<oembed><type>rich</type><version>1.0</version><author_name>npub1xqcwcttsyk0a64d63crrwsxp88pa42np37rw87hrfn4uku78g2aqltcnns</author_name><author_url>https://nostr.ae/npub1xqcwcttsyk0a64d63crrwsxp88pa42np37rw87hrfn4uku78g2aqltcnns</author_url><provider_name>njump</provider_name><provider_url>https://nostr.ae</provider_url><html>📅 Original date posted:2021-05-24&#xA;📝 Original message:Is this &lt;https://en.bitcoin.it/wiki/Proof_of_burn&gt; the kind of proof of&#xA;burn you&#39;re talking about?&#xA;&#xA;&gt;   if i have a choice between two chains, one longer and one shorter, i&#xA;can only choose one... deterministically&#xA;&#xA;What prevents you from attempting to mine block 553 on both chains?&#xA;&#xA;&gt; miners have a very strong, long-term, investment in the stability of the&#xA;chain.&#xA;&#xA;Yes, but the same can be said of any coin, even ones that do have the&#xA;nothing at stake problem. This isn&#39;t sufficient tho because the chain is a&#xA;common good, and the tragedy of the commons holds for it.&#xA;&#xA;&gt; you burn them to be used at a future particular block height&#xA;&#xA;This sounds exploitable. It seems like an attacker could simply focus all&#xA;their burns on a particular set of 6 blocks to double spend, minimizing&#xA;their cost of attack.&#xA;&#xA;&gt; i can imagine scenarios where large stakeholders can collude to punish&#xA;smaller stakeholders simply to drive them out of business, for example&#xA;&#xA;Are you talking about a 51% attack? This is possible in any decentralized&#xA;cryptocurrency.&#xA;&#xA;&#xA;On Mon, May 24, 2021 at 11:49 AM Erik Aronesty &lt;erik at q32.com&gt; wrote:&#xA;&#xA;&gt; &gt; &gt; your burn investment is always &#34;at stake&#34;, any redaction can result in&#xA;&gt; a loss-of-burn, because burns can be tied, precisely, to block-heights&#xA;&gt; &gt; I&#39;m fuzzy on how proof of burn works.&#xA;&gt;&#xA;&gt; when you burn coins, you burn them to be used at a future particular&#xA;&gt; block height: so if i&#39;m burning for block 553, i can only use them to&#xA;&gt; mine block 553.   if i have a choice between two chains, one longer&#xA;&gt; and one shorter, i can only choose one... deterministically, for that&#xA;&gt; burn: the chain with the height 553.   if we fix the &#34;lead time&#34; for&#xA;&gt; burned coins to be weeks or even months in advance, miners have a very&#xA;&gt; strong, long-term, investment in the stability of the chain.&#xA;&gt;&#xA;&gt; therefore there is no &#34;nothing at stake&#34; problem.   it&#39;s&#xA;&gt; deterministic, so miners have no choice.  they can *only* choose the&#xA;&gt; transactions that go into the block.  they cannot choose which chain&#xA;&gt; to mine, and it&#39;s time-locked, so rollbacks and instability always&#xA;&gt; hurt miners the most.&#xA;&gt;&#xA;&gt; the &#34;punishment&#34; systems of PoS are &#34;weird at best&#34;, certainly&#xA;&gt; unproven.   i can imagine scenarios where large stakeholders can&#xA;&gt; collude to punish smaller stakeholders simply to drive them out of&#xA;&gt; business, for example.   and then you have to put checks in place to&#xA;&gt; prevent that, and more checks for those prevention system...&#xA;&gt;&#xA;&gt; in PoB, there is no complexity.  simpler systems like this are&#xA;&gt; typically more secure.&#xA;&gt;&#xA;&gt; PoB also solves problems caused by &#34;energy dependence&#34;, which could&#xA;&gt; lead to state monopolies on mining (like the new Bitcoin Mining&#xA;&gt; Council).   these consortiums, if state sanctioned, could become a&#xA;&gt; source of censorship, for example.   Since PoB doesn&#39;t require you to&#xA;&gt; have a live, well-connected node, it&#39;s harder to censor &amp; harder to&#xA;&gt; trace.&#xA;&gt;&#xA;&gt; Eliminating this weakness seems to be in the best interests of&#xA;&gt; existing stakeholders&#xA;&gt;&#xA;&gt;&#xA;&gt;&#xA;&gt;&#xA;&gt; On Mon, May 24, 2021 at 4:44 PM Billy Tetrud &lt;billy.tetrud at gmail.com&gt;&#xA;&gt; wrote:&#xA;&gt; &gt;&#xA;&gt; &gt; &gt;  proof of burn clearly solves this, since nothing is held online&#xA;&gt; &gt;&#xA;&gt; &gt; Well.. the coins to be burned need to be online when they&#39;re burned. But&#xA;&gt; yes, only a small fraction of the total coins need to be online.&#xA;&gt; &gt;&#xA;&gt; &gt; &gt; your burn investment is always &#34;at stake&#34;, any redaction can result in&#xA;&gt; a loss-of-burn, because burns can be tied, precisely, to block-heights&#xA;&gt; &gt;&#xA;&gt; &gt; So you&#39;re saying that if say someone tries to mine a block on a shorter&#xA;&gt; chain, that requires them to send a transaction burning their coins, and&#xA;&gt; that transaction could also be spent on the longest chain, which means&#xA;&gt; their coins are burned even if the chain they tried to mine on doesn&#39;t win?&#xA;&gt; I&#39;m fuzzy on how proof of burn works.&#xA;&gt; &gt;&#xA;&gt; &gt; &gt; proof of burn can be more secure than proof-of-stake&#xA;&gt; &gt;&#xA;&gt; &gt; FYI, proof of stake can be done without the &#34;nothing at stake&#34; problem.&#xA;&gt; You can simply punish people who mint on shorter chains (by rewarding&#xA;&gt; people who publish proofs of this happening on the main chain). In&#xA;&gt; quorum-based PoS, you can punish people in the quorum that propose or sign&#xA;&gt; multiple blocks for the same height. The &#34;nothing at stake&#34; problem is a&#xA;&gt; solved problem at this point for PoS.&#xA;&gt; &gt;&#xA;&gt; &gt;&#xA;&gt; &gt;&#xA;&gt; &gt; On Mon, May 24, 2021 at 3:47 AM Erik Aronesty &lt;erik at q32.com&gt; wrote:&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt; I don&#39;t see a way to get around the conflicting requirement that the&#xA;&gt; keys for large amounts of coins should be kept offline but those are&#xA;&gt; exactly the coins we need online to make the scheme secure.&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; proof of burn clearly solves this, since nothing is held online&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;  how does proof of burn solve the &#34;nothing at stake&#34; problem in your&#xA;&gt; view?&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; definition of nothing at stake: in the event of a fork, whether the&#xA;&gt; &gt;&gt; fork is accidental or a malicious, the optimal strategy for any miner&#xA;&gt; &gt;&gt; is to mine on every chain, so that the miner gets their reward no&#xA;&gt; &gt;&gt; matter which fork wins.   indeed in proof-of-stake, the proofs are&#xA;&gt; &gt;&gt; published on the very chains mines, so the incentive is magnified.&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; in proof-of-burn, your burn investment is always &#34;at stake&#34;, any&#xA;&gt; &gt;&gt; redaction can result in a loss-of-burn, because burns can be tied,&#xA;&gt; &gt;&gt; precisely, to block-heights&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; as a result, miners no longer have an incentive to mine all chains&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; in this way proof of burn can be more secure than proof-of-stake, and&#xA;&gt; &gt;&gt; even more secure than proof of work&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; On Sun, May 23, 2021 at 3:52 AM Lloyd Fournier via bitcoin-dev&#xA;&gt; &gt;&gt; &lt;bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; Hi Billy,&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; I was going to write a post which started by dismissing many of the&#xA;&gt; weak arguments that are made against PoS made in this thread and elsewhere.&#xA;&gt; &gt;&gt; &gt; Although I don&#39;t agree with all your points you have done a decent&#xA;&gt; job here so I&#39;ll focus on the second part: why I think Proof-of-Stake is&#xA;&gt; inappropriate for a Bitcoin-like system.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; Proof of stake is not fit for purpose for a global settlement layer&#xA;&gt; in a pure digital asset (i.e. &#34;digital gold&#34;) which is what Bitcoin is&#xA;&gt; trying to be.&#xA;&gt; &gt;&gt; &gt; PoS necessarily gives responsibilities to the holders of coins that&#xA;&gt; they do not want and cannot handle.&#xA;&gt; &gt;&gt; &gt; In Bitcoin, large unsophisticated coin holders can put their coins in&#xA;&gt; cold storage without a second thought given to the health of the underlying&#xA;&gt; ledger.&#xA;&gt; &gt;&gt; &gt; As much as hardcore Bitcoiners try to convince them to run their own&#xA;&gt; node, most don&#39;t, and that&#39;s perfectly acceptable.&#xA;&gt; &gt;&gt; &gt; At no point do their personal decisions affect the underlying&#xA;&gt; consensus -- it only affects their personal security assurance (not that of&#xA;&gt; the system itself).&#xA;&gt; &gt;&gt; &gt; In PoS systems this clean separation of responsibilities does not&#xA;&gt; exist.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; I think that the more rigorously studied PoS protocols will work fine&#xA;&gt; within the security claims made in their papers.&#xA;&gt; &gt;&gt; &gt; People who believe that these protocols are destined for catastrophic&#xA;&gt; consensus failure are certainly in for a surprise.&#xA;&gt; &gt;&gt; &gt; But the devil is in the detail.&#xA;&gt; &gt;&gt; &gt; Let&#39;s look at what the implications of using the leading proof of&#xA;&gt; stake protocols would have on Bitcoin:&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; ### Proof of SquareSpace (Cardano, Polkdadot)&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; Cardano is a UTXO based PoS coin based on Ouroboros Praos[3] with an&#xA;&gt; inbuilt on-chain delegation system[5].&#xA;&gt; &gt;&gt; &gt; In these protocols, coin holders who do not want to run their node&#xA;&gt; with their hot keys in it delegate it to a &#34;Stake Pool&#34;.&#xA;&gt; &gt;&gt; &gt; I call the resulting system Proof-of-SquareSpace since most will&#xA;&gt; choose a pool by looking around for one with a nice website and offering&#xA;&gt; the largest share of the block reward.&#xA;&gt; &gt;&gt; &gt; On the surface this might sound no different than someone with an&#xA;&gt; mining rig shopping around for a good mining pool but there are crucial&#xA;&gt; differences:&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; 1. The person making the decision is forced into it just because they&#xA;&gt; own the currency -- someone with a mining rig has purchased it with the&#xA;&gt; intent to make profit by participating in consensus.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; 2. When you join a mining pool your systems are very much still&#xA;&gt; online. You are just partaking in a pool to reduce your profit variance.&#xA;&gt; You still see every block that you help create and *you never help create a&#xA;&gt; block without seeing it first*.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; 3. If by SquareSpace sybil attack you gain a dishonest majority and&#xA;&gt; start censoring transactions how are the users meant to redelegate their&#xA;&gt; stake to honest pools?&#xA;&gt; &gt;&gt; &gt; I guess they can just send a transaction delegating to another&#xA;&gt; pool...oh wait I guess that might be censored too! This seems really really&#xA;&gt; bad.&#xA;&gt; &gt;&gt; &gt; In Bitcoin, miners can just join a different pool at a whim. There is&#xA;&gt; nothing the attacker can do to stop them. A temporary dishonest majority&#xA;&gt; heals relatively well.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; There is another severe disadvantage to this on-chain delegation&#xA;&gt; system: every UTXO must indicate which staking account this UTXO belongs to&#xA;&gt; so the appropriate share of block rewards can be transferred there.&#xA;&gt; &gt;&gt; &gt; Being able to associate every UTXO to an account ruins one of the&#xA;&gt; main privacy advantages of the UTXO model.&#xA;&gt; &gt;&gt; &gt; It also grows the size of the blockchain significantly.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; ### &#34;Pure&#34; proof of stake (Algorand)&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; Algorand&#39;s[4] approach is to only allow online stake to participate&#xA;&gt; in the protocol.&#xA;&gt; &gt;&gt; &gt; Theoretically, This means that keys holding funds have to be online&#xA;&gt; in order for them to author blocks when they are chosen.&#xA;&gt; &gt;&gt; &gt; Of course in reality no one wants to keep their coin holding keys&#xA;&gt; online so in Alogorand you can authorize a set of &#34;participation keys&#34;[1]&#xA;&gt; that will be used to create blocks on your coin holding key&#39;s behalf.&#xA;&gt; &gt;&gt; &gt; Hopefully you&#39;ve spotted the problem.&#xA;&gt; &gt;&gt; &gt; You can send your participation keys to any malicious party with a&#xA;&gt; nice website (see random example [2]) offering you a good return.&#xA;&gt; &gt;&gt; &gt; Damn it&#39;s still Proof-of-SquareSpace!&#xA;&gt; &gt;&gt; &gt; The minor advantage is that at least the participation keys expire&#xA;&gt; after a certain amount of time so eventually the SquareSpace attacker will&#xA;&gt; lose their hold on consensus.&#xA;&gt; &gt;&gt; &gt; Importantly there is also less junk on the blockchain because the&#xA;&gt; participation keys are delegated off-chain and so are not making as much of&#xA;&gt; a mess.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; ### Conclusion&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; I don&#39;t see a way to get around the conflicting requirement that the&#xA;&gt; keys for large amounts of coins should be kept offline but those are&#xA;&gt; exactly the coins we need online to make the scheme secure.&#xA;&gt; &gt;&gt; &gt; If we allow delegation then we open up a new social attack surface&#xA;&gt; and it degenerates to Proof-of-SquareSpace.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; For a &#34;digital gold&#34; like system like Bitcoin we optimize for&#xA;&gt; simplicity and desperately want to avoid extraneous responsibilities for&#xA;&gt; the holder of the coin.&#xA;&gt; &gt;&gt; &gt; After all, gold is an inert element on the periodic table that&#xA;&gt; doesn&#39;t confer responsibilities on the holder to maintain the quality of&#xA;&gt; all the other bars of gold out there.&#xA;&gt; &gt;&gt; &gt; Bitcoin feels like this too and in many ways is more inert and&#xA;&gt; beautifully boring than gold.&#xA;&gt; &gt;&gt; &gt; For Bitcoin to succeed I think we need to keep it that way and&#xA;&gt; Proof-of-Stake makes everything a bit too exciting.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; I suppose in the end the market will decide what is real digital gold&#xA;&gt; and whether these bad technical trade offs are worth being able to say it&#xA;&gt; uses less electricity. It goes without saying that making bad technical&#xA;&gt; decisions to appease the current political climate is an anathema to&#xA;&gt; Bitcoin.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; Would be interested to know if you or others think differently on&#xA;&gt; these points.&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; [1]:&#xA;&gt; https://developer.algorand.org/docs/run-a-node/participate/generate_keys/&#xA;&gt; &gt;&gt; &gt; [2]: https://staking.staked.us/algorand-staking&#xA;&gt; &gt;&gt; &gt; [3]: https://eprint.iacr.org/2017/573.pdf&#xA;&gt; &gt;&gt; &gt; [4]:&#xA;&gt; https://algorandcom.cdn.prismic.io/algorandcom%2Fece77f38-75b3-44de-bc7f-805f0e53a8d9_theoretical.pdf&#xA;&gt; &gt;&gt; &gt; [5]:&#xA;&gt; https://hydra.iohk.io/build/790053/download/1/delegation_design_spec.pdf&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; Cheers,&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; LL&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; On Fri, 21 May 2021 at 19:21, Billy Tetrud via bitcoin-dev &lt;&#xA;&gt; bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; I think there is a lot of misinformation and bias against Proof of&#xA;&gt; Stake. Yes there have been lots of shady coins that use insecure PoS&#xA;&gt; mechanisms. Yes there have been massive issues with distribution of PoS&#xA;&gt; coins (of course there have also been massive issues with PoW coins as&#xA;&gt; well). However, I want to remind everyone that there is a difference&#xA;&gt; between &#34;proved to be impossible&#34; and &#34;have not achieved recognized success&#xA;&gt; yet&#34;. Most of the arguments levied against PoS are out of date or rely on&#xA;&gt; unproven assumptions or extrapolation from the analysis of a particular PoS&#xA;&gt; system. I certainly don&#39;t think we should experiment with bitcoin by&#xA;&gt; switching to PoS, but from my research, it seems very likely that there is&#xA;&gt; a proof of stake consensus protocol we could build that has substantially&#xA;&gt; higher security (cost / capital required to execute an attack) while at the&#xA;&gt; same time costing far less resources (which do translate to fees on the&#xA;&gt; network) *without* compromising any of the critical security properties&#xA;&gt; bitcoin relies on. I think the critical piece of this is the disagreements&#xA;&gt; around hardcoded checkpoints, which is a critical piece solving attacks&#xA;&gt; that could be levied on a PoS chain, and how that does (or doesn&#39;t) affect&#xA;&gt; the security model.&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; @Eric Your proof of stake fallacy seems to be saying that PoS is&#xA;&gt; worse when a 51% attack happens. While I agree, I think that line of&#xA;&gt; thinking omits important facts:&#xA;&gt; &gt;&gt; &gt;&gt; * The capital required to 51% attack a PoS chain can be made&#xA;&gt; substantially greater than on a PoS chain.&#xA;&gt; &gt;&gt; &gt;&gt; * The capital the attacker stands to lose can be substantially&#xA;&gt; greater as well if the attack is successful.&#xA;&gt; &gt;&gt; &gt;&gt; * The effectiveness of paying miners to raise the honest fraction of&#xA;&gt; miners above 50% may be quite bad.&#xA;&gt; &gt;&gt; &gt;&gt; * Allowing a 51% attack is already unacceptable. It should be&#xA;&gt; considered whether what happens in the case of a 51% may not be&#xA;&gt; significantly different. The currency would likely be critically damaged in&#xA;&gt; a 51% attack regardless of consensus mechanism.&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; &gt; Proof-of-stake tends towards oligopolistic control&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; People repeat this often, but the facts support this. There is no&#xA;&gt; centralization pressure in any proof of stake mechanism that I&#39;m aware of.&#xA;&gt; IE if you have 10 times as much coin that you use to mint blocks, you&#xA;&gt; should expect to earn 10x as much minting revenue - not more than 10x. By&#xA;&gt; contrast, proof of work does in fact have clear centralization pressure -&#xA;&gt; this is not disputed. Our goal in relation to that is to ensure that the&#xA;&gt; centralization pressure remains insignifiant. Proof of work also clearly&#xA;&gt; has a lot more barriers to entry than any proof of stake system does. Both&#xA;&gt; of these mean the tendency towards oligopolistic control is worse for PoW.&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; &gt; Energy usage, in-and-of-itself, is nothing to be ashamed of!!&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; I certainly agree. Bitcoin&#39;s energy usage at the moment is I think&#xA;&gt; quite warranted. However, the question is: can we do substantially better.&#xA;&gt; I think if we can, we probably should... eventually.&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; &gt; Proof of Stake is only resilient to ⅓ of the network demonstrating&#xA;&gt; a Byzantine Fault, whilst Proof of Work is resilient up to the ½ threshold&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; I see no mention of this in the pos.pdf you linked to. I&#39;m not aware&#xA;&gt; of any proof that all PoS systems have a failure threshold of 1/3. I know&#xA;&gt; that staking systems like Casper do in fact have that 1/3 requirement.&#xA;&gt; However there are PoS designs that should exceed that up to nearly 50% as&#xA;&gt; far as I&#39;m aware. Proof of work is not in fact resilient up to the 1/2&#xA;&gt; threshold in the way you would think. IE, if 100% of miners are currently&#xA;&gt; honest and have a collective 100 exahashes/s hashpower, an attacker does&#xA;&gt; not need to obtain 100 exahashes/s, but actually only needs to accumulate&#xA;&gt; 50 exahashes/s. This is because as the attacker accumulates hashpower, it&#xA;&gt; drives honest miners out of the market as the difficulty increases to&#xA;&gt; beyond what is economically sustainable. Also, its been shown that the best&#xA;&gt; proof of work can do is require an attacker to obtain 33% of the hashpower&#xA;&gt; because of the selfish mining attack discussed in depth in this paper:&#xA;&gt; https://arxiv.org/abs/1311.0243. Together, both of these things reduce&#xA;&gt; PoW&#39;s security by a factor of about 83% (1 - 50%*33%).&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;  &gt; Proof of Stake requires other trade-offs which are incompatible&#xA;&gt; with Bitcoin&#39;s objective (to be a trustless digital cash) — specifically&#xA;&gt; the famous &#34;security vs. liveness&#34; guarantee&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; Do you have a good source that talks about why you think proof of&#xA;&gt; stake cannot be used for a trustless digital cash?&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; &gt; You cannot gain tokens without someone choosing to give up those&#xA;&gt; coins - a form of permission.&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; This is not a practical constraint. Just like in mining, some nodes&#xA;&gt; may reject you, but there will likely be more that will accept you, some&#xA;&gt; sellers may reject you, but most would accept your money as payment for&#xA;&gt; bitcoins. I don&#39;t think requiring the &#34;permission&#34; of one of millions of&#xA;&gt; people in the market can be reasonably considered a &#34;permissioned currency&#34;.&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; &gt; 2. Proof of stake must have a trusted means of timestamping to&#xA;&gt; regulate overproduction of blocks&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; Both PoW and PoS could mine/mint blocks twice as fast if everyone&#xA;&gt; agreed to double their clock speeds. Both systems rely on an honest&#xA;&gt; majority sticking to standard time.&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; On Wed, May 19, 2021 at 5:32 AM Michael Dubrovsky via bitcoin-dev &lt;&#xA;&gt; bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt; Ah sorry, I didn&#39;t realize this was, in fact, a different thread! :)&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt; On Wed, May 19, 2021 at 10:07 AM Michael Dubrovsky &lt;mike at powx.org&gt;&#xA;&gt; wrote:&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt; Folks, I suggest we keep the discussion to PoW, oPoW, and the BIP&#xA;&gt; itself. PoS, VDFs, and so on are interesting but I guess there are other&#xA;&gt; threads going on these topics already where they would be relevant.&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt; Also, it&#39;s important to distinguish between oPoW and these other&#xA;&gt; &#34;alternatives&#34; to Hashcash. oPoW is a true Proof of Work that doesn&#39;t alter&#xA;&gt; the core game theory or security assumptions of Hashcash and actually&#xA;&gt; contains SHA (can be SHA3, SHA256, etc hash is interchangeable).&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt; Cheers,&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt; Mike&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt; On Tue, May 18, 2021 at 4:55 PM Erik Aronesty via bitcoin-dev &lt;&#xA;&gt; bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; 1. i never suggested vdf&#39;s to replace pow.&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; 2. my suggestion was specifically *in the context of* a working&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; proof-of-burn protocol&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; - vdfs used only for timing (not block height)&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; - blind-burned coins of a specific age used to replace proof of&#xA;&gt; work&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; - the required &#34;work&#34; per block would simply be a competition to&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; acquire rewards, and so miners would have to burn coins, well in&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; advance, and hope that their burned coins got rewarded in some far&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; future&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; - the point of burned coins is to mimic, in every meaningful way,&#xA;&gt; the&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; value gained from proof of work... without some of the security&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; drawbacks&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; - the miner risks losing all of his burned coins (like all miners&#xA;&gt; risk&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; losing their work in each block)&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; - new burns can&#39;t be used&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; - old burns age out (like ASICs do)&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; - other requirements on burns might be needed to properly mirror&#xA;&gt; the&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; properties of PoW and the incentives Bitcoin uses to mine&#xA;&gt; honestly.&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; 3. i do believe it is *possible* that a &#34;burned coin + vdf system&#34;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; might be more secure in the long run, and that if the entire space&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; agreed that such an endeavor was worthwhile, a test net could be&#xA;&gt; spun&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; up, and a hard-fork could be initiated.&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; 4. i would never suggest such a thing unless i believed it was&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; possible that consensus was possible.  so no, this is not an &#34;alt&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; coin&#34;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; On Tue, May 18, 2021 at 10:02 AM Zac Greenwood &lt;zachgrw at gmail.com&gt;&#xA;&gt; wrote:&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt; Hi ZmnSCPxj,&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt; Please note that I am not suggesting VDFs as a means to save&#xA;&gt; energy, but solely as a means to make the time between blocks more constant.&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt; Zac&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt; On Tue, 18 May 2021 at 12:42, ZmnSCPxj &lt;ZmnSCPxj at protonmail.com&gt;&#xA;&gt; wrote:&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; Good morning Zac,&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; &gt; VDFs might enable more constant block times, for instance by&#xA;&gt; having a two-step PoW:&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; &gt; 1. Use a VDF that takes say 9 minutes to resolve (VDF being&#xA;&gt; subject to difficulty adjustments similar to the as-is). As per the&#xA;&gt; property of VDFs, miners are able show proof of work.&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; &gt; 2. Use current PoW mechanism with lower difficulty so&#xA;&gt; finding a block takes 1 minute on average, again subject to as-is&#xA;&gt; difficulty adjustments.&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; &gt; As a result, variation in block times will be greatly&#xA;&gt; reduced.&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; As I understand it, another weakness of VDFs is that they are&#xA;&gt; not inherently progress-free (their sequential nature prevents that; they&#xA;&gt; are inherently progress-requiring).&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; Thus, a miner which focuses on improving the amount of energy&#xA;&gt; that it can pump into the VDF circuitry (by overclocking and freezing the&#xA;&gt; circuitry), could potentially get into a winner-takes-all situation,&#xA;&gt; possibly leading to even *worse* competition and even *more* energy&#xA;&gt; consumption.&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; After all, if you can start mining 0.1s faster than the&#xA;&gt; competition, that is a 0.1s advantage where *only you* can mine *in the&#xA;&gt; entire world*.&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; Regards,&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; &gt;&gt; ZmnSCPxj&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; _______________________________________________&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; bitcoin-dev mailing list&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; bitcoin-dev at lists.linuxfoundation.org&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&gt; https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt; --&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt; Michael Dubrovsky&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt; Founder; PoWx&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&gt; www.PoWx.org&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt;&gt; --&#xA;&gt; &gt;&gt; &gt;&gt;&gt; Michael Dubrovsky&#xA;&gt; &gt;&gt; &gt;&gt;&gt; Founder; PoWx&#xA;&gt; &gt;&gt; &gt;&gt;&gt; www.PoWx.org&#xA;&gt; &gt;&gt; &gt;&gt;&gt; _______________________________________________&#xA;&gt; &gt;&gt; &gt;&gt;&gt; bitcoin-dev mailing list&#xA;&gt; &gt;&gt; &gt;&gt;&gt; bitcoin-dev at lists.linuxfoundation.org&#xA;&gt; &gt;&gt; &gt;&gt;&gt; https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev&#xA;&gt; &gt;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; &gt;&gt; _______________________________________________&#xA;&gt; &gt;&gt; &gt;&gt; bitcoin-dev mailing list&#xA;&gt; &gt;&gt; &gt;&gt; bitcoin-dev at lists.linuxfoundation.org&#xA;&gt; &gt;&gt; &gt;&gt; https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev&#xA;&gt; &gt;&gt; &gt;&#xA;&gt; &gt;&gt; &gt; _______________________________________________&#xA;&gt; &gt;&gt; &gt; bitcoin-dev mailing list&#xA;&gt; &gt;&gt; &gt; bitcoin-dev at lists.linuxfoundation.org&#xA;&gt; &gt;&gt; &gt; https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev&#xA;&gt;&#xA;-------------- next part --------------&#xA;An HTML attachment was scrubbed...&#xA;URL: &lt;http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20210524/8f5565cc/attachment-0001.html&gt;</html></oembed>