Chain splits and resolutions__ block chains

An often misunderstood topic was that of chain splits and how they are potentially. With the recent proposal from shaolinfry discussing User activated Soft forks (UASF) Getting much attention, the Se misunderstandings must is clarified to fully understand the implications of chain splits and their potential S. Types of forks

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Miners can create chain splits through the deliberate orphaning of blocks to is appear to valid. The Users maintain a set of consensus rules that they require to all blocks. When users disagree about the sets of consensus rules to enforce, they'll follow a different chain. To simplify discussion, we'll skip the case where the consensus rules are agreed upon, but miners, decide to orphan blocks For the other reasons, and cases where there are more than two sets of consensus rules. In the following examples, there are two sets of rules, the Red rules and the yellow rules. In these examples, the Red rules are original rules being enforced, and the yellow rules are the modified rules. Orange rules are the combination of both Red and yellow rules (both rule sets agree this these blocks are). Incompatible Hard fork

An incompatible are the simplest type of chain split to understand. At a certain blocks height, some users decide to implement a new ruleset. In this case, the new ruleset is completely independent of the original rules. Incompatible Hard Fork

A hard fork Occurs after some miners decide to mine on the new ruleset, and some in the old continue. No block produced under the new rules are valid under the old rules, and vice versa. The Ethereum/ethereum Classic Split is a example of this kind of split. In this case, the chains are eternally split with no chance of ever converging, no matter how much work are mined into each Chain. semi-compatible Hard Forks

A semi-compatible Hard fork occurs whenever the rulesets intersect, but there are some blocks that are valid in only one O f The chains for each chain. Semi-compatible Fork

In this cases, miners can prevent a chain split by mining only Orange rule blocks. However, once a miner mines a Red or yellow block, the chain splits. It is possible for the chains to converge if miners eventually put together a exclusively Orange chain starting from when The users accepted yellow rules that surpassed the total work of both of the other chains. If They ever did this, both the Red/orange and Yellow/orange chains is would by orphaned red/yellow, and clients D a single chain. There are no major forks of this type I am aware of. The best bet for miners in this case (depending on the specifics) would typically is to just mine Orange blocks, Preventin G any chain split. By doing so, miners are effectively turning a semi-compatible fork into a Soft. compatible Hard Fork

In a hard fork, the ruleset expands, to include all of the previous rules, but also and allowing other conditions. Hard Fork

When the rules expand, as soon as a miner mines a blocks with the yellow rules, the chain splits. This type of split would diverge as long as the yellow chain contains more work than the Orange chain. One danger in this type of the????? chain contains more work, the yellow chain would be orphaned. The Users of the yellow chain must not is sure that a vast majority of hashpower to be is on this chain initially, but Wil L continue to is on this chain for eternity. An example of this type of the fork is Bitcoin XT, Bitcoin Classic, and Bitcoin Unlimited. Soft Fork

A Soft Fork is when the ruleset are tightened and the yellow rules are completely covered by the Red rules (thus only Orang E and Red rulesets).

The chain split can occur whenever a miner creates a Red block. The users who use the Red ruleset would follow that chain, and the users who use the yellow ruleset'll follow the Orange chain. In this case, if the majority of hashpower ever starts enforcing the Orange rules, the Red chain would become orphaned. This type of fork occurred in Bitcoin's history numerous times with changes such as BIP66, CSV, CLTV, and are in the propos Ed Segwit Soft Fork. reorganization Risk and Split risks

Both massive reorganizations and chain splits present to users and dangers. A massive reorganization can cause previously accepted transactions to disappear, which'll guarantee that a large number Of people would lose money in the process. In this case, perhaps a year ago you were paid 10BTC for your car, and a year later, that transaction essentially DISAPPEA Rs from the ledger, and your chain are abandoned. You are have no car and no bitcoins. This type is behavior would cause a great loss of confidence in the currency. Depending on the type of split, a massive reorganization would only affect users of the looser ruleset. Users of the tighter ruleset would never get reorganized.

A chain split also presents risk. The value of Ethereum took a tumble after it split from Ethereum Classic. It adds confusion to the marketplace (which is really ethereum? The one with the original rules, or the "one with the" centralized Ethereum Foundation enforce today?). A chain split affects all users adversely. There are cases where a split may be preferred say two groups have vastly different interests and are best served Ng their own wants, rather than compromising). Mitigating Risk

Risk for most of this forks can is mitigated by both miners and users, in most cases.

For a incompatible hard fork, no mitigation plan can occur. The chain is splitting, so long as some miners and some users want it to. There is no that can happen. This is the equivalent of getting a divorce decree and parting ways, never to interact.

For a semi-compatible soft fork, miners have prevent both a chain fork and massive. If The majority of miners choose to mine only Orange blocks, users would remain on one chain and reorganizations'll be Li Mited to a small number of blocks.

For a compatible hard fork, risk are exclusively on the yellow rule users. Their best mitigation is to ensure the majority of the economy are on their side. It ' s also important to make sure the majority of the miners are also on their side, initially the otherwise Split. Without the majority of the economy, the value of the Orange blocks would be greater, thus pulling miners interested in pro Fit to their side, leading to a massive reorganization. Extreme care must is taken in this scenario (something that is not present with Bitcoin XT, Bitcoin Classic, nor the prop osed Bitcoin Unlimited). The former would activate with a mere 75% of hashpower, and Bitcoin Unlimited to has no threshold for activation.

For a soft fork, the risk are exclusively on the Red rule users. Their best mitigation strategy is to ensure this they have the economy on their side, and the vast majority of miners Owing the Red rules OR the vast majority of miners on the Orange rules. This may seem a bit counterintuitive, but if the vast majority of miners are mining the Orange rules, then they would remai N in consensus with the Orange users and won't get orphaned. Miners can mitigate this by only mining blocks in the Orange set and orphaning the Red set.

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Miners have a significant role into mitigating this risk. In every case except the incompatible Hard Fork, the miners can prevent a chain Fork. For the semi-compatible hard fork, they can doing this by converting it into a soft fork. For the compatible hard fork, they can only do this by rejecting the hard fork. For the soft fork case, they does this by enforcing the soft fork. However, even without the miners doing this, users have a incentive to protect themselves by enforcing the Orange rules a nd rejecting anything does not meet them. This means rejecting hard forks and enforcing soft. epilogue:escaping a Miner imposed ruleset change

Many, including Jeff Garzik, have cast suspicion upon soft forks because-they do not give users a choice. The nature of Bitcoin and other Proof of Work based Blockchains cannot prevent miners from enforcing stricter rules than u Sers agree to. However, users do have power-by invoking a incompatible hard. In this case, the users would force the chain to split by introducing a new ruleset (which may include a proof of work change, But does not require one). This ensures users always have is the escape from a miner imposed ruleset that they. This is way, if the economy and users truly reject a soft fork rule change, they always and have Aim the rules they wish. It may being inconvenient, but the same is true by any attack by the miners on users.

Original address: https://medium.com/@alpalpalp/chain-splits-and-resolutions-d3398bddf4ab