Author: Rune Kjær Svendsen 2015-09-18 20:17:40
Published on: 2015-09-18T20:17:40+00:00
The issue of >50% attacks on Bitcoin is a real problem as Bitcoin cannot function if the majority of mining power is dishonest. There is no way around this as it is how proof-of-work functions and without it, we lose Bitcoin. The suggestion that UTXO set hashes replace block hashes or even that it should be in the block header is not made, rather it is suggested as an addition to the existing consensus rules. Full nodes can still verify the chain with the added step of hashing the UTXO set for every block, which can easily be deferred to after proof-of-work has been verified already so that no work is wasted unless a 51% attack is in effect. It is argued that this is a moot point since Bitcoin is useless anyway under such circumstances.It is not being suggested that miners discard the blockchain history. A miner has an incentive to be absolutely sure that the chain he’s building on is the right one. If he’s wrong, he loses money/income. There’s simply no reason for a professional miner not to do the full initial sync, which only needs to be done once. Non-miners who just want to check the balance of their wallet, however, really don’t need to retrieve information about Hal Finney sending bitcoins to Satoshi in 2010. In any case, this practice isn’t sustainable. In the end, it isn’t possible to control whether a miner verifies the entire blockchain anyway since anyone can send the UTXO set over the wire. Not letting the proof-of-work cover the UTXO hash doesn’t solve this problem; it only makes it impossible to know whether a given UTXO set is the one that the majority is mining without retrieving the entire blockchain and doing the verification yourself. People can choose to skip that regardless of what is done. Furthermore, all nodes have the option of deciding which level of security they want. This does not lessen the security of the protocol, rather it strengthens the security of something that is already possible to do (build on top of an unverified blockchain), but we’d rather want that people do not do.
Updated on: 2023-06-10T22:49:16.024888+00:00