There are "upgrades" in any system, and the same goes for blockchains. Upgrading software in a centralized system is very simple, you just need to click "Upgrade" in the app store. But in a decentralized system like the blockchain, “upgrading” is not that simple. Because there is no centralized organization, every code upgrade of digital assets such as Bitcoin requires the unanimous approval of the community. If the community cannot reach an agreement, the blockchain is likely to form a fork.
A hard fork is a software upgrade that does not support backward compatibility. Typically, these situations occur when a node adds new rules in a way that conflicts with the old node's rules. New nodes can only interact with software nodes running the new version. As a result, the blockchain split, producing two separate networks: one operating under the old rules and one operating under the new rules.
So now there are two networks running in parallel. They will continue to produce blocks and transactions, but will no longer work on the same blockchain. All nodes have the same blockchain (and the history still exists) until the blockchain network reaches the forked block, but after that they will have different blocks and transactions.
Since there is the same history, if you held coins before the fork, you will get coins on both networks at the same time. Suppose you had 5 BTC in hand when the fork occurred at block 600,000. You can choose to spend the 5 BTC on the original blockchain when the block height reaches 600,001, but this consumption at block height 600,001 will not be recorded on the newly generated blockchain. Assuming the encryption has not changed, these 5 tokens will still be present in your private key on the new forked network.
Another example of a hard fork is the one that occurred in 2017 when Bitcoin split into two separate chains, the original Bitcoin (BTC) and the new Bitcoin Cash (BCH). The fork came after a lot of debate in the community over the scaling of block size. Bitcoin Cash (BCH) proponents want to increase the block size, while Bitcoin (BTC) proponents oppose the change.
An increase in the block size requires a modification of the rules. This was done before the SegWit soft fork (more on that later), so nodes will only accept blocks smaller than 1MB. If you create a 2MB block, other nodes will refuse to validate.
Only nodes that have upgraded their software to support block sizes greater than 1MB will accept these blocks. Of course, this makes them incompatible with previous versions, so only nodes with the same protocol can communicate with each other.
A direct impact of the fork is that it may cause the user's deposit/withdrawal to be rolled back.
For example, a blockchain forked out a new chain. At this time, you transfer an account to the Cobo wallet. The transaction appears on the new chain, and you also check the transaction record on the block browser. , but then, the blockchain community reached a consensus and decided to give up the new chain and return to the old chain, then the transaction records generated on the new chain will also be invalid, causing your previous transaction operations to fail. This is "rollback" ".
In addition, forks may also lead to "replay attacks" on users' transactions.
Briefly explain the "replay attack": if a fork has a valid transaction, then the transaction may be "replayed" to another fork and confirmed again, that is, if you transfer money on a chain, you Coins on another chain may also be transferred.
Therefore, for the safety of funds, it is recommended that you pay attention to the official announcement at any time. If there is a fork, do not transfer money for the time being, and wait for the end of the fork before proceeding.
If you happen to perform a transfer operation during the fork and find that the coins are "missing", please don't worry, you can contact the exchange to retrieve your coins, if you are transferring from a local wallet, update the data of the local wallet , clear the cache.
