroying bitcoin does this and about losing... what, some millions of $? They have hundreds of billions! |
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A good idea. No point in joining a pool with higher fees!
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Thank you guys,  Is it because of the elliptic curve cryptography that makes GPU mining favourable then? Sha256 hashing. It is heavily parallelable, you can have a GPU hash thousands of different numbers together, each hash is indipendent from the other one. And it happens that GPU excel at parallelable tasks (and sucks at problems where you can do the next operation only after you know the result of the current one) |
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Except what you are saying, and what you are actually talking about are completely different and have nothing to do with who has how many coins.
He is a bit confused, but he is right when he says that a government has tons of money and CAN make such attack. The 51% attack cannot "collapse the whole system" Yes it can, with a 51% attack bitcoin becomes instantly useless. They can only fraudulently reverse or modify their own transactions, not anyone else's. They can (temporarily) prevent other people's transactions from being confirmed, but not modify them in any way or reverse transactions which were already confirmed before the attack What? With a 51% attack you can replace the current blockchain with your! And that blockchain can for example start being modified since a year ago. This means that since a year ago all the blocks were found by the attacker. This means that he own all these bitcoins and that no other transaction has been confirmed since then. You mined your coin 6 months ago and spent them? No more, he mined these coins! Not you! So your transaction disappear. It never existed. cannot create coins out of thin air True the attackers can only do anything during the time they are actively mining with 51% of the hashing power This rely on your hope that the attack eventually would stop. Why it should? After a government start the computers, it can leave them attacking for whatever time it want! Yes, if the attack stop then we can fix everything (lot of people keep a backup of the current blockchain). But that is a big if! |
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Yeah, ridicolous. Fail article  "authorized" lol. |
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I would change how mining is showed, yes it is important technically but bitcoin is no more a "you mine with your computer" thing. We are in 2013 now, mining today is about ASICs. When they speak about paypal they don't explain you how their servers work, how their software manage everything etc. Same for bitcoin, it is ok showing how bitcoins are generated, but in a different way
And yes, remove or change the alpaca socks reference. Today you can buy everything with bitcoin, two years ago you could buy only alpaca socks. So maybe say something like "you can buy this, this, this, this, also this and also alpaca socks!"
Then we have the problem about the client. Suggesting the qt client to new ppl is suicide, days to get the blockchain, it takes minutes to open when you launch it and the interface sucks. I would definitely suggest a lightweight client, together with the qt client.
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Well you need a mod to whitelist you or 5 posts and some hours passed on the forum
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ASIC arrived yesterday. Case closed.  |
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This is starting to remember me the 2011 bubble. Only that back then we were at 1$, not 20 |
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21$  |
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Meh, it is just because it's a thing downloaded often.
Interesting info eleuthria, didn't know these things. Well, with ASIC mining these botnets will become soon mostly useless, or anyway, they will see their profit reduce dramatically. As for ddosing, luckily we have p2pool.
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Wow, a virus miner. So bot mining really exists. I wonder if it was a cpu or gpu one...
Well, welcome in the bitcoin forum, get rid of that virus!
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You must buy ASICs. GPU mining died the instant the first person received his ASIC  |
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Fifty one percent of the network hashrate is then approx ~ 14,321,310 Mhash/sec Nonono. This is wrong. The 51% attack means that the attacker has the 51% of the power. Your attack would fail. Current power: 28. You would then have 14. Final power: 28+14= 42. You would only have 33% of total power, not enuff. For a 51% attack you need to have the same amount of current power. So, at least 28. (meh yesterday it was 21thash, not 28 lol) A 6990 is expensive, two 7950 costs like 400$ and do more than a 6990. The argument that the government is slow, inefficient and won't spend so many money (40 millions a lot? lol) doesn't makes sense, just look how many billions they spend in military, if they notice that bitcoin CAN be a threat to their existence (>and to their epic money printing) they will act quickly, very quickly. Also a bank or whatever other financial organization can do such attack. Yes, our hope is that we are too small, but right now we are growing, and a lot. (note that the fact that they can print money out of nowhere means that the cost of this attack don't really matter to them) |
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This thread: lol |
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