Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 86BBD2419 for ; Sat, 20 Jul 2019 11:07:23 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-40136.protonmail.ch (mail-40136.protonmail.ch [185.70.40.136]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 707A4E6 for ; Sat, 20 Jul 2019 11:07:22 +0000 (UTC) Date: Sat, 20 Jul 2019 11:07:14 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=default; t=1563620839; bh=1+Yb/6Hv0UCvwUQvzxyZLduvqLEfFLh2uCyK9imvI3o=; h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References: Feedback-ID:From; b=SBHLU/7Slfcii9RocFMWbxaFoa5EQLdfjPqwW0+t2Qp/zk8wruKM3MgwvAgZisES9 SjnFOSQdlF9lSnHrW23IH4EkOQhtNaxmZIU3FnFmV1Q6PNSnDF+PhgMBDNUa9mNIpX 6NotJjWToLo3eFZ+z9loluMAoNVa5UDZbhgg2MZk= To: "Kenshiro []" From: ZmnSCPxj Reply-To: ZmnSCPxj Message-ID: In-Reply-To: References: <207DBF48-E996-440D-ADDC-3AEC9238C034@voskuil.org>, , <-FVjDC_47DKPnkjAvcOAh3XMnIBIKspnLWrbpNlgE043OsEAJx9ZT5I3m7XWgwbsVps3QlwP7XSDu5yZ5JWSLxGiJM99T1ycjqqP7AUrtzo=@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 X-Spam-Status: No, score=-2.2 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, FROM_LOCAL_NOVOWEL, RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Sat, 20 Jul 2019 11:48:36 +0000 Cc: Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] Secure Proof Of Stake implementation on Bitcoin X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 20 Jul 2019 11:07:23 -0000 Good morning Kenshiro, > > >>>=C2=A0For example, if you are capable of disrupting a coin such that i= ts value is very likely to drop, you can buy short options as leverage. > Suppose you hold a large stake of coins and know you control a significan= t fraction, enough that a censorship attack by you will be so disruptive th= at the coin price will drop. > You take out a short contract with the contract price at the "hopium" lev= el others have (say 10% higher), buying enough options that you can cover t= he current price of your owned stake, plus some more options. > Suppose you buy, a number of options equal to twice your stake. > > Thank you for the explanation, I understand it now. But what percent of B= TC trades are short options? If everyone is doing short options, the attack= is very dangerous as you say, but if only a small percent of trades is don= e in short options, then it's not a big problem.=C2=A0 It is immaterial, because this is just *one* possible economic attack. Further leverage can always be had as Bitcoin does not exist in isolation. > > And this type of attack could also be done in PoW by evil miners. It's on= ly one step more, they have to purchase a lot of BTC before the attack, buy= many short options and execute the attack. Purchasing 50% of BTC is a prob= lem because of the price, but that's the same for PoW or PoS. Miners cannot feasibly take over 50% of energy sources in the world. > > >>>=C2=A0Let's suppose there are two big whales in your coin. > Each of them owns 50% of the total staked value. > Let's say "wait many blocks" parameter is 100 blocks. > > >>>One whale puts all his coin in a single UTXO. > The other has distributed his stake in 100,000 different UTXOs. > > I think there is a misunderstanding here, you forgot to divide the 50% st= aking weight of the evil whale by 100.000. No, you have a misunderstanding of your ***own*** system. You forgot that you indicated that a staking UTXO is banned from adding a n= ew block for "wait many blocks", as you indicated. Thus it is immaterial that each tiny stake of the evil whale is tiny: only = the tiny stakes of the evil whale are in play during the time that the sing= ular big UTXO by the honest whale is banned. Thus it has 100% of the stake during those 100 blocks. The honest whale gets 1 block (with very high probability) and then the evi= l whale gets the rest of the blocks for 100 blocks. ?Now again, consider that the situation indicates that there are in fact on= ly two actual stakers, each of whom have 50% of the staked funds, thus ther= e are no other stakers (even though the evil whale appears to be multiple s= eparate stakers) because 50% + 50% =3D 100%. I did indicate "each of them owns 50% of the total staked value", did I not= ? The rest of your counterargument ***completely forgets*** this, so I will i= gnore it. A whale composed of many tiny fishes is still a whale. It is immaterial that there may exist many small stakers who individually c= an overpower a tiny stake of the evil whale: the evil whale will still domi= nate during those times that the honest whale is banned because of your add= itional rule that "a staker who creates a block is banned from creating ano= ther block for many blocks": the evil whale simply dominates from having ma= ny tiny stakes, each of which can be banned with little effect on the actua= l power of the evil whale over the coin. > >>>=C2=A0We already know that miners are setting up mines at locations wh= ere energy is being wasted (e.g. oil well gas flares, putting up solar pane= ls instead of just letting sunshine pointlessly heat up their roofs, etc.),= and channeling the wasted energy into productive activity. > > I'm sure a big percent of mining will be done in this way, but if there i= s still dirty energy like nuclear energy or others is because we can't get = all the energy we need from clean sources (and that's excluding bitcoin min= ing). So even being very optimistic about bitcoin mining, it will steal cle= an energy sources from other human needs which will make us keep using dirt= y energy. So PoW makes use dirty energy sources in a direct or indirect way= . It is immaterial: what matters is the economics. Dirty energy is dirty because it causes damage to the economy by creating s= ickness and preventing people from surviving long lives and producing for t= he economy, destroys ecology and reduces biodiversity (and many products ar= e derived from the variety of lifeforms available) and so on. Thus, all energy uses will inevitably move towards cleaner energy sources a= s competition arises. > > >>>=C2=A0Thus, adding more rules is rarely the optimal thing to do. > > Proof of Stake is more complex than PoW, so you need to add a few more ru= les. Of course the rules must be well designed and tested, but as I explain= ed above there is no problem with the extra rule of giving a great increase= in staking weight to coins together in a single UTXO, because there is wai= t time for each staking deposit. You have demonstrated no such thing, merely demonstrated your own willful i= ncompetence in designing protocols. I will no longer respond. Regards, ZmnSCPxj