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 DF6D8C077D for ; Fri, 17 Jan 2020 13:55:01 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id C161820523 for ; Fri, 17 Jan 2020 13:55:01 +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 G+PLaZ1AzwUf for ; Fri, 17 Jan 2020 13:54:57 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-40132.protonmail.ch (mail-40132.protonmail.ch [185.70.40.132]) by silver.osuosl.org (Postfix) with ESMTPS id 142DB20198 for ; Fri, 17 Jan 2020 13:54:57 +0000 (UTC) Date: Fri, 17 Jan 2020 13:54:50 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=default; t=1579269294; bh=QY7NjJDD0GCsfU9anwUb7BhUq3kPb6Wgh2Pa5u4TZtk=; h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References: Feedback-ID:From; b=w9UD6xzAsZl0Sy05pgVS/Ek8Qmz/jQNijrWDEOD+sobwTAxupgAWU0mpSmhJ/8ake tosHNzIT56B/wG05uIi/EQqX+zDpDmzfUtucrMCCS3R6lztuB1zMS7Mt8GqN2m40hN 8EVKtej95KcIYpa6kP5LFCokLtGJUsHOSQ2JvT/o= To: Robin Linus , Bitcoin Protocol Discussion From: ZmnSCPxj Reply-To: ZmnSCPxj Message-ID: In-Reply-To: References: <0RSAH-PjblJV6Q7TGosFHAEdc9QGauCQ_knCzMwcoGdW4Qt49ts-egDkIwM-X_f0RjsPMquwdnmB6spunH379ICEAJQgUH7R1SE8CuZs7pI=@protonmail.com> <6JaReZbjL3U0QrirtiCdgk107cNmQHiLbbJIDctf8uGUiqJOLvZwRLLPUQXAjzfAqRQBpaqtytcKhq1hvtSDwwaKGthwy40SWHDRnTpBkJA=@protonmail.com> <6pcznun9_VnOIV7D28YeCiWqSLtPnN7syJvgGVp_VIo_DAZyp2mDYZQxg6IT5dJagroU-TKgUUjLrJm12TlbhLCzwjftY6_OhIB3ej6o44E=@protonmail.com> Feedback-ID: el4j0RWPRERue64lIQeq9Y2FP-mdB86tFqjmrJyEPR9VAtMovPEo9tvgA0CrTsSHJeeyPXqnoAu6DN-R04uJUg==:Ext:ProtonMail MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 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: Fri, 17 Jan 2020 13:55:02 -0000 Good morning Robin, > Hi Joachim,=C2=A0 > > > if anyone can halt operation of a sidechain with just tiny investment. > > It'll be impossible to halt a healthy chain with a tiny investment becaus= e halting a chain costs you at least as much as the side chain rewards. The= "invested time value per block" of all honest stakers converges against th= e block reward. If imbalanced, someone will stake more bitcoin to get the c= heap sidechain rewards. Exactly the same market mechanism secures PoW. > > For a decentralized consensus via resource consumption it doesn't matter = which limited resource you consume. The only relevant factor is that the va= lue of the block reward is sufficient to motivate people to invest a lot of= that resource. To motivate them to invest so much that an attacker cannot = invest more. Independently of the resource, the amount of honestly invested= resources converges against the value of the block reward. Also known as MC =3D MR. This is in fact the core of the argument *against* this kind of global micr= ochain system: each individual chain will either: * Pay ridiculously high fees per transaction, because the microchain has a = small number of transactions because that is the entire *point* of microcha= ins. * Pay insufficient fees per block, making it easy to attack, meaning the se= curity of the chain has to be centralized around a few actors anyway (e.g. = checkpoints, like what every altcoin implements), which is not much better = than the custodial case you are complaining against. In order to have a sidechain that is as secure as Bitcoin today, you need: * Sidechain fees to cover both *current Bitcoin fees* plus *current Bitcoin= block rewards*. Consequently, the sidechain has to have either *more* users than Bitcoin to= day, or *higher* fees than Bitcoin today. Unless of course you propose to have the sidechain issue its own coin, in w= hich case it is not much more than an altcoin. Still, the real-world value of the total block rewards for that altcoin wil= l have to match the real-world value of the total block rewards of Bitcoin = in order to have security even approaching Bitcoin. > > Thus, I would even go further with my claim and argue that the security o= f bitcoin-backed PoS is exactly as strong as PoW because in both cases thei= r security is proportionally to the dollar value of their block reward. PoS= sidechain security depends only on a sufficient userbase and thus, block r= eward value. Only if the consumed resource matches what is consumed under PoW. Otherwise it is not much better than a low-PoW altcoin, i.e. easily attacka= ble unless it centralizes around the developers. I understand the desire to smoothen the experience of onboarding new users = to Bitcoin. But this path is not much better than the custodial solutions you are tryin= g to avoid anyway. Regards, ZmnSCPxj