Author: Sergio Demian Lerner 2015-08-10 22:11:10
Published on: 2015-08-10T22:11:10+00:00
On August 7, 2015, Sergio Demian Lerner via bitcoin-dev proposed a one-time hard fork to reduce the block rate to half, or an average of 5-minute blocks. While some argue that there are no drastic technical problems with this change, Pieter Wuille disagrees. He explains that all problems resulting from propagation delay are literally doubled by doing so. Although efficient propagation algorithms like the relay network make the ratio between propagation time and interblock time grow sublinearly with larger blocks, changing the interblock time affects it exactly proportionally. Lerner argues that this ratio may have improved 20x since miners began using the TheBlueMatt relay network, so deteriorating the ratio 2x does not put miners in an unknown future but in a future which is far better than the state they were in a year ago. Lerner also mentions that SPV mining has improved the ratio another 2x because headers can be pushed even faster and fit in a single network packet. With a better wire protocol, a 10 MB block could be propagated faster than the time it takes currently to propagate an empty block. Doubling the block size has a smaller effect on centralization pressure than reducing the interblock time. Lerner acknowledges that SPV mining is a bad centralization thing but believes it's impossible to avoid. He would like the relay network to be embedded into the standard network protocol, using local route optimizations to reduce latency for block propagation. Lerner also argues against the security assumption of SPV clients, stating that the incentive follows directly from the cheating cost (the subsidy). Even if miners do not know each other, they know that someone will not waste 25 BTC to cheat them for 25 BTC with a probability of 1/100. Lerner claims that SPV mining is safe as long as it is done for a certain bounded period of time and bounded number of blocks, and SPV mining incentive will stay until there is no subsidy. Lastly, Lerner notes that higher block rates mean lower variance, which is good for miners. Having a lower average block interval strengthens Bitcoin's value proposition, so miners would be delighted that their bitcoins are more worthy.
Updated on: 2023-06-10T18:51:48.329561+00:00