From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 93E25C002D for ; Tue, 18 Oct 2022 14:30:40 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 6CE86418D2 for ; Tue, 18 Oct 2022 14:30:40 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 6CE86418D2 Authentication-Results: smtp4.osuosl.org; dkim=pass (2048-bit key) header.d=blockstream-com.20210112.gappssmtp.com header.i=@blockstream-com.20210112.gappssmtp.com header.a=rsa-sha256 header.s=20210112 header.b=76joS51p X-Virus-Scanned: amavisd-new at osuosl.org X-Spam-Flag: NO X-Spam-Score: -1.899 X-Spam-Level: X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id U5mUoF98mdJ3 for ; Tue, 18 Oct 2022 14:30:39 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.8.0 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org EC6B341755 Received: from mail-pg1-x534.google.com (mail-pg1-x534.google.com [IPv6:2607:f8b0:4864:20::534]) by smtp4.osuosl.org (Postfix) with ESMTPS id EC6B341755 for ; Tue, 18 Oct 2022 14:30:38 +0000 (UTC) Received: by mail-pg1-x534.google.com with SMTP id 129so13460238pgc.5 for ; Tue, 18 Oct 2022 07:30:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=blockstream-com.20210112.gappssmtp.com; s=20210112; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :from:to:cc:subject:date:message-id:reply-to; bh=YoBR2gKcosBEBZSzXqKpZz6OK7N93avQPPcQWHFAGGA=; b=76joS51p6zpVH3aYbIz+BZl6TL7Q8KpbdD2+WmEkZfOwbXV5pGSM+WvyjUFJ479JxW DP5vf9443qPKu76Udfa4ZTMIaifag6f781RUC52huBiuzMn4AkUA7DgGFkuUxf7GPlSP 9RnK8fL+JRkRHWrco2wlZqQz0DNNWsNtucP0kfbNthVztQ50cxJs4Palp/D8S+m2HDXp Zr2zrWtaiFNJe1/RGe1On+RgK52OGa6eV4sa2t0HPbj/apExCEvZ4ayYGcKsVAjOwq14 m/1piNm2I2703xKr8s7T6MUPNe8WRsZEwbjC5vT119NCgF2Of7TErxOM7qNxoOHwBKoy yUYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=YoBR2gKcosBEBZSzXqKpZz6OK7N93avQPPcQWHFAGGA=; b=M3j00+CPstEFbTRRLG2sRikOXAUTBlHh2Squ0gmHOfIjy52aggCEq5jYpEhreh2xVn j/+8t1KiKQOuYS729tWfOLqaSOYotU7eJ5mI03Wi7millwzOUlibdASkTq2gznwIDvcv v1WjransMKtvGFJhFycMHbmEGhAQ3mWilYkNpERanMfp9P3mg1zM5D4VZu+SDhdX70on jF/Oo+vC/5TRSqLkO91pysQUWQWFYJEQL2NOm8HAQhgDkwHeDXIeXzIhy4oFLpdfLJcI z3WCyxh0b77+/SfnPwoy0YDMtR9OJMANXsvZ4/G5uXjTRShO3bq+Xh9MgEvZrlLxxE0k 1GPA== X-Gm-Message-State: ACrzQf34V4HjiWwe8aU/mOT9qHQ6SrtTd52+P0f0zd6iDOHfyAD78BJi Xk3SYYcCPzYTeQQGIdXny7rlEIVmUHj4GEqREnHd+Q== X-Google-Smtp-Source: AMsMyM4IpFrdUPqWwz6A198aKkbw+xukazrwzwGh+LYw0XQV1ElDp3qxHdMUyO1C1sNzzprgWk4LBm6xkmca96PDsa8= X-Received: by 2002:a63:1e56:0:b0:462:970:e0de with SMTP id p22-20020a631e56000000b004620970e0demr2978143pgm.90.1666103438291; Tue, 18 Oct 2022 07:30:38 -0700 (PDT) MIME-Version: 1.0 References: <903a46d95473714a7e11e33310fe9f56@yancy.lol> <2f4344b4c7952c3799f8766ae6b590bf@yancy.lol> In-Reply-To: From: "Russell O'Connor" Date: Tue, 18 Oct 2022 10:30:26 -0400 Message-ID: To: Jeremy Rubin , Bitcoin Protocol Discussion Content-Type: multipart/alternative; boundary="0000000000009954bc05eb4fef7b" Subject: Re: [bitcoin-dev] Does Bitcoin require or have an honest majority or a rational one? (re rbf) X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Oct 2022 14:30:40 -0000 --0000000000009954bc05eb4fef7b Content-Type: text/plain; charset="UTF-8" On Tue, Oct 18, 2022 at 9:07 AM Jeremy Rubin via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > > However, what *is* important about what Satoshi wrote is that it is sort > of the "social contract" of what Bitcoin is that we can all sort of > minimally agree to. This makes it clear, when we try to describe Bitcoin > with differing assumptions than in the whitepaper, what the changes are and > why we think the system might support those claims. But if we can't prove > the new description sound, such as showing tip mining to be rational in a > fully adversarial model, it doesn't mean Bitcoin doesn't work as promised, > since all that was promised originally is functioning under an honest > majority. Caveat Emptor! > I still think it is misguided to think that the "honest" (i.e. rule following) majority is to just be accepted as an axiom and if it is violated, well, then sorry. The rules need to be incentive compatible for the system to be functional. The honest majority is only considered an assumption because even if following the rules were clearly the 100% dominant strategy, this doesn't prove that the majority is honest, since mathematics cannot say what is happening in the real world at any given time. Still, we must have a reason to think that the majority would be honest, and that reasoning should come from an argument that the rule set is incentive compatible. The stability of mining, i.e. the incentives to mine on the most work chain, is actually a huge concern, especially in a future low subsidy environment. There is actually much fretting about this issue, and rightly so. We don't actually know that Bitcoin can function in a low subsidy environment because we have never tested it. Bitcoin could still end up a failure if that doesn't work out. My current understanding/guess is that with a "thick mempool" (that is lots of transactions without large gaps in fee rates between them) and/or miners rationally leaving behind transactions to encourage mining on their block (after all it is in a miner's own interest not to have their block orphaned), that mining will be stable. But I don't know this for sure, and we cannot know with certainty that we are going to have a "thick mempool" when it is needed. It is most certainly the case that one can construct situations where not mining on the tip is going to be the prefered strategy. But even if that happens on occasion, it's not like the protocol immediately collapses, because mining off the tip is indistinguishable from being a high latency miner who simply didn't receive the most work block in time. So it is more of a question of how rare does it need to be, and what can we do to reduce the chances of such situations arising (e.g. updating our mining policy to leave some transactions out based on current (and anticipated) mempool conditions, or (for a sufficiently capitalized miner) leave an explicit, ANYONECANSPEND transaction output as a tip for the next miner to build upon mined blocks.) --0000000000009954bc05eb4fef7b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Tue, Oct 18, 2022 at 9:07 AM Jeremy Rubin via bitcoin-dev <bitcoin-dev@lists.lin= uxfoundation.org> wrote:

However, what *is* importa= nt about what Satoshi wrote is that it is sort of the "social contract= " of what Bitcoin is that we can all sort of minimally agree to. This = makes it clear, when we try to describe Bitcoin with differing=C2=A0assumpt= ions than in the whitepaper, what the changes are and why we think the syst= em might support those claims. But if we can't prove the new descriptio= n sound, such as showing tip mining to be rational in a fully adversarial m= odel, it doesn't mean Bitcoin doesn't work as promised, since all t= hat was promised originally is functioning under an honest majority. Caveat= Emptor!
=

I still think it is misguided to think that the "h= onest" (i.e. rule following) majority is to just be accepted as an axi= om and if it is violated, well, then sorry.=C2=A0 The rules need to be ince= ntive compatible for the system to be functional.=C2=A0 The honest majority= is only considered an assumption because even if following the rules were = clearly the 100% dominant strategy, this doesn't prove that the majorit= y is honest, since mathematics cannot say what is happening in the real wor= ld at any given time.=C2=A0 Still, we must have a reason to think that the = majority would be honest, and that reasoning should come from an argument t= hat the rule set is incentive compatible.

The stab= ility of mining, i.e. the incentives to mine on the most work chain, is act= ually a huge concern, especially in a future low subsidy environment.=C2=A0= There is actually much fretting about this issue, and rightly so.=C2=A0 We= don't actually know that Bitcoin can function in a low subsidy environ= ment because we have never tested it.=C2=A0 Bitcoin could still end up a fa= ilure if that doesn't work out.=C2=A0 My current understanding/guess is= that with a "thick mempool" (that is lots of transactions withou= t large gaps in fee rates between them) and/or miners rationally leaving be= hind transactions to encourage mining on their block (after all it is in a = miner's own interest not to have their block orphaned), that mining wil= l be stable.=C2=A0 But I don't know this for sure, and we cannot know w= ith certainty that we are going to have a "thick mempool" when it= is needed.

It is most certainly the case that= one can construct situations where not mining on the tip is going to be th= e prefered strategy.=C2=A0 But even if that happens on occasion, it's n= ot like the protocol immediately collapses, because mining off the tip is i= ndistinguishable from being a high latency miner who simply didn't rece= ive the most work block in time.=C2=A0 So it is more of a question of how r= are does it need to be, and what can we do to reduce the chances of such si= tuations arising (e.g. updating our mining policy to leave some transaction= s out based on current (and anticipated) mempool conditions, or (for a suff= iciently capitalized miner) leave an explicit, ANYONECANSPEND transaction o= utput as a tip for the next miner to build upon mined blocks.)
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