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The Verge Hack, Explained
- twog 8y agoPoW coins outside Bitcoin will never work. This will continue to happen over & over again to every smaller PoW chain
- ribosometronome 8y agoWhat issues has Ethereum run into as PoW? I've only heard about contract vulnerabilities.
- EGreg 8y agoPoW is leader based consensus. It’s slow and can’t handle millions of simultaneous payments. Why do new distributed ledger technologies still prefer to use it, when there are other, far faster consensus algorithms out there?
- jayd16 8y agoProbably because they're not trying to actually solve a problem. They're just on the hype train. More seriously, if the name of the game is efficiency then a distributed ledger isn't the answer.
- blattimwind 8y ago> More seriously, if the name of the game is efficiency then a distributed ledger isn't the answer. And if you're only looking for immutability, then time-stamping is already good enough (and available since the late 90s or so). I suppose you can use a Merkle tree and then proceed to put "Blockchain" in your marketing materials without technically lying.
- pitaj 8y agoBCH at 32 MB blocks can handle 108 Tx/s. It would only need to grow to 6 GB blocks to handle the 20k Tx/s that VISA claims they can handle. It would only need to grow to 600 MB blocks to handle the 2k Tx/s that VISA handles on average. 600MB every 10 minutes is no sweat for even modest internet connections nowadays. With technology like weak blocks and the lighting network and other side-chains the network can handle it no problem.
- XR0CSWV3h3kZWg 8y agoThis is pretty offtopic, but the amount of time it takes to download the block isn't the only factor, amount of time to process & verify the block is pretty important as well as the storage costs etc. That's all pretty moot at the moment as BCH is averaging ~50kb blocks.
- onion-soup 8y agoWhat is Nano?
- kang 8y agoThis statement is against the spirit of HN. Although I agree that none of other pow coins currently have as robust code, but making an absolute statement like that is not rational. You are saying every merge in the core code protocol is trusted by you even if that code has not even been written yet.
- thisisit 8y agoWell on point, PoW dint work on Bitcoin as well. The only reason it dint become a problem was that Bitcoin wasn't famous at that time. From Digital Gold by Nathaniel Popper: Laszlo’s CPU had been winning, at most, one block of 50 Bitcoins each day, of the approximately 140 blocks that were released daily. Once Laszlo got his GPU card hooked in he began winning one or two blocks an hour, and occasionally more. On May 17 he won twenty-eight blocks; these wins gave him fourteen hundred new coins that day. Satoshi knew someone would eventually spot this opportunity as Bitcoin became more successful and was not surprised when Laszlo e-mailed him about his project. But in responding to Laszlo, Satoshi was clearly torn. If one person was taking all the coins, there would be less of an incentive for new people to join in. “I don’t mean to sound like a socialist,” Satoshi wrote back. “I don’t care if wealth is concentrated, but for now, we get more growth by giving that money to 100% of the people than giving it to 20%.” As a result, Satoshi asked Laszlo to go easy with the “high powered hashing,” the term coined to refer to the process of plugging an input into a hash function and seeing what it spit out. But Satoshi also recognized that having more computing power on the network made the network stronger as long as the people with the power, like Laszlo, wanted to see Bitcoin succeed.” One can imagine the outrage it will cause if it happened today.
- woah 8y agoThese kinds of shenanigans have been happening a lot on a small PoW chain called Amoveo. It’s been interesting to follow it since the founder is very honest and forthcoming about its difficulties, in contrast to most other blockchains.
- EGreg 8y agoThis is because, in decentralized networks that obstinately refuse to grant any special authority to third parties, accurately enforcing time synchronization is no simple matter. That depends on what you’re going for. The concept of time is actually a local phenomenon, as relativity shows. To compare whether events A and B happened first, you must first trace some path from A and B to a third party C (maybe C = A or B if you really want) and then ask C which came first. We had to deal with this when building our DLT. See this: https://intercoin.org/technology.pdf https://intercoin.org/technology.pdf
- danbruc 8y agoRelativistic effects are irrelevant at the level of precision required for running a system distributed across the surface of Earth, what you are describing is just due to a lack of properly synchronized clocks. Place an atomic clock at each node and there is no need for any C deciding the ordering of A and B. Alternatively you may also be able to use logical clocks like a Lamport clock or a vector clock to establish an ordering in a distributed system in absence of properly synchronized clocks but that depends on the use case.
- EGreg 8y agoNo. Relativity is actually a special case if this general principle. For a large and complex network, events A and B which are very far apart cannot be compared in any canonical way. The larger the network the less they can be compared. However, A can come before B relative to some reference point C. That’s enough to achieve most things. The point is that you shouldn’t have a global and continuous sense of time in distributed systems. Leslie Lamport has developed many things including vector clock over the years to address this. Our PTN is just the latest in a long line of examples. When you say that you have “no need” for C once you have synchronized clocks, not only are you ignoring relativity but you are also ignoring the byzantine generals problem. If Han Solo can benefit from claiming he shot first, why would I trust his clock? If you’re implementing a video game or cryptocurrency in a byzantine resilient way, how exactly would you have a continuous global sense of time? Go ahead the floor is yours.
- nextstep 8y ago>>>In both cases, this hack presents a strong argument for tending towards sticking to things proven to work and to be wary of overcomplicating things and thereby introducing unnecessary risks when people’s financial assets are involved. Which, I suppose, means two points for team Bitcoin. What? The same bitcoin that is betting everything on an untested and incredibly complex second-layer protocol called "lightning network" instead of just scaling with larger blocks?
- lawn 8y agoIt's indeed delusional to claim that Bitcoin developers have peoples' financial assets in mind when they celebrate fees of $50 and produce nothing else than "wait for second layer solutions they will magically solve everything".
- osteele 8y ago> instead of just scaling with larger blocks Blocks will need to be ~5TB to match Visa transaction volume. Some lightning network advocates are concerned about the effect that a size increase necessary to support even a fraction of this volume would have on mining centralization. Other concerns are listed here https://en.bitcoin.it/wiki/Block_size_limit_controversy https://en.bitcoin.it/wiki/Block_size_limit_controversy and here https://en.bitcoin.it/wiki/Scalability_FAQ#General_Block_Size_Increase_Theory https://en.bitcoin.it/wiki/Scalability_FAQ#General_Block_Siz...
- lawn 8y ago
- bronson 8y ago"Reality, however, often has a way of stubbornly refusing to conform to the axioms of free market economics." Great article.
- deleted 8y ago[deleted]
- danielvf 8y ago"Exactly how the largest protocol-level hack of a cryptocurrency in recent memory could preceed said cryptocurrency increasing in price and then announcing a partnership with the most trafficked porn-site on the internet is a question I’m forced to leave open-ended; my personal pet-theory is that it has something to do with the fact that the world makes no sense and human beings are all completely out of their goddamn minds."
- TheDong 8y agoPlease don't quote portions of the article with no added commentary or insight. We're all capable of reading and recognizing well-written portions of the posted content.
- sean2 8y agoThis was a particularly interesting bit though and I was hoping some people might explain/comment more about it. It seems that getting your crypto-currency hacked gives publicity and boosts value! See also: the Experian hack.
- SlowRobotAhead 8y agoClearly any plans with pornhub.com would have been made prehack. As to the value of the cryptocommodity (I refuse to call them currencies)... it’s like the author said.
- democracy 8y agoPlease do, I personally often read the comment section only, and something tells me I am not alone in this...
- is_true 8y ago+1
- kang 8y agoOne can always invent blockchain buzzwords like "Dark Gravity Wave" but even copying code requires understanding of algorithms.
- keyle 8y agoI snorted when I first heard the term. An old co-worker used to call 'universal differential', for weeks. Yeah that was IF statement.
- tromp 8y agoThis hack results from a basic design error: for difficulty adjustment to work properly, the window of recent blocks it considers must be relatively immune to time stamp manipulation. In other words, the allowed timestamp drift must be much smaller than the adjustment time window. Bitcoin allows a 2 hour drift, but has an adjustment window of 2 weeks. In verge's case, both are identical, at 2 hours. This is an open invitation to difficulty adjustment abuse.
- gtrubetskoy 8y ago> In verge's case, both are identical, at 2 hours. Naive question - is verge adjustment window defined in block time (as opposed to "human" time)? because > Bitcoin allows a 2 hour drift, but has an adjustment window of 2 weeks. The adjustment window is technically 2016 blocks, which is about two weeks in human time, but can in theory vary greatly if mining capacity fluctuates.
- tromp 8y agoI went looking through the source code and found that the adjustment window is indeed defined in block time as PastBlocksMax = 12 while nProofOfWorkTargetSpacing = 150 (half a minute for each of 5 different pow algorithms), giving an expected adjustment window of 12 * 150 = 1800 seconds. Apparently, the adjustment window, which needs to be way longer than the allowed timestamp drift, is in fact way shorter...
- tetha 8y agoAt that point, I got a bit scared, too. This feels way too much against the rule of thumb that code consuming untrusted input should never be able to modify or control it's own configuration or binaries (or, more generally, trusted input). In this case, the attacker can hijack 50% - 100% of the configuration of the weighting algorithm. For bitcoin, you can control around 4% at most without risking immediate attention. Unless mining speed increases by a factor of 40 or 50 suddenly.
- ikeboy 8y agoVitalik has laid out a method for doing the same thing in Bitcoin. See https://www.reddit.com/r/btc/comments/428tjl/softforking_the_block_time_to_2_min_my_primarily/ https://www.reddit.com/r/btc/comments/428tjl/softforking_the...
- sarreph 8y agoIs it possible to add (Cryptocurrency) after ‘The Verge’ in the title please? I thought it referred to the news outlet.
- deleted 8y ago[deleted]
- jameskegel 8y agoI was not aware that The Verge was still moving forward after Joshua Topolsky left, and their show "On The Verge" was cancelled.
- gepeto42 8y agoNot sure who said it first, but cryptocurrency truly is the Internet-wide bug bounty.
- w0mbat 8y agoThe gate metaphors in the article are so messed up they distracted me from the actual story. >> Gates Only Work When They’re Raised Well normally gates swing open and shut, maybe you mean some kind of portcullis, like in a castle? You have to raise those to open them. >> a gate that’s far too strong to break >> through and too high to climb over — >> this hack gets past it by finding a way >> to lower it so close to the ground that >> it can be stepped over So now gates rise out of the ground? I don't think the author has seen an actual gate.
- evancox100 8y agoLol I'm with you on this, I struggled too
- tadah 8y agoYou're holding it wrong. Think: https://en.m.wikipedia.org/wiki/Floodgate https://en.m.wikipedia.org/wiki/Floodgate
- dzgoldman 8y ago#gategate
- rando444 8y agoI'm very curious about the price increase. The only thing that comes to mind how something like that would be possible is if the news trends generated by this were somehow driving algorithmic trading .. either that or people investing in something they're just hearing of for the first time.. But even these possibilities don't seem rational. It just doesn't seem to make much sense... unless the whole thing was being driven and pushed by some larger unknown actor with a lot of resources .. (state government, goldman sachs, etc.)
- SlowRobotAhead 8y agoBut what lunatic reads of the hack - then invests!?
- sangnoir 8y agoI'm guessing an algorithmic one, which invests based on "buzz" and/or price trends leading to positive feedback cycles.
- sterlind 8y agoThis hack underscores the need for formal modeling systems like TLA+ or Coq. Essentially, you define successor state axioms, where: 1. start with a seed state. 2. non-deterministically choose the next step (e.g. submit a tx) 3. ask the system to prove the inverse of an invariant you want to check (e.g. hash power cannot fall below X% of total network power.) Decentralized protocols have bugs; trust only what you can prove.
- keyle 8y agoSo basically this time warp hack is allowing eval() on the chain history... What could go wrong?
- 49bc 8y ago> Indeed, major cryptocurrencies like Bitcoin and Ethereum have maintained their security quite well — better, arguably, than any other digital asset/payment system in history Am I missing something? And here I thought having to hard fork your currency goes in the “not very secure” bin.
- SlowRobotAhead 8y agoCan someone who touts the “but it’s decentralized!!” aspects of these systems- please to explain to me how an algorithm that adjusts mining difficulty is not a centralized and possibly destructive feature in control of a handful of people?