Rolling UTXO set hashes

Summary:

Peter Todd, a Bitcoin developer, has stated that previous UTXO commitment schemes do not require miners to participate in generating a commitment. He argues that these schemes do not require a soft-fork to deploy. However, all of the approaches still require a network-wide choice to be useful. A validating node that does not maintain a UTXO must get proof of its unspentness from somewhere for at least the block which contains a spend of the UTXO. In a world where such a model is deployed network-wide, that proof information is generated by the wallet and relayed wherever needed. However, in a partial deployment, nodes are required that can produce the proof for other nodes, and the ability to produce a proof is significantly more expensive than running either an old or new full node. This ability to produce proofs becomes harder when there are different models deployed at once with different criteria for which UTXOs need a proof. Pieter Todd believes that it is worthwhile to investigate solutions to the "how can we efficiently compare UTXO sets" problem separately from the "how do we reduce full node costs by sending proofs instead of it maintaining the data". Rolling UTXO set hashes are a solution for just the first issue and one that has very low costs and no normative data structures at all. However, he cautions that before reducing the responsibilities of full nodes, there will need to be implementations, experiments, and analysis.

Updated on: 2023-05-20T02:20:28.454847+00:00