Not Everyone Wants to Fix Bitcoin’s ‘Time Warp Attack’ – Here’s Why
Bitcoin's open-source developers do not agree with many things, but they can be forgiven if they think one of them is best known as an "attack".
Still, there is a split in the conversations surrounding Bitcoin's long "Time Warp Attack" – there is a good reason. First, Mark Friedenbach, co-founder of Blockstream, recently discovered that when developers embrace and implement ideas, they can help with bit coin expansion, that is, reach more users and process more transactions faster. I did.
But since the announcement of last week, this discovery has changed the conversation about the attack. In other words, the miner is meant to explain how to submit a block containing a larger timestamp than is necessary to solve the difficulty of creating a new block .
As a result, prominent thinkers in the bitcoin development community are divided into issues that have been discussed since 2012.
For example, Greg Maxwell, co-founder of Block Stream and one of Bitco's most famous developers, recently asked for a solution to the long-time bit-corking attack on the bitcoin mailing list. Maxwell has been particularly silent about Friedenbach's proposal. However, the call occurred after the chat about this research, which was formally called "forward blocks", began.
As a result, this partitioning is likely to continue.
Eventually, Friedenbach's work suggests that developers who want to protect the protocol are tempted. If you increase the block size of Bitcoin, you can ask everyone who upgrades the software without upgrading. (Some people who see that these trivial parameters have long been at the heart of the controversy between communities, think of it as "innovation.")
Nonetheless, according to a new study by Friedenbach, modifications to the attack have become much more challenging.
But to get started, it helps to understand why the attack starts.
Individual actors (miners) on the network report the time when an event occurs when a transaction occurs or a block is created. So there is a small opportunity for someone to manipulate a little bit of time. Even following the bit code rule that the network node constantly checks.
Miners therefore sometimes report blocks with the wrong time. It's easy to see because there is a timestamp in front of the block, one block at a time (which looks basically out of sequence by default).
To see why this happened, Chainalysis, a block-chain analytics firm, recently wrote a report on how error rates have changed over time.
"Errors that decline over time in timestamps reflect people's evolution." Co-authored the article, Gladwell told CoinDesk that the mining industry appears to have "spiked" timestamp errors when viewing the technology. I insisted. shift.
For example, when miners joined to form a "pool" in early 2012, the percentage of timestamp errors increased to 8% of timestamps.
Gladwell suggests that this data is due to a mistake rather than a malicious cause, because the miner must get used to the new equipment.
Over time, an "attack" is a bit different in that miners who distort the rules to make money require more specific manipulations. This can happen when the miners collide with each other and report the wrong timestamps farther and mess up the speed at which they can mined the blocks.
Fortunately, this attack is difficult to execute.
Maxwell said, "I think of other people, and I have not given a big priority to fixing this vulnerability, because if you need a lot of hashes and someone else starts using it, you can easily stop it," Maxwell said.
If a group of miners collect most of the hash rate, the time attack is the worst bitcoin worry. (Chinalysis chief economist Philip Gladwell spoke to CoinDesk and said, "There will be other problems."
One is the centralization of the network. And the main reason that bitcoin should be set separately from other cryptocurrencies is that it is not controlled by one object. Needless to say, miners with power at this point can do what is known as "51 percent attack," which can then have an impact on the network.
However, even if it is difficult to implement, the developer considers this a problem. If you like, you can easily edit.
In his request for a proposal, Maxwell said he had an idea that he had tried BitCoin's test net a few years ago, but I want to make sure there are no other problems.
"We thought it would be useful to ask the list if we knew about the backwards compatible time warp fix proposals that others preferred before we decided early on to take action on a particular approach to solve the previous problem, I did .
"Backward compatibility" is the key. The requirement is that the change does not have a chance to partition the network.
At the request of Maxwell, several other suggestions came in.
Bitcoin core contributor Johnson Lau presented good ideas and bad ideas to show the tradeoffs of various approaches. He argued that "the innocent" way is to require the block not to submit time earlier than that block.
However, because it requires a certain type of change, you can divide BitCoin's software into two versions. Lau claims the trick is to find solutions that reduce the risk of timewarp attacks and reduce the risk of fragmentation.
"The goal is to find a small but sufficiently time-limited warp attack, as well as being large enough to avoid fragmentation," he added. He added that he thinks this can be achieved. In this "naive" version of this naive approach
Lau's idea even mentions philosophical discussion of "soft fork", a backwards compatible way to change bitcoin code, and how different types can lead to different results.
Bram Cohen, creator of BitTorrent, says, "Softforks are usually better when they are not orphaned in unmodified miners. Nowadays, we're focusing our efforts on decryption.
But he supported Lau's proposal, but he argued about the 3 hour time window. Cohen said, "I am having difficulty in accepting any attack, but three of every two weeks is not a big problem."
Other developers, Scott Roberts, said CoinDesk, in particular, has submitted suggestions for "bitcoin," not "off the mark." After all, Cohen agrees with Cohen though he thinks the three hours are "too tight".
"I do not know what the decision will be, but it's as simple as restricting the timestamp from three hours to 24 hours from the previous timestamp," Roberts said.
The problem, however, is that eradicating the Time Warp attack will ruin future blocks.
Fixing a time warp attack in the & # 39; impossible direction & # 39; can prevent time blocks from achieving on-chain scaling because it makes time warping impossible. Work proof It may be worth it to deploy for upgrade or to increase the censoring resistance of sharding. "Friedenbach added to CoinDesk:
"But the main advantage [of scaling bitcoin] that excites people will disappear."
Thinking about this, Friedenbach would preserve future blocks, but suggested another proposal to eliminate the "worst attack" of a time-varying attack. He argued that "it can be deployed early to prevent reckless exploitation of Time Warp bugs."
However, many bit coin engineers can not be sure that pure forward blocks are worth preserving.
Adam Back, CEO of Blockstream, thinks it's an interesting study, but he's not convinced the community will support it.
"While Mark considers it useful to explore a technical possibility, the main constraint is that there is a consensus on creating a great balance of decentralization, censorship-resistance and self-verification costs for indiscriminate first-tier scale," Coindex Said.
The forward block is interesting because it increases the capacity of the bit coin without hard fork. The type of change that can divide the bit coin into two is still powerful.
The reason why everyone was forced to make undesirable changes and reduce decentralization was the main reason the community fought so hard in Bitcoin's scaling debate over the years, Back said the community would not lightly consider this type of change did.
He even claimed to have a "simpler, less hacked approach" than Friedenbach to increase the layer 1 size of bit coin.
Friedenbach continues to argue that continuing blocks are still worth discussing, even as these types of criticism continue to roll, arguing that they are worth preserving with tools.
"The dangerous consequences of Time Warp bugs can be avoided without blocking the bug and blocking the future blocks or related scaling solutions."
Srikanta H. U (@ srikanta) clock picture of Unsplash
CoinDesk, a leader in block-chain news, is a media outlet that pursues the highest standards of journalism and adheres to strict editorial policies. CoinDesk is an independent operating subsidiary of the Digital Currency Group, which invests in cryptocurrencies and block-chain startups.
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