What would happen to me if I have a possibly tampered Bitcoin client and a network with more malicious nodes than honest ones?
This would count as forking the chain. A normal/honest client simply wouldn't accept any chain other than the one with the official checkpoint. Also with PoS what's really important is only the developer's signature, however many people you have to sign the checkpoint it's only the client signature validating them to be true.
Again, the signature for the checkpoint was just a convenience. It just saved downloading an updated client. A better way to think about it is that there are 2 clients. The "beta" client is a POW based client, but it won't accept any blocks after 70000. Once 60000 blocks have been found, then 50000th block becomes locked in and a brand new "release" client is created. The new client has the 50000th checkpoint hardcoded. This is no less vulnerable than bitcoin, which has the genesis block hardcoded. If someone sends you a client with a fake genesis block, then you will mine on their (fake) bitcoin chain too. The only POS coin running at the moment has a developer based checkpoint system to prevent roll back, but that isn't strictly required. They could certainly send me a fake chain, but it would took them more than millions to convince me if I simply check the difficulty. The whole point of Bitcoin as stated in Satoshi's paper is voting by IP doesn't work, malicious nodes shouldn't win just by numbers. |
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i was under the impression that they only had a personal account. have they had the business account all along?
All along, they used both accounts for a while. |
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Then there must also be some authoritative, central places for distributing the client as well, these sites have to stay up and running as long as the network is, when billions of dollars are at stake or the governments get involved I don't think they will hold up so well.
That is true for bitcoin too. The point of signing the checkpoint is so that v1.0 clients will accept blocks after the checkpoint time. The software could simply be set to refuse to accept new blocks after a certain height. This would fork everyone to update at the same time, which has security implications. There is no difference between having the dev sign a new client and simply sign the checkpoint. Signing the checkpoint used up much less bandwidth. Once the checkpoint has been passed, all clients, from the original dev or others, will simply hardcode the same checkpoint for the 50,000th block. The checkpoint is part of the protocol. What would happen to me if I have a possibly tampered Bitcoin client and a network with more malicious nodes than honest ones? I can always only give the client only the key for a test address, with a very small balance(which I got for free, say from a faucet) for a test transaction, then I will check all possible third-party soruces for the newest raw blocks(e.g., blockexplorer.com) if my transaction is mined, and have them verified locally using a random SHA256 implementation to see if these blocks truly meet a certain difficulty target. If they collaborate against me then it's not going to pass, if not then I have the real newest blocks and I can tell which nodes are honest to me, the worst outcome is I will lose my test coins. If I use a PoS coin, then if I have more bad nodes then good in the network, a possibly tampered client, and all third-party sources collaborating against me I probably have no way to tell if I am getting the right chain, after all the first 50,000 PoW blocks are easy to forge after a few years with Moore's law. Also with PoS what's really important is only the developer's signature, however many people you have to sign the checkpoint it's only the client signature validating them to be true. |
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also the developer may have difficulty proving himself to be the...developer without an external authority, similar things happened in the countless cases of internet scams.
The developer would just hardcode his public key into the software. The client could just check that the message is signed by him. In practice, it would be better if there was multiple people with the keys. Those people should be trusted and distributed over the planet (for protection against court orders). The checkpoint would have to be signed by M of N of them. For example, there could be 9 public keys hard coded into the client at lauch and the checkpoint has to be signed by at least 6 of them. Then there must also be some authoritative, central places for distributing the client as well, these sites have to stay up and running as long as the network is, when billions of dollars are at stake or the governments get involved I don't think they will hold up so well. Yeah Bitcoin uses checkpoint too, but as you have pointed out with a "headers-first" approach we probably can get rid of that, and I can even download the blockchain and check the difficulty first using torrents, without connecting to any node. |
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Thanks, so they can't get rid of that "trusted/centralization" part right?
It is just a once off thing. A better way to think of it is that the POW stage is an initial "fair" giveaway stage. Once it is done, the checkpoint is part of the protocol. The chain is defined as having a particular hash as genesis and that block 50000 hashes to <checkpoint hash>. The only difference is that it takes a while to find the 50000th block. If you joined after the 50000th block, there is no difference between the hard-coding the genesis block into the client (which Bitcoin does too) and hard-coding the 50000th block. It is fully p2p after the 50000th block. Ah, I see, so no mining will happen after the 50000th block right? The only way to get any coin afterwards would be to obtain from those who already have it? Also your ISP maybe playing con tricks on you and you never get the right checkpoints There is only 1 checkpoint and it has to be signed by the original developer (or group of trusted individuals). They promise to only sign one checkpoint. The ISP can't fake that signature. The checkpoint signature would be part of the protocol. They can't really stop you from getting the signature. It only happens once, and they would have to scan everything that goes to you to block it. This would require blocking you from making any encrypted connection at all. That isn't feasible. While hardcoding in the Bitcoin client remains the status quo, I would have no problem telling a fake chain from the real one without such hardcoding, as I could always check if the difficulty of the newest blocks meet the right target, assuming no one is attacking me with a hundred million-dollar farm of course, it is on the other hand much easier to just change the content of a software as the cost for hijacking a communication channel is much lower, also the developer may have difficulty proving himself to be the...developer without an external authority, similar things happened in the countless cases of internet scams. |
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PoS is centralized, you can't even tell a fake chain from a real one without using checkpointing.
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I haven't really taken time to look into PoS, but it sounds extraordinarily stupid to me: if I were a botnet operator who insert millions of nodes into the network to broadcast my fake PoS blockchain, which can be easily made because there is no requirement on the amount of work, how do you know which chain is real? Also what if several people controlling large stakes are kidnapped and forced into give their private keys?
PoS needs some kind of boot-strap. Most of the current systems are hybrids. PPCoin has POW and POS blocks. They aren't exactly clear on what their system is though (at least last time I checked). You can get a mint reward by finding a POW block and you can get a POS reward by consuming coin-age. When comparing 2 forks, only POS from before the fork should be considered. If the fork point is at the genesis block, then POS cannot be used to distinguish between the chains. A release strategy for a "pure" POS coin might be - coin starts as a POW coin - assume 50,000 blocks per year - after 60,000 blocks have been found (14 months) -- snapshot the 50,000th block as a checkpoint -- release new client with that checkpoint hardcoded -- broadcast checkpoint digitally signed by devs/trusted people (N of M rule) - after 70,000 blocks have been found (17 months) -- initial client will not accept blocks unless it has received the checkpoint This generates a base of stake for the POS system. A year should be enough time so that no one person has a large portion of the stake. Thanks, so they can't get rid of that "trusted/centralization" part right? Also your ISP maybe playing con tricks on you and you never get the right checkpoints, with Bitcoin you simply verify if your most recent blocks took millions to produce by checking if the hash is right(you need to have a rough idea of the height of the chain as well), and if you only ever going to spend several thousand USDs, most likely nobody will try to attack you this way. |
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Would it be beyond reason or scope for developers of bitcoin to implement a hybrid proof of stake / PoW system? Is it too late to do this? This gives much more security to the chain as it requires both 51% of all coins AND 51% of network hash to be owned by one person or pool.
Interesting solution. Apparently discussed before, for example, here. While I have strong faith in Bitcoin and in general in the community, this issue does concern me, especially with the way mining is going. I'm just thinking there has to be a solution, hopefully without requiring a hard fork. I haven't really taken time to look into PoS, but it sounds extraordinarily stupid to me: if I were a botnet operator who insert millions of nodes into the network to broadcast my fake PoS blockchain, which can be easily made because there is no requirement on the amount of work, how do you know which chain is real? Also what if several people controlling large stakes are kidnapped and forced into give their private keys? |
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Miners don't have the incentive to undermine peoples' trust in Bitcoin.
Well... not until JPMorgan Chase decides to provide the incentive for a large pool operator to attack Bitcoin....  Miners can find out easily and will complain loudly, "I found a block, but my node doesn't even see it on the network! Something fishy must be going on with the pool!" |
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Anyway it's a relief to know that only 45% of that 40% belows to Bitfury itself, so without the cooperation of other miners they are not a threat.
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For a country known for making shit that isn't worth anything, they sure are having a field day with BTCs.
Not field day really, but field test. We can bullshit all day here because people like DPR and Chinese exchanges are out there to take the blunt of state violence, so we can be sure that the whole thing is safe for our everyday, much less bold and reckless uses. |
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Of course ghash.io would do something about it. Like any mining pool would want to bring down the network, their source of massive income ........
Still we couldn't just count on the good will of the mega pool like we did every time in the past(Deepbit, BTC Guild...), it's intriguing why miners keep flocking to the biggest pool and whether something could be done about it. Do we know how much hash power is from CEX.io mining contracts (which go through ghash.io) vs independent miners? I would love to know the answer to this as well.... Yup, if Ghash.io really wants to help the network, it would be a good first step to publish such data.... |
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You can't fight something new and creative with something backward.
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Of course ghash.io would do something about it. Like any mining pool would want to bring down the network, their source of massive income ........
Still we couldn't just count on the good will of the mega pool like we did every time in the past(Deepbit, BTC Guild...), it's intriguing why miners keep flocking to the biggest pool and whether something could be done about it. |
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Hey I wasn't suggesting violent revolution  . Wouldn't be a bad thing if more Chinese citizens were more open about how corrupt and just plain ignorant their leaders are however. No government that uses mafia techniques to pressure CEOs to crush new technology should have the respect of tech-savvy citizens. I mean it is rather disappointing how childishly the PBOC and Chinese gov't are going about trying to "protect" their citizens from bitcoin. All this secret strong-arming of secondary companies that provide services related to bitcoin and all this simplistic propaganda to "justify" what they are doing. There is very little reference even to their own laws in this garbage. It sounds more like something from North Korea than a modern state that leads finance and technology. Not that I much prefer the Federal Reserve or the ECB and all the Western Governments and their "cold war" against bitcoin hehe. It's just pretty embarrassing to see Chinese gov't and corporations always in the news with crazy declarations that sound like something from some Banana Republic. Not to mention the endless fraud scandals of US-listed Chinese companies. Look at Bobby Lee scrambling to jump through hoops and think up some convoluted system to continue letting people trade while he grovels at the feet of the officials, repeating endlessly how he doesn't intend to challenge the gov't and he wants to cooperate. Meanwhile the officials are swatting down everything he thinks up like a game of Whack-A-Mole Plus the general issues of the internet censorship and blockage, like they have blocked the Guardian UK website recently (nobody even knows why) and the thing about the ban on game consoles and censorship of all sorts of media. Personally I am sick of the oligarchy we have in the West and I hope Bitcoin can help combat the central and private bank monopolies but there is no reason that Chinese shouldn't be furious about the "paternal" treatment they receive from their own gov't. It certainly will be interesting to see what happens in the next few months when all these deadlines for banning things and stopping transactions pass in China. Obviously I have nothing against you personally, I agree with just about everything you say in your post and I hope more and more people in China start to think in the way you suggest. Asia sure can help bring more power to the people, what with all those people they have... BTW, you bought under $10?  Jeeez, I am jealous of that my friend  Yeah, I was pretty much in this because all other means of "subversion" have failed disastrously, nothing was fit for the job of taking down a poweful enough oligarchy, the CCP managed to crush everything, including Twitter, the rock star of the "Arab Spring", it was about time something like Bitcoin to make its premiere to the world, however you look at it. I used to support U.S hegemony because I failed to see a better way out(Chinese/Russian obviously not an alternative), turned out that I am no Satoshi Nakamoto I am confident that we are not bound to be left behind, oppressive terrains are even more suitable for Bitcoin to grow, that's what it's for. There are still all kinds of methods to try, I think Bobby is probably just a bit unimaginative, cryptographically. |
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I am not sure you understand my point. I was just pointing out that China is largely irrelevant at this point. Despite it's large GDP, in the end it is just another primitive 3rd-world dictatorship and it will remain so as long as its citizens tolerate being ruled over by a tiny, corrupt, unelected elite. China's bitcoin economy is being crushed by these ignorant, megalomaniacal, hereditary leaders and it will be left in the dust by countries which have at least some facade of democracy which stops "fearless leaders" from handing down holy pronouncements to CEOs to ban everything they don't understand . Yeah, let's give up peaceful regime change with monetary revolution and pick up guns and fight the hell out of it. Money talks everywhere, people will see their interest and flock to where it's best protected(i.e., the free market), isn't that the whole point of Bitcoin? As for selling bitcoin below 2000 Chinese monopoly money. Well THANK GOD I wasn't born in China so I have the freedom to buy and sell however much I want whenever I want. That said, I bought all my bitcoin below US$100 and I have NOT sold a single tiny fraction of it. If the ignorant Chinese gamblers who are so terrified of their glorious party leaders didn't start freaking out every time they hear a rumor then the price never would have gotten down to 2000 CNY.
Last time I checked, I can still buy with bank transfer, just like any U.S/European citizen, and I do not need to submit copies of my ID/residence proof, just my ID card number, period. I bought all my coins when they were below $10, good times, when wires to Gox took only a day or two. Anyway, good luck to the serious bitcoin investors and users in China, they are going to need it. The unfortunate fact is that there is no rule of law or financial freedom in China and people unlucky enough to be prisoners in that dystopia can't just ignore their infallible masters.
No rule of law means greater financial freedom sometimes , when it comes down to money, no one who can accumulate much in the system is a fool and genuinely believes the Ponzi scheme can last forever, soon the CCP apparatchiks could not just ignore Bitcoin, and nothing, but blockchain is infallible in this world. Not that it's going to have an effect on bitcoin in the longterm, it will just hurt China and its people....
No longterm effect for sure, it will hurt no one but those practice backward-thinking. |
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Well, probably only poor suckers like you will get scared the hell out of you by some crazy ass dictators anyway, like those who sold me their coins at CNY 2000. Meanwhile huobi continues to be the largest exchange in terms of volume. If you believe their stats - wasn't it reported they were completely rigged? That's OKCoin, as for Huobi, I actually tried to measure it by conducting a series of trades at different times, all of my orders went through, according to the bids/asks listed on the page at the moment, and I can always withdraw what I have in my account, based on the speed at which the orders are filled, I would say it's indeed plausible that Huobi has the volume it claims. But maybe it's just me and I should really register a few more accounts for the test, I encourage you to try yourself as well. They won't mess with real accounts. They would just invent fake accounts and increase volume that way. If you put it that way, then I would say to a small time trader like me, for a zero trading-fee exchange like Huobi there is really no difference between coins changing hands between puppet accounts controlled by site opreators or controlled by some big whales(or maybe even me if I can be bothered to put together a bot), while the volume created by the later is usually considered somehow "real", I could totally understand it if you still consider it rigged though. |
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Well, probably only poor suckers like you will get scared the hell out of you by some crazy ass dictators anyway, like those who sold me their coins at CNY 2000. Meanwhile huobi continues to be the largest exchange in terms of volume. If you believe their stats - wasn't it reported they were completely rigged? That's OKCoin, as for Huobi, I actually tried to measure it by conducting a series of trades at different times, all of my orders went through, according to the bids/asks listed on the page at the moment, and I can always withdraw what I have in my account, based on the speed at which the orders are filled, I would say it's indeed plausible that Huobi has the volume it claims. But maybe it's just me and I should really register a few more accounts for the test, I encourage you to try yourself as well. |
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I believe the FBI would sell its BTC at a discount. All goods sell below their their market value at government auctions.
Usually, but not always, and those who didn't follow the rules paid dearly for it: http://en.wikipedia.org/wiki/Brown%27s_bottom |
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