Published on: 2016-02-12T16:09:01+00:00
The context explores the idea of designing clients to warn users about soft forks and the potential safety advantages of doing so. While the reference client can provide warnings for high Proof-of-Work (POW) soft forks, many Simplified Payment Verification (SPV) clients cannot. To address this, it is suggested to implement a delay between version number changes and rule activation. This would allow nodes to receive a warning urging them to update their software.Furthermore, the context proposes specific guidelines for increasing difficulty intervals and updating targets at each difficulty re-targetting. The aim is to eventually reach a target of zero after 64 weeks, resulting in a difficulty level that is 256 times higher than the header. By implementing these guidelines, the hope is to enhance the security and stability of the network.Additionally, the context highlights an important point about the vulnerability of block withholding attacks. A proposal to fix this issue with a soft fork was presented, but it was noted that the technique does not align with the standard definition of a soft fork used by the Bitcoin development and research community. The proposed approach may be termed a "pseudo-soft-fork" and requires further analysis to determine its effectiveness compared to a simpler hard-fork implementation.To tackle block withholding attacks, another solution is put forth in the context. This solution involves redefining the block Proof-of-Work (PoW) target to be less than the difficulty, with the last two bytes representing the target. Miners are required to include a blinded hash of the target along with additional data in the coinbase of the blocks. Importantly, miners cannot switch targets arbitrarily and must submit all shares that meet the PoW criteria. Secondary verification is delegated to the miner, who must communicate proof of their target hash in a non-hashed area of the block.This proposed solution can be deployed as a soft fork with miner opt-in triggering across multiple difficulty cycles. Initially, the last bit of the block hash must be zero, followed by the last two bits in the next cycle. This progression continues over 16 difficulty cycles to minimize significant increases in block timings. By the end of this process, the nominal difficulty would have been reduced by a factor of 2^16 (65536), while the block target makes mining each block significantly harder.The context concludes by mentioning the possibility of progressing over more difficulty cycles through clever soft fork rules, such as Vitalik's "timewalking" attacks that allow for effective granular lowering of the nominal difficulty. Critiques are welcomed regarding these proposals, demonstrating an openness to further improvements and refinements in the Bitcoin network's security and performance.
Updated on: 2023-08-01T17:51:11.708328+00:00