[bitcoin-dev] Drivechain -- Request for Discussion

Dear list, I've been working on "drivechain", a sidechain enabling technology, for some time. * The technical info site is here: www.drivechain.info * The changes to Bitcoin are here: https://github.com/drivechain-project/bitcoin/tree/mainchainBMM * A Blank sidechain template is here: https://github.com/drivechain-project/bitcoin/tree/sidechainBMM As many of you know, I've been seeking feedback in person, at various conferences and meetups over the past year, most prominently Scaling Milan. And I intend to continue to seek feedback at Consensus2017 this week, so if you are in NYC please just walk up and start talking to me! But I also wanted to ask the list for feedback. Initially, I was hesitant because I try not to consume reviewers' scarce time until the author has put in a serious effort. However, I may have waiting too long, as today it is actually quite close to a working release. Scaling Implications --------------------- This upgrade would have significant scaling implications. Since it is the case that sidechains can be added by soft fork, and since each of these chains will have its own blockspace, this theoretically removes the blocksize limit from "the Bitcoin system" (if one includes sidechains as part of such a system). People who want a LargeBlock bitcoin can just move their BTC over to such a network [1], and their txns will have no longer have an impact on "Bitcoin Core". Thus, even though this upgrade does not actually increase "scalability" per se, it may in fact put an end to the scalability debate...forever. This work includes the relatively new concept of "Blind Merged Mining" [2] which I developed in January to allow SHA256^2 miners to merge-mine these "drivechains", even if these miners aren't running the actual sidechain software. The goal is to prevent sidechains from affecting the levelness of the mining "playing field". BMM is conceptually similar to ZooKeeV [3] which Peter Todd sketched out in mid-2013. BMM is not required for drivechain, but it would address some of the last remaining concerns. Total Transaction Fees in the Far Future ----------------------------------------- Some people feel that a maximum blocksize limit is needed to ensure that future total equilibrium transaction fees are non-negligible. I presented [4] on why I don't agree, 8 months ago. The reviewers I spoke to over the last year have stopped bringing this complaint up, but I am not sure everyone feels that way. Juxtaposition with a recent "Scaling Compromise" ------------------------------------------------- Recently, a scalability proposal began to circulate on social media. As far as I could tell, it goes something like "immediately activate SegWit, and then HF to double the nonwitness blockspace to 2MB within 12 months". But such a proposal is quite meager, compared to a "LargeBlock Drivechain". The drivechain is better on both fronts, as it would not require a hardfork, and could *almost immediately* add _any_ amount of extra blockspace (specifically, I might expect a BIP101-like LargeBlock chain that has an 8 MB maxblocksize, which doubles every two years). In other words, I don't know why anyone would support that proposal over mine. The only reasons would be either ignorance (ie, unfamiliarity with drivechain) or because there are still nagging unspoken complaints about drivechain which I apparently need to hear and address. Other Thoughts --------------- Unfortunately, anyone who worked on the "first generation" of sidechain technology (the skiplist) or the "second generation" (federated / Liquid), will find that this is very different. I will admit that I am very pessimistic about any conversation that involves scalability. It is often said that "talking politics lowers your IQ by 25 points". Bitcoin scalability conversations seem to drain 50 points. (Instead of conversing, I think people should quietly work on whatever they are passionate about until their problem either is solved, or it goes away for some other reason, or until we all agree to just stop talking about it.) Cheers, Paul [1] http://www.drivechain.info/faq/#can-sidechains-really-help-with-scaling [2] http://www.truthcoin.info/blog/blind-merged-mining/ [3] https://s3.amazonaws.com/peter.todd/bitcoin-wizards-13-10-17.log [4] https://www.youtube.com/watch?v=YErLEuOi3xU&list=PLw8-6ARlyVciNjgS_NFhAu-qt7HPf_dtg&index=4