Author: David Vorick 2015-11-10 20:37:21
Published on: 2015-11-10T20:37:21+00:00
One potential solution to reducing the orphan rate and increasing transaction throughput without increasing miner centralization pressure is the use of weak blocks as a form of pre-consensus. Weak blocks are blocks that meet a target with a lower difficulty, typically 5%, and can be circulated among miners to reduce block propagation times and orphan rates. However, this scheme does not address the adversarial case where large, difficult-to-verify blocks can still drive up the orphan rate for smaller miners. A new construction has been proposed that introduces a set of consensus rules to protect small miners even from the adversarial case. After a block is found, pre-consensus for the next block begins by building a chain of weak blocks which meet a target that has 5% the difficulty of a full block. Each weak block can introduce at most 200kb of new transactions to the chain, and when the next strong block is found, it must be at the head of a weak block chain and it must itself introduce a maximum of 200kb in new transactions. The maximum size of a strong block is 16mb, but can be composed of any number of weak blocks.On average, weak blocks will be found every 30 seconds and each block will build on top of 20 weak blocks, resulting in an average block size of 4mb. Creating larger blocks requires building on top of weak blocks, incentivizing miners to build on the most recent weak block and decreasing the likelihood of adversarial mining. The construction also achieves better censorship resistance as actively trying to censor certain transactions requires ignoring all weak-block chains that contain the offensive transaction, resulting in consistently producing smaller blocks. However, larger miners may have an incentive to withhold weak blocks to drive smaller miners off the network. To combat this behavior, miners can be directly rewarded for announcing weak blocks. The orphan rate for weak blocks may also be higher for smaller miners due to the increased rate of appearance, but this is unlikely to create issues since small miners can still have high visibility of the longest weak-block chain. Overall, the forced-weak-blocks scheme provides a potential solution to increasing transaction throughput while reducing the orphan rate and miner centralization pressure. However, additional analysis is needed to ensure that there are no new attack vectors or mal-aligned incentives introduced.
Updated on: 2023-06-11T01:01:48.623841+00:00