From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id D17E3C077D for ; Mon, 13 Jan 2020 02:03:07 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id BA94420111 for ; Mon, 13 Jan 2020 02:03:07 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id MrOeXg5IIztI for ; Mon, 13 Jan 2020 02:03:03 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-40130.protonmail.ch (mail-40130.protonmail.ch [185.70.40.130]) by silver.osuosl.org (Postfix) with ESMTPS id 8C3EF20023 for ; Mon, 13 Jan 2020 02:03:03 +0000 (UTC) Date: Mon, 13 Jan 2020 02:02:53 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=default; t=1578880981; bh=eGR9DGTC+lZ+tIauODtFSN32iIHoSQFwKzuzrNc+aD4=; h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References: Feedback-ID:From; b=Q3JPLrnPGmMUytEezMVfoPpNazgOZOu33fognBtL/8itoz2mJKbsraswiJstl+Jk0 OBCF8Pj2DbIQnoUXm1aF3zm80J8Ue8jNCBmwkRZsRBsZS2HYLza9o7GApbByKa5muJ wZFF/7bLYbDczsZ0s0Tuut5+GEfUJJQuYOMpYl5Y= To: ZmnSCPxj From: Robin Linus Reply-To: Robin Linus Message-ID: <2mw_wd_ocLESpSG9ST3yJBsJriHf1l5LsdQ2jLamTUUKTMmwUpcjEeohClnMHJl4qjXNW9mHQJiK65jmDHfLG3-nVSRse9PdXnXokGZ2_ac=@protonmail.com> In-Reply-To: References: Feedback-ID: 6FfHo99INKExF0tkDkemTyDa-LNBAaNSuYGo9F4rOzppmymRaL_liHzoQTtSnq1Ib2NLN4047Io_xKQzk5eD1w==:Ext:ProtonMail MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Mailman-Approved-At: Mon, 13 Jan 2020 03:25:24 +0000 Cc: Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] Coins: A trustless sidechain protocol 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: Mon, 13 Jan 2020 02:03:08 -0000 Good morning ZmnSCPxj, Thank you for your detailed feedback! Two topics: ## Lightning vs Sidechains Why an either-or-solution, if we can connect sidechains via the LN to get t= he best of both worlds? The LN works exceptionally great under the following conditions: - you're always online - you have BTC to manage your channels' inbound-capacity - you can afford BTC transactions =09- in your channel is much more than the minimum on-chain TX fees The next Billion users do not fit that category. They are on unreliable cel= l phone connections and do not have any BTC yet. And the more popular Bitcoin becomes, the fewer people can afford LN channe= ls. Even Eltoo requires your funds to be significantly higher than Bitcoin'= s TX fees, right? Already today, more and more services like tippin.me, BlueWallet, etc, prov= ide custodial solutions. For small amounts, custody is an acceptable workaround. And I love their us= ability. Install it and immediately I can send you $0.01. Yet, scaling thei= r approach globally does not lead to desirable outcomes, since we'd be back= to trusting banks with their Excel sheets. So let's make their internal ledgers public and trustless, via independent = sidechains. Decentralized Blockchains do scale decently up to a couple Mill= ion UTXOs. So a couple thousand Sidechains is probably sufficient for a glo= bal medium of exchange. Cross-chain communication without requiring cross-c= hain validation is possible via atomic swaps and through Bitcoin's LN. That= scales because it separates chain-validators from swap-validators. Bitcoin's LN acts as the central settlement layer for efficient cross-chain= transactions between all sidechains. So Endusers "living" in sidechains instead of directly in the LN has many a= dvantages: - no bitcoin blockspace required for on-boarding new users - no need to lock funds to provide inbound-capacity - no need to stay online or pay watch towers - no need to store channel histories - account balances can be much smaller than BTC TX fees Those are the exact same reasons why BlueWallet built their LndHub. But sid= echains can be trustless. Also a generic protocol provides flexibility for = sidechain innovations with arbitrary digital assets and consensus rules. ## Collateral Contract Thanks for mentioning that! I like the simplicity of your variant! It's bet= ter than my workarounds. I'll add it to the paper. However, in the long ter= m, the cleanest solution is to destroy the funds. Giving it to miners assum= es Alice does not control much Hash power, which is harder to reason about. Regards, robin =E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90 Original Me= ssage =E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90=E2=80=90 On Monday, January 13, 2020 1:21 AM, ZmnSCPxj wro= te: > Good morning Robin, > > The reason why I stopped considering sidechains for scaling and have sinc= e moved to Lightning Network development was that, on reflection, I realize= d sidechains still do not scale, even with stakes anchored on the mainchain= . > The issue is that sidechains, like any blockchain, still require that eve= ryone interested in it to propagate all their transaction to everyone else = interested in it. > Contrast this with Lightning Network, where you select only a tiny handfu= l of nodes to inform about your payment, even if you have a gigantic Lightn= ing Network. > > Or, more blithely: Let me get this straight, you already know blockchains= cannot scale, so your scaling proposal involves making more blockchains? > > You might point to the use of large numbers of sidechains with limited us= erbase, and the use of cross-chain atomic swaps to convert between sidecoin= s. > I would then point out that Lightning Network channel are cryptocurrency = systems with two users (with significantly better security than a 2-user si= dechain would have), and that Lightning Network payment routing is just the= use of cross-channel atomic swaps to convert between channelcoins. > Indeed, with a multiparticipant offchain updateable cryptocurrency system= mechanism, like Decker-Wattenhofer or Decker-Russell-Osuntokun ("eltoo"), = you could entirely replace sidechains with a mechanism that does not give c= ustody to your funds to anyone else, since you can always insist on using n= -of-n signing with you included in the signer set to prevent state changes = that do not have your approval. > > > > Regards, > ZmnSCPxj