Comments inline.
> > Could you explain what am I missing here, because this actually does not > > seem better, but rather worse than some PoS schemes? > > Given your example, if !BTC is needed to burn, that's a $50k > investment in an ASIC needed to mine a block. That's not anywhere > near current levels. It's not even approaching the current PoW. A > $50k investment to be a large amount of hash power is ... well, > somewhere more than 10 years ago. This is +- true with todays prices, that was not my point. We all know that today's total block revenue is nowhere near 1 BTC. If it is say 7 BTC, then we would expect that the miners spend roughly just about 7 BTC to produce the block - in long term, on average. Right? Today, this 7 BTC is supposed to be some average of investment into the mining rig, the building in which the rig exists (or its rent) and then some electricity. So when I said 1 BTC I meant that amount of BTC that is the sum of the block subsidy and fees at the time of this imagined switch to PoB. Use 7 BTC if you want to talk today. And yes, that seems very weak. But can you explain why it is not the case after switching to PoB that the cost of producing the block should roughly converge to to the revenue? Because I do not see why would miners spend more than what they can earn. > My original proof-of-burn concept was designed to mimic ASICs as much > as possible: > > 1. large initial investment (burn to acquire power) > 2. continued investment (burn to activate power in each block, lost if > block is not found) > > Ideally, the attacker would have to keep burning for each lottery > ticket, which can only be used once. Committing that burn to a > particular block for example. > > Any attack you propose for a "assumed well designed PoB" can also attack > PoW. > Any attack you propose for a "assumed well designed PoB" can also attack > PoS. > > But there are some things PoB can do that PoS can't... which is really > my original point. This is the problem that I wanted to avoid. You refer to some "my original PoB", but I am strictly talking about the concept described in wiki because nothing else was provided to me. If we do not have a reference description of what you are talking about the debate will quickly turn into the classical debate with PoS supporters - I explain an attack and they "patch it", creating problem elsewhere. Then I explain an attack against that and they patch it there. And this goes infinitely. So if there is some other version, better one than the one described in wiki, please let me know. If there is not, there is nothing to talk about really. You'd first need to define your model properly and describe very details of how it should work and then we can analyze it. It does not make much sense to me to analyze a ghost protocol that I always only see a tiny part of. For example here above in the quoted text you mention some continual lost (if block is not found). If that is not the exponential decay as described in the wiki, then I have no idea what it is. I do not say that I can't imagine for myself what it could be, but it is up to you to define it, so we can be sure we are talking about the same thing. Same with those early unblinding of burns - nothing about that in the wiki, so that concept is alien to me and it can not be subject to a debate before it is precisely described. > > > - sunk costs/lost investment > - "hashpower" is "offline", and cannot be seized. > > On Tue, Jun 1, 2021 at 4:21 AM befreeandopen > [email protected] wrote: > > > > Erik, thanks for the link. So referring to > > https://en.bitcoin.it/wiki/Proof_of_burn, I do not really understand how > > this is supposed to be that much better over many proof of stake proposals. > > If there is more research on PoB, please note I'm not commenting on that as > > I only read this wiki article and my comments are purely related to this > > only. > > I hope we can agree that the idea with manual insertion of entropy every > > week can be discarded, but at the same time I don't think it is a crucial > > point of the whole idea. So we can just focus on the rest of it. > > Then the whole idea seems just like certain proof of stake implementations > > with just small differences, which I try to summarize: > > > > - in PoB, in order to use the coin for block production, you burn it in > > the past and wait some time -- in the certain PoS I'm talking about, in > > order to use the coin, you do not move the coin for some time - so in both > > there is the same idea - you somehow make the coin eligible for the block > > creation process by first doing some action followed by some inaction for > > some time; the difference here is that if later you use such coin in PoS, > > then after waiting more time, you can use the coin again (for whatever > > purpose), while in PoB the coin is gone forever (it is burned); this does > > not seem to be fundamentally different > > > > - in PoB, the author suggests there is an exponential decay of the power > > of the coin to create a block; in some PoS schemas, there historically was > > an era of so called CoinAge mechanism, which was somewhat inverse to this > > exponential decay, it was that the coin gets more power the older it is > > untouched, some implementations were for linear increase in the power, some > > exponential. Usually there was a certain limit - i.e. a maximum power the > > coin may have reached. It turned out quite quickly that such property is > > making attacks easier. PoB reverses the idea, but I don't think that helps > > that much. In any case, there seems to be an optimal period of time for > > each used coin, in both PoS and PoB, where the coin is most suitable for > > block production. I admit PoB version is better, but the crucial property > > here is that some coins are more powerful than other. > > > > - in both PoB and PoS it seems there is linear increase of the ability of > > the coin to produce blocks with the size of the coin (more BTC you > > burn/stake, the better your chance) > > > > > > This characteristic of PoB does not suggest that it would have that much > > different properties than PoS. So it should suffer from same problems as > > PoS. Namely, the problems I see now, with the given proposal from wiki, are: > > > > - there seems to be lack of definition of the heaviest chain and > > difficulty adjustment - this seems crucial, but likely solvable, I'm just > > saying it is importantly missing in the description > > > > - there seems to be a problem with nothing at stake (nothing at burn > > maybe?) - How that can be? Again, it seems that every burned coin can be > > used for free checks at any time after the initial waiting period. These > > free checks are indeed free and are the core of the nothing at stake > > problem in PoS. You seem to make those checks for free and you seem to be > > able to use those burned coins to create arbitrary number of forks build on > > any parent blocks of your choice, not just the last block of the heaviest > > chain. I can't see at the moment how is this different from PoS nothing at > > stake problem. Maybe you can explain? > > > > - it seems to me that there is a trivial attack against the scheme by a > > wealthy attacker. Suppose a common size of the burn is 1 BTC per block, > > suppose you define the heaviest chain rule somehow in relation to total > > number of burned coins or the cumulative "strength" of the "lowest" hashes, > > then you can just burn 20 UTXOs, each being 10 BTC in value, so you spent > > 200 BTC on this attack, but you are in very strong position because after > > you wait the needed time, you should be able to do pretty nasty reorg. > > Suppose that the main chain is A-B-C-D-E-F, so what you do at that point is > > that you just "try for free" all your 20 UTXOs, whether or not they can > > build on top of block A (which has 5 confs on top, F is the tip of the main > > chain). Since you have big UTXOs, your chances should be good, of course > > you can always try many times because you have a "lottery ticket" for every > > timestampt t. So with this you should be able, with good chance, to find > > such B' and then you have 19 UTXOs remaining to try to build on B' in the > > same way. I can't see what prevents this attack in the described scheme. > > > > - the ability to retroactively try all different kids of timestamp t > > seems devastating - you again get super easy and somewhat cheap attack (due > > to nothing at burn problem) that allows you to rewrite even long chains at > > will. > > > > > > Could you explain what am I missing here, because this actually does not > > seem better, but rather worse than some PoS schemes? > > Sent with ProtonMail Secure Email. > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > On Friday, May 28, 2021 9:06 PM, Erik Aronesty [email protected] wrote: > > > > > best writeup i know of is here: > > > https://en.bitcoin.it/wiki/Proof_of_burn > > > no formal proposals or proofs that i know of. > > > On Fri, May 28, 2021 at 10:40 AM befreeandopen > > > [email protected] wrote: > > > > > > > Erik, I am sorry, I have little knowledge about proof-of-burn, I never > > > > found it interesting up until now. Some of your recent claims seem > > > > quite strong to me and I'd like to read more. > > > > Forgive me if this has been mentioned recently, but is there a full > > > > specification of the concept you are referring to? I don't mean just > > > > the basic idea description (that much is clear to me), I mean a fully > > > > detailed proposal or technical documentation that would give me a > > > > precise information about what exactly it is that you are talking about. > > > > Sent with ProtonMail Secure Email. > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > > > On Wednesday, May 26, 2021 11:07 PM, Erik Aronesty [email protected] wrote: > > > > > > > > > note: the "nothing at stake" problem you propose is not broken for > > > > > proof-of-burn, because the attacker > > > > > a) has no idea which past transactions are burns > > > > > b) has no way to use his mining power, even 5%, to maliciously improve > > > > > his odds of being selected > > > > > On Wed, May 26, 2021 at 9:12 AM befreeandopen > > > > > [email protected] wrote: > > > > > > > > > > > @befreeandopen I guess I misunderstood your selfish minting attack. > > > > > > Let me make sure I understand it. You're saying it would go as > > > > > > follows?: > > > > > > > > > > > > 1. The malicious actor comes across an opportunity to mint the > > > > > > next 3 blocks. But they hold off and don't release their blocks > > > > > > just yet. > > > > > > 2. They receive a new block minted by someone else. > > > > > > 3. The malicious actor then chooses to release their other 2 > > > > > > blocks on on the second from the top block if it gives them more > > > > > > blocks in the future than minting on the top block. And instead > > > > > > lets the top block proceed if it gives them more blocks in the > > > > > > future (also figuring in the 3 blocks they're missing out on > > > > > > minting). > > > > > > 4. Profit! > > > > > > > > > > > > The problem with this attack is that any self respecting PoS system > > > > > > wouldn't have the information available for minters to know how > > > > > > blocks will affect their future prospects of minting. Otherwise > > > > > > this would introduce the problem of stake grinding. This can be > > > > > > done using collaborative randomness (where numbers from many > > > > > > parties are combined to create a random number that no individual > > > > > > party could predict). In fact, that's what the Casper protocol does > > > > > > to decide quorums. In a non quorum case, you can do something like > > > > > > record a hash of a number in the block header, and then have a > > > > > > second step to release that number later. Rewards can be given can > > > > > > be used to ensure minters act honestly here by minting messages > > > > > > that release these numbers and not releasing their secret numbers > > > > > > too early. > > > > > > Yes, you misunderstood it. First, let me say that the above > > > > > > thoughts of yours are incorrect, at least for non-quorum case. > > > > > > Since the transition in the blockchain system from S1 to S2 is only > > > > > > by adding new block, and since stakers always need to be able to > > > > > > decide whether or not they can add the next block, it follows that > > > > > > if a staker creates a new block locally, she can decide whether the > > > > > > new state allows her to add another block on top. As you mentioned, > > > > > > this COULD introduce problem of staking, that you are incorrect in > > > > > > that it is a necessity. Usual prevention of the grinding problem in > > > > > > this case is that an "old enough" source of randomness applies for > > > > > > the current block production process. Of course this, as it is > > > > > > typical for PoS, introduces other problems, but let's discard those. > > > > > > I will try to explain in detail what you misunderstood before. You > > > > > > start with a chain ending with blocks A-B-C, C being the top, the > > > > > > common feature of PoS system (non-quorum), roughly speaking, is > > > > > > that if N is the total amount of coins that participate in the > > > > > > staking process to create a new block on top of C (let's call that > > > > > > D), then a participant having K*N amount of stake has chance K to > > > > > > be the one who will create the next stake. In other words, the > > > > > > power of stakers is supposed to be linear in the system - you own > > > > > > 10 coins gives you 10x the chance of finding block over someone who > > > > > > has 1 coin. > > > > > > What i was claiming is that using the technique I have described, > > > > > > this linearity is violated. Why? Well, it works for honest stakers > > > > > > among the competition of honest stakers - they really do have the > > > > > > chance of K to find the next block. However, the attacker, using > > > > > > nothing at stake, checks her ability to build block D (at some > > > > > > timestamp). If she is successful, she does not propagate D > > > > > > immediately, but instead she also checks whether she can build on > > > > > > top of B and on top of A. Since with every new timestamp, usually, > > > > > > there is a new chance to build the block, it is not uncommon that > > > > > > she finds she is indeed able to build such block C' on top of B. > > > > > > Here it is likely t(C') > t(C) as the attacker has relatively low > > > > > > stake. Note that in order to produce such C', she not only could > > > > > > have tried the current timestamp t(D), but also all previous > > > > > > timestamps up to t(B) (usually that's the consensus rule, but it > > > > > > may depend on a specific consensus). So her chance to produce such > > > > > > C' is greater than her previous chance of producing C (which chance > > > > > > was limited by other stakers in the system and the discovery of > > > > > > block C by one of them). Now suppose that she found such C' and now > > > > > > she continues by trying to prolong this chain by finding D'. And > > > > > > again here, it is quite likely that her chance to find such D' is > > > > > > greater than was her chance of finding D because again there are > > > > > > likely multiple timestamps she could try. This all was possible > > > > > > just because nothing at stake allows you to just try if you can > > > > > > produce a block in certain state of block chain or not. Now if she > > > > > > actually was able to find D', she discards D and only publishes > > > > > > chain A-B-C'-D', which can not be punished despite the fact that > > > > > > she indeed produced two different forks. She can not be punished > > > > > > because this production was local and only the final result of > > > > > > A-B-C'-D' was published, in which case she gained an extra block > > > > > > over the honest strategy which would only give her block D. > > > > > > Fun fact tho: there is an attack called the "selfish mining attack" > > > > > > for proof of work, and it reduces the security of PoW by at least > > > > > > 1/3rd. > > > > > > How is that relevant to our discussion? This is known research that > > > > > > has nothing to do with PoS except that it is often worse on PoS. > > > > > > > > > > > > > the problem is not as hard as you think > > > > > > > > > > > > I don't claim to know just how hard finding the IP address > > > > > > associated with a bitcoin address is. However, the DOS risk can be > > > > > > solved more completely by only allowing the owner of coins > > > > > > themselves to know whether they can mint a block. Eg by determining > > > > > > whether someone can mint a block based on their public key hidden > > > > > > behind hashes (as normal in addresses). Only when someone does in > > > > > > fact mint a block do they reveal their hidden public key in order > > > > > > to prove they are allowed to mint the block. > > > > > > This is true, but you are mixing quorum and non-quorum systems. My > > > > > > objection here was towards such system where I specifically said > > > > > > that the list of producers for next epoch is known up front and you > > > > > > confirmed that this is what you meant with "quorum" system. So in > > > > > > such system, I claimed, the known producer is the only target at > > > > > > any given point of time. This of course does not apply to any other > > > > > > type of system where future producers are not known. No need to > > > > > > dispute, again, something that was not claimed. > > > > > > > > > > > > > I agree that introduction of punishment itself does not imply > > > > > > > introducing a problem elsewhere (which I did not claim if you > > > > > > > reread my previous message) > > > > > > > > > > > > I'm glad we agree there. Perhaps I misunderstood what you meant by > > > > > > "you should not omit to mention that by doing so, typically, you > > > > > > have introduced another problem elsewhere." > > > > > > Perhaps you should quote the full sentence and not just a part of > > > > > > it: > > > > > > "Of course you can always change the rules in a way that a certain > > > > > > specific attack is not doable, but you should not omit to mention > > > > > > that by doing so, typically, you have introduced another problem > > > > > > elsewhere, or you have not solved it completely." > > > > > > You can parse this as: (CREATE PROBLEM ELSEWHERE) OR (NOT SOLVE IT > > > > > > COMPLETELY) > > > > > > In case of the punishment it was meant to be the not solve it > > > > > > completely part. > > > > > > Also "typically" does not imply always. > > > > > > But this parsing of English sentences for you seems very off topic > > > > > > here. My point is, in context of Bitcoin, reject such unsupported > > > > > > claims that PoS is a reasonable alternative to PoW, let's stick to > > > > > > that. > > > > > > > > > > > > > As long as the staker makes sure (which is not that hard) that > > > > > > > she does not miss a chance to create a block, her significance in > > > > > > > the system will always increase in time. It will increase > > > > > > > relative to all normal users who do not stake > > > > > > > > > > > > Well, if you're in the closed system of the cryptocurrency, sure. > > > > > > But we don't live in that closed system. Minters will earn some ROI > > > > > > from minting just like any other financial activity. Others may > > > > > > find more success spending their time doing things other than > > > > > > figuring out how to mint coins. In that case, they'll be able to > > > > > > earn more coin that they could later decide to use to mint blocks > > > > > > if they decide to. > > > > > > This only supports the point I was making. Since the optimal > > > > > > scenario with all existing coins participating is just theoretical, > > > > > > the attacker's position will ever so improve. It seems we are in > > > > > > agreement here, great. > > > > > > > > > > > > > Just because of the above we must reject PoS as being critically > > > > > > > insecure > > > > > > > > > > > > I think the only thing we can conclude from this is that you have > > > > > > come up with an insecure proof of stake protocol. I don't see how > > > > > > anything you've brought up amounts to substantial evidence that all > > > > > > possible PoS protocols are insecure. > > > > > > I have not come up with anything. I'm afraid you've not realized > > > > > > the burden of proof is on your side if you vouch for a design that > > > > > > is not believed and trusted to be secure. It is up to you to show > > > > > > that you know how to solve every problem that people throw at you. > > > > > > So far we have just demonstrated that your claim that nothing at > > > > > > stake is solved was unjustified. You have not described a system > > > > > > that would solve it (and not introduce critical DDOS attack vector > > > > > > as it is in quorum based systems - per the prior definition of such > > > > > > systems). > > > > > > Of course the list of problems of PoS systems do not end with just > > > > > > nothing at stake, but it is good enough example that by itself > > > > > > prevents its adoption in decentralized consensus. No need to go to > > > > > > other hard problems without solving nothing at stake. > > > > > > On Tue, May 25, 2021 at 11:10 AM befreeandopen > > > > > > [email protected] wrote: > > > > > > > > > > > > > @befreeandopen " An attacker can calculate whether or not she can > > > > > > > prolong this chain or not and if so with what timestamp." > > > > > > > The scenario you describe would only be likely to happen at all > > > > > > > if the malicious actor has a very large fraction of the stake - > > > > > > > probably quite close to 50%. At that point, you're talking about > > > > > > > a 51% attack, not the nothing at stake problem. The nothing at > > > > > > > stake problem is the problem where anyone will mint on any chain. > > > > > > > Its clear that if there's a substantial punishment for minting on > > > > > > > chains other than the one that eventually wins, every minter > > > > > > > without a significant fraction of the stake will be honest and > > > > > > > not attempt to mint on old blocks or support someone else's > > > > > > > attempt to mint on old blocks (until and if it becomes the > > > > > > > heaviest chain). Because the attacker would need probably >45% of > > > > > > > the active stake (take a look at the reasoning here for a deeper > > > > > > > analysis of that statement), I don't agree that punishment is not > > > > > > > a sufficient mitigation of the nothing at stake problem. To > > > > > > > exploit the nothing at stake problem, you basically need to 51% > > > > > > > attack, at which point you've exceeded the operating conditions > > > > > > > of the system, so of course its gonna have problems, just like a > > > > > > > 51% attack would cause with PoW. > > > > > > > This is not at all the case. The attacker benefits using the > > > > > > > described technique at any size of the stake and significantly so > > > > > > > with just 5% of the stake. By significantly, I do not mean that > > > > > > > the attacker is able to completely take control the network (in > > > > > > > short term), but rather that the attacker has significant > > > > > > > advantage in the number of blocks she creates compared to what > > > > > > > she "should be able to create". This means the attacker's stake > > > > > > > increases significantly faster than of the honest nodes, which in > > > > > > > long term is very serious in PoS system. If you believe close to > > > > > > > 50% is needed for that, you need to redo your math. So no, you > > > > > > > are wrong stating that "to exploit nothing at stake problem you > > > > > > > basically need to 51% attack". It is rather the opposite - > > > > > > > eventually, nothing at stake attack leads to ability to perform > > > > > > > 51% attack. > > > > > > > > > > > > > > > I am not sure if this is what you call quorum-based PoS > > > > > > > > > > > > > > Yes, pre-selected minters is exactly what I mean by that. > > > > > > > > > > > > > > > it allows the attacker to know who to attack at which point > > > > > > > > with powerful DDOS in order to hurt liveness of such system > > > > > > > > > > > > > > Just like in bitcoin, associating keys with IP addresses isn't > > > > > > > generally an easy thing to do on the fly like that. If you know > > > > > > > someone's IP address, you can target them. But if you only know > > > > > > > their address or public key, the reverse isn't as easy. With a > > > > > > > quorum-based PoS system, you can see their public key and > > > > > > > address, but finding out their IP to DOS would be a huge > > > > > > > challenge I think. > > > > > > > I do not dispute that the problem is not trivial, but the problem > > > > > > > is not as hard as you think. The network graph analysis is a > > > > > > > known technique and it is not trivial, but not very hard either. > > > > > > > Introducing a large number of nodes to the system to achieve very > > > > > > > good success rate of analysis of area of origin of blocks is > > > > > > > doable and has been done in past. So again, I very much disagree > > > > > > > with your conclusion that this is somehow secure. It is > > > > > > > absolutely insecure. > > > > > > > Note, tho, that quorum-based PoS generally also have punishments > > > > > > > as part of the protocol. The introduction of punishments do > > > > > > > indeed handily solve the nothing at stake problem. And you didn't > > > > > > > mention a single problem that the punishments introduce that > > > > > > > weren't already there before punishments. There are tradeoffs > > > > > > > with introducing punishments (eg in some cases you might punish > > > > > > > honest actors), but they are minor in comparison to solving the > > > > > > > nothing at stake problem. > > > > > > > While I agree that introduction of punishment itself does not > > > > > > > imply introducing a problem elsewhere (which I did not claim if > > > > > > > you reread my previous message), it does introduce additional > > > > > > > complexity which may introduce problem, but more importantly, > > > > > > > while it slightly improves resistance against the nothing at > > > > > > > stake attack, it solves absolutely nothing. Your claim is based > > > > > > > on wrong claim of needed close to 50% stake, but that could not > > > > > > > be farther from the truth. It is not true even in optimal > > > > > > > conditions when all participants of the network stake or delegate > > > > > > > their stake. These optimal conditions rarely, if ever, occur. And > > > > > > > that's another thing that we have not mention in our debate, so > > > > > > > please allow me to introduce another problem to PoS. > > > > > > > Consider what is needed for such optimal conditions to occur - > > > > > > > all coins are always part of the stake, which means that they > > > > > > > need to somehow automatically part of the staking process even > > > > > > > when they are moved. But in many PoS systems you usually require > > > > > > > some age (in terms of confirmations) of the coin before you allow > > > > > > > it to be used for participation in staking process and that is > > > > > > > for a good reason - to prevent various grinding attacks. In some > > > > > > > systems the coin must be specifically registered before it can be > > > > > > > staked, in others, simply waiting for enough confirmations > > > > > > > enables you to stake with the coin. I am not sure if there is a > > > > > > > system which does not have this cooling period for a coin that > > > > > > > has been moved. Maybe it is possible though, but AFAIK it is not > > > > > > > common and not battle tested feature. > > > > > > > Then if we admit that achieving the optimal condition is rather > > > > > > > theoretical. Then if we do not have the optimal condition, it > > > > > > > means that a staker with K% of the total available supply > > > > > > > increases it's percentage over time to some amounts >K%. As long > > > > > > > as the staker makes sure (which is not that hard) that she does > > > > > > > not miss a chance to create a block, her significance in the > > > > > > > system will always increase in time. It will increase relative to > > > > > > > all normal users who do not stake (if there are any) and relative > > > > > > > to all other stakers who make mistakes or who are not wealthy > > > > > > > enough to afford not selling any position ever. But powerful > > > > > > > attacker is exactly in such position and thus she will gain > > > > > > > significance in such a system. The technique I have described, > > > > > > > and that you mistakenly think is viable only with huge amounts of > > > > > > > stake, only puts the attacker to even greater advantage. But even > > > > > > > without the described attack (which exploits nothing at stake), > > > > > > > the PoS system converges to a system more and more controlled by > > > > > > > powerful entity, which we can assume is the attacker. > > > > > > > So I don't think it is at all misleading to claim that "nothing > > > > > > > at stake" is a solved problem. I do in fact mean that the > > > > > > > solutions to that problem don't introduce any other problems with > > > > > > > anywhere near the same level of significance. > > > > > > > It still stands as truly misleading claim. I disagree that > > > > > > > introducing DDOS opportunity with medium level of difficulty for > > > > > > > the attacker to implement it, in case of "quorum-based PoS" is > > > > > > > not a problem anywhere near the same level of significance. Such > > > > > > > an attack vector allows you to turn off the network if you spend > > > > > > > some time and money. That is hardly acceptable. > > > > > > > Just because of the above we must reject PoS as being critically > > > > > > > insecure until someone invents and demonstrates an actual way of > > > > > > > solving these issues. > > > > > > > On Tue, May 25, 2021 at 3:00 AM Erik Aronesty [email protected] wrote: > > > > > > > > > > > > > > > > > you burn them to be used at a future particular block height > > > > > > > > > > > > > > > > > This sounds exploitable. It seems like an attacker could > > > > > > > > > simply focus all their burns on a particular set of 6 blocks > > > > > > > > > to double spend, minimizing their cost of attack. > > > > > > > > > > > > > > > > could be right. the original idea was to have burns decay over > > > > > > > > time, > > > > > > > > like ASIC's. > > > > > > > > anyway the point was not that "i had a magic formula" > > > > > > > > the point was that proof of burn is almost always better than > > > > > > > > proof of > > > > > > > > stake - simply because the "proof" is on-chain, not sitting on > > > > > > > > a node > > > > > > > > somewhere waiting to be stolen. > > > > > > > > On Mon, May 24, 2021 at 9:53 PM Billy Tetrud > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > Is this the kind of proof of burn you're talking about? > > > > > > > > > > > > > > > > > > > if i have a choice between two chains, one longer and one > > > > > > > > > > shorter, i can only choose one... deterministically > > > > > > > > > > > > > > > > > > What prevents you from attempting to mine block 553 on both > > > > > > > > > chains? > > > > > > > > > > > > > > > > > > > miners have a very strong, long-term, investment in the > > > > > > > > > > stability of the chain. > > > > > > > > > > > > > > > > > > Yes, but the same can be said of any coin, even ones that do > > > > > > > > > have the nothing at stake problem. This isn't sufficient tho > > > > > > > > > because the chain is a common good, and the tragedy of the > > > > > > > > > commons holds for it. > > > > > > > > > > > > > > > > > > > you burn them to be used at a future particular block height > > > > > > > > > > > > > > > > > > This sounds exploitable. It seems like an attacker could > > > > > > > > > simply focus all their burns on a particular set of 6 blocks > > > > > > > > > to double spend, minimizing their cost of attack. > > > > > > > > > > > > > > > > > > > i can imagine scenarios where large stakeholders can > > > > > > > > > > collude to punish smaller stakeholders simply to drive them > > > > > > > > > > out of business, for example > > > > > > > > > > > > > > > > > > Are you talking about a 51% attack? This is possible in any > > > > > > > > > decentralized cryptocurrency. > > > > > > > > > On Mon, May 24, 2021 at 11:49 AM Erik Aronesty [email protected] > > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > > > your burn investment is always "at stake", any > > > > > > > > > > > > redaction can result in a loss-of-burn, because burns > > > > > > > > > > > > can be tied, precisely, to block-heights > > > > > > > > > > > > I'm fuzzy on how proof of burn works. > > > > > > > > > > > > > > > > > > > > when you burn coins, you burn them to be used at a future > > > > > > > > > > particular > > > > > > > > > > block height: so if i'm burning for block 553, i can only > > > > > > > > > > use them to > > > > > > > > > > mine block 553. if i have a choice between two chains, one > > > > > > > > > > longer > > > > > > > > > > and one shorter, i can only choose one... > > > > > > > > > > deterministically, for that > > > > > > > > > > burn: the chain with the height 553. if we fix the "lead > > > > > > > > > > time" for > > > > > > > > > > burned coins to be weeks or even months in advance, miners > > > > > > > > > > have a very > > > > > > > > > > strong, long-term, investment in the stability of the chain. > > > > > > > > > > therefore there is no "nothing at stake" problem. it's > > > > > > > > > > deterministic, so miners have no choice. they can only > > > > > > > > > > choose the > > > > > > > > > > transactions that go into the block. they cannot choose > > > > > > > > > > which chain > > > > > > > > > > to mine, and it's time-locked, so rollbacks and instability > > > > > > > > > > always > > > > > > > > > > hurt miners the most. > > > > > > > > > > the "punishment" systems of PoS are "weird at best", > > > > > > > > > > certainly > > > > > > > > > > unproven. i can imagine scenarios where large stakeholders > > > > > > > > > > can > > > > > > > > > > collude to punish smaller stakeholders simply to drive them > > > > > > > > > > out of > > > > > > > > > > business, for example. and then you have to put checks in > > > > > > > > > > place to > > > > > > > > > > prevent that, and more checks for those prevention system... > > > > > > > > > > in PoB, there is no complexity. simpler systems like this > > > > > > > > > > are > > > > > > > > > > typically more secure. > > > > > > > > > > PoB also solves problems caused by "energy dependence", > > > > > > > > > > which could > > > > > > > > > > lead to state monopolies on mining (like the new Bitcoin > > > > > > > > > > Mining > > > > > > > > > > Council). these consortiums, if state sanctioned, could > > > > > > > > > > become a > > > > > > > > > > source of censorship, for example. Since PoB doesn't > > > > > > > > > > require you to > > > > > > > > > > have a live, well-connected node, it's harder to censor & > > > > > > > > > > harder to > > > > > > > > > > trace. > > > > > > > > > > Eliminating this weakness seems to be in the best interests > > > > > > > > > > of > > > > > > > > > > existing stakeholders > > > > > > > > > > On Mon, May 24, 2021 at 4:44 PM Billy Tetrud > > > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > proof of burn clearly solves this, since nothing is > > > > > > > > > > > > held online > > > > > > > > > > > > > > > > > > > > > > Well.. the coins to be burned need to be online when > > > > > > > > > > > they're burned. But yes, only a small fraction of the > > > > > > > > > > > total coins need to be online. > > > > > > > > > > > > > > > > > > > > > > > your burn investment is always "at stake", any > > > > > > > > > > > > redaction can result in a loss-of-burn, because burns > > > > > > > > > > > > can be tied, precisely, to block-heights > > > > > > > > > > > > > > > > > > > > > > So you're saying that if say someone tries to mine a > > > > > > > > > > > block on a shorter chain, that requires them to send a > > > > > > > > > > > transaction burning their coins, and that transaction > > > > > > > > > > > could also be spent on the longest chain, which means > > > > > > > > > > > their coins are burned even if the chain they tried to > > > > > > > > > > > mine on doesn't win? I'm fuzzy on how proof of burn works. > > > > > > > > > > > > > > > > > > > > > > > proof of burn can be more secure than proof-of-stake > > > > > > > > > > > > > > > > > > > > > > FYI, proof of stake can be done without the "nothing at > > > > > > > > > > > stake" problem. You can simply punish people who mint on > > > > > > > > > > > shorter chains (by rewarding people who publish proofs of > > > > > > > > > > > this happening on the main chain). In quorum-based PoS, > > > > > > > > > > > you can punish people in the quorum that propose or sign > > > > > > > > > > > multiple blocks for the same height. The "nothing at > > > > > > > > > > > stake" problem is a solved problem at this point for PoS. > > > > > > > > > > > On Mon, May 24, 2021 at 3:47 AM Erik Aronesty > > > > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > I don't see a way to get around the conflicting > > > > > > > > > > > > > requirement that the keys for large amounts of coins > > > > > > > > > > > > > should be kept offline but those are exactly the > > > > > > > > > > > > > coins we need online to make the scheme secure. > > > > > > > > > > > > > > > > > > > > > > > > proof of burn clearly solves this, since nothing is > > > > > > > > > > > > held online > > > > > > > > > > > > > > > > > > > > > > > > > how does proof of burn solve the "nothing at stake" > > > > > > > > > > > > > problem in your view? > > > > > > > > > > > > > > > > > > > > > > > > definition of nothing at stake: in the event of a fork, > > > > > > > > > > > > whether the > > > > > > > > > > > > fork is accidental or a malicious, the optimal strategy > > > > > > > > > > > > for any miner > > > > > > > > > > > > is to mine on every chain, so that the miner gets their > > > > > > > > > > > > reward no > > > > > > > > > > > > matter which fork wins. indeed in proof-of-stake, the > > > > > > > > > > > > proofs are > > > > > > > > > > > > published on the very chains mines, so the incentive is > > > > > > > > > > > > magnified. > > > > > > > > > > > > in proof-of-burn, your burn investment is always "at > > > > > > > > > > > > stake", any > > > > > > > > > > > > redaction can result in a loss-of-burn, because burns > > > > > > > > > > > > can be tied, > > > > > > > > > > > > precisely, to block-heights > > > > > > > > > > > > as a result, miners no longer have an incentive to mine > > > > > > > > > > > > all chains > > > > > > > > > > > > in this way proof of burn can be more secure than > > > > > > > > > > > > proof-of-stake, and > > > > > > > > > > > > even more secure than proof of work > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Sun, May 23, 2021 at 3:52 AM Lloyd Fournier via > > > > > > > > > > > > bitcoin-dev > > > > > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > Hi Billy, > > > > > > > > > > > > > I was going to write a post which started by > > > > > > > > > > > > > dismissing many of the weak arguments that are made > > > > > > > > > > > > > against PoS made in this thread and elsewhere. > > > > > > > > > > > > > Although I don't agree with all your points you have > > > > > > > > > > > > > done a decent job here so I'll focus on the second > > > > > > > > > > > > > part: why I think Proof-of-Stake is inappropriate for > > > > > > > > > > > > > a Bitcoin-like system. > > > > > > > > > > > > > Proof of stake is not fit for purpose for a global > > > > > > > > > > > > > settlement layer in a pure digital asset (i.e. > > > > > > > > > > > > > "digital gold") which is what Bitcoin is trying to be. > > > > > > > > > > > > > PoS necessarily gives responsibilities to the holders > > > > > > > > > > > > > of coins that they do not want and cannot handle. > > > > > > > > > > > > > In Bitcoin, large unsophisticated coin holders can > > > > > > > > > > > > > put their coins in cold storage without a second > > > > > > > > > > > > > thought given to the health of the underlying ledger. > > > > > > > > > > > > > As much as hardcore Bitcoiners try to convince them > > > > > > > > > > > > > to run their own node, most don't, and that's > > > > > > > > > > > > > perfectly acceptable. > > > > > > > > > > > > > At no point do their personal decisions affect the > > > > > > > > > > > > > underlying consensus -- it only affects their > > > > > > > > > > > > > personal security assurance (not that of the system > > > > > > > > > > > > > itself). > > > > > > > > > > > > > In PoS systems this clean separation of > > > > > > > > > > > > > responsibilities does not exist. > > > > > > > > > > > > > I think that the more rigorously studied PoS > > > > > > > > > > > > > protocols will work fine within the security claims > > > > > > > > > > > > > made in their papers. > > > > > > > > > > > > > People who believe that these protocols are destined > > > > > > > > > > > > > for catastrophic consensus failure are certainly in > > > > > > > > > > > > > for a surprise. > > > > > > > > > > > > > But the devil is in the detail. > > > > > > > > > > > > > Let's look at what the implications of using the > > > > > > > > > > > > > leading proof of stake protocols would have on > > > > > > > > > > > > > Bitcoin: > > > > > > > > > > > > > > > > > > > > > > > > > > ### Proof of SquareSpace (Cardano, Polkdadot) > > > > > > > > > > > > > > > > > > > > > > > > > > Cardano is a UTXO based PoS coin based on Ouroboros > > > > > > > > > > > > > Praos3 with an inbuilt on-chain delegation system5. > > > > > > > > > > > > > In these protocols, coin holders who do not want to > > > > > > > > > > > > > run their node with their hot keys in it delegate it > > > > > > > > > > > > > to a "Stake Pool". > > > > > > > > > > > > > I call the resulting system Proof-of-SquareSpace > > > > > > > > > > > > > since most will choose a pool by looking around for > > > > > > > > > > > > > one with a nice website and offering the largest > > > > > > > > > > > > > share of the block reward. > > > > > > > > > > > > > On the surface this might sound no different than > > > > > > > > > > > > > someone with an mining rig shopping around for a good > > > > > > > > > > > > > mining pool but there are crucial differences: > > > > > > > > > > > > > > > > > > > > > > > > > > 1. The person making the decision is forced into it > > > > > > > > > > > > > just because they own the currency -- someone with a > > > > > > > > > > > > > mining rig has purchased it with the intent to make > > > > > > > > > > > > > profit by participating in consensus. > > > > > > > > > > > > > > > > > > > > > > > > > > 2. When you join a mining pool your systems are very > > > > > > > > > > > > > much still online. You are just partaking in a pool > > > > > > > > > > > > > to reduce your profit variance. You still see every > > > > > > > > > > > > > block that you help create and you never help create > > > > > > > > > > > > > a block without seeing it first. > > > > > > > > > > > > > > > > > > > > > > > > > > 3. If by SquareSpace sybil attack you gain a > > > > > > > > > > > > > dishonest majority and start censoring transactions > > > > > > > > > > > > > how are the users meant to redelegate their stake to > > > > > > > > > > > > > honest pools? > > > > > > > > > > > > > I guess they can just send a transaction > > > > > > > > > > > > > delegating to another pool...oh wait I guess that > > > > > > > > > > > > > might be censored too! This seems really really bad. > > > > > > > > > > > > > In Bitcoin, miners can just join a different pool > > > > > > > > > > > > > at a whim. There is nothing the attacker can do to > > > > > > > > > > > > > stop them. A temporary dishonest majority heals > > > > > > > > > > > > > relatively well. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > There is another severe disadvantage to this on-chain > > > > > > > > > > > > > delegation system: every UTXO must indicate which > > > > > > > > > > > > > staking account this UTXO belongs to so the > > > > > > > > > > > > > appropriate share of block rewards can be transferred > > > > > > > > > > > > > there. > > > > > > > > > > > > > Being able to associate every UTXO to an account > > > > > > > > > > > > > ruins one of the main privacy advantages of the UTXO > > > > > > > > > > > > > model. > > > > > > > > > > > > > It also grows the size of the blockchain > > > > > > > > > > > > > significantly. > > > > > > > > > > > > > > > > > > > > > > > > > > ### "Pure" proof of stake (Algorand) > > > > > > > > > > > > > > > > > > > > > > > > > > Algorand's4 approach is to only allow online stake to > > > > > > > > > > > > > participate in the protocol. > > > > > > > > > > > > > Theoretically, This means that keys holding funds > > > > > > > > > > > > > have to be online in order for them to author blocks > > > > > > > > > > > > > when they are chosen. > > > > > > > > > > > > > Of course in reality no one wants to keep their coin > > > > > > > > > > > > > holding keys online so in Alogorand you can authorize > > > > > > > > > > > > > a set of "participation keys"1 that will be used to > > > > > > > > > > > > > create blocks on your coin holding key's behalf. > > > > > > > > > > > > > Hopefully you've spotted the problem. > > > > > > > > > > > > > You can send your participation keys to any malicious > > > > > > > > > > > > > party with a nice website (see random example 2) > > > > > > > > > > > > > offering you a good return. > > > > > > > > > > > > > Damn it's still Proof-of-SquareSpace! > > > > > > > > > > > > > The minor advantage is that at least the > > > > > > > > > > > > > participation keys expire after a certain amount of > > > > > > > > > > > > > time so eventually the SquareSpace attacker will lose > > > > > > > > > > > > > their hold on consensus. > > > > > > > > > > > > > Importantly there is also less junk on the blockchain > > > > > > > > > > > > > because the participation keys are delegated > > > > > > > > > > > > > off-chain and so are not making as much of a mess. > > > > > > > > > > > > > > > > > > > > > > > > > > ### Conclusion > > > > > > > > > > > > > > > > > > > > > > > > > > I don't see a way to get around the conflicting > > > > > > > > > > > > > requirement that the keys for large amounts of coins > > > > > > > > > > > > > should be kept offline but those are exactly the > > > > > > > > > > > > > coins we need online to make the scheme secure. > > > > > > > > > > > > > If we allow delegation then we open up a new social > > > > > > > > > > > > > attack surface and it degenerates to > > > > > > > > > > > > > Proof-of-SquareSpace. > > > > > > > > > > > > > For a "digital gold" like system like Bitcoin we > > > > > > > > > > > > > optimize for simplicity and desperately want to avoid > > > > > > > > > > > > > extraneous responsibilities for the holder of the > > > > > > > > > > > > > coin. > > > > > > > > > > > > > After all, gold is an inert element on the periodic > > > > > > > > > > > > > table that doesn't confer responsibilities on the > > > > > > > > > > > > > holder to maintain the quality of all the other bars > > > > > > > > > > > > > of gold out there. > > > > > > > > > > > > > Bitcoin feels like this too and in many ways is more > > > > > > > > > > > > > inert and beautifully boring than gold. > > > > > > > > > > > > > For Bitcoin to succeed I think we need to keep it > > > > > > > > > > > > > that way and Proof-of-Stake makes everything a bit > > > > > > > > > > > > > too exciting. > > > > > > > > > > > > > I suppose in the end the market will decide what is > > > > > > > > > > > > > real digital gold and whether these bad technical > > > > > > > > > > > > > trade offs are worth being able to say it uses less > > > > > > > > > > > > > electricity. It goes without saying that making bad > > > > > > > > > > > > > technical decisions to appease the current political > > > > > > > > > > > > > climate is an anathema to Bitcoin. > > > > > > > > > > > > > Would be interested to know if you or others think > > > > > > > > > > > > > differently on these points. > > > > > > > > > > > > > Cheers, > > > > > > > > > > > > > LL > > > > > > > > > > > > > On Fri, 21 May 2021 at 19:21, Billy Tetrud via > > > > > > > > > > > > > bitcoin-dev [email protected] > > > > > > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > I think there is a lot of misinformation and bias > > > > > > > > > > > > > > against Proof of Stake. Yes there have been lots of > > > > > > > > > > > > > > shady coins that use insecure PoS mechanisms. Yes > > > > > > > > > > > > > > there have been massive issues with distribution of > > > > > > > > > > > > > > PoS coins (of course there have also been massive > > > > > > > > > > > > > > issues with PoW coins as well). However, I want to > > > > > > > > > > > > > > remind everyone that there is a difference between > > > > > > > > > > > > > > "proved to be impossible" and "have not achieved > > > > > > > > > > > > > > recognized success yet". Most of the arguments > > > > > > > > > > > > > > levied against PoS are out of date or rely on > > > > > > > > > > > > > > unproven assumptions or extrapolation from the > > > > > > > > > > > > > > analysis of a particular PoS system. I certainly > > > > > > > > > > > > > > don't think we should experiment with bitcoin by > > > > > > > > > > > > > > switching to PoS, but from my research, it seems > > > > > > > > > > > > > > very likely that there is a proof of stake > > > > > > > > > > > > > > consensus protocol we could build that has > > > > > > > > > > > > > > substantially higher security (cost / capital > > > > > > > > > > > > > > required to execute an attack) while at the same > > > > > > > > > > > > > > time costing far less resources (which do translate > > > > > > > > > > > > > > to fees on the network) without compromising any of > > > > > > > > > > > > > > the critical security properties bitcoin relies on. > > > > > > > > > > > > > > I think the critical piece of this is the > > > > > > > > > > > > > > disagreements around hardcoded checkpoints, which > > > > > > > > > > > > > > is a critical piece solving attacks that could be > > > > > > > > > > > > > > levied on a PoS chain, and how that does (or > > > > > > > > > > > > > > doesn't) affect the security model. > > > > > > > > > > > > > > @Eric Your proof of stake fallacy seems to be > > > > > > > > > > > > > > saying that PoS is worse when a 51% attack happens. > > > > > > > > > > > > > > While I agree, I think that line of thinking omits > > > > > > > > > > > > > > important facts: > > > > > > > > > > > > > > > > > > > > > > > > > > > > - The capital required to 51% attack a PoS chain > > > > > > > > > > > > > > can be made substantially greater than on a PoS > > > > > > > > > > > > > > chain. > > > > > > > > > > > > > > - The capital the attacker stands to lose can be > > > > > > > > > > > > > > substantially greater as well if the attack is > > > > > > > > > > > > > > successful. > > > > > > > > > > > > > > - The effectiveness of paying miners to raise the > > > > > > > > > > > > > > honest fraction of miners above 50% may be quite > > > > > > > > > > > > > > bad. > > > > > > > > > > > > > > - Allowing a 51% attack is already unacceptable. > > > > > > > > > > > > > > It should be considered whether what happens in the > > > > > > > > > > > > > > case of a 51% may not be significantly different. > > > > > > > > > > > > > > The currency would likely be critically damaged in > > > > > > > > > > > > > > a 51% attack regardless of consensus mechanism. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Proof-of-stake tends towards oligopolistic control > > > > > > > > > > > > > > > > > > > > > > > > > > > > People repeat this often, but the facts support > > > > > > > > > > > > > > this. There is no centralization pressure in any > > > > > > > > > > > > > > proof of stake mechanism that I'm aware of. IE if > > > > > > > > > > > > > > you have 10 times as much coin that you use to mint > > > > > > > > > > > > > > blocks, you should expect to earn 10x as much > > > > > > > > > > > > > > minting revenue - not more than 10x. By contrast, > > > > > > > > > > > > > > proof of work does in fact have clear > > > > > > > > > > > > > > centralization pressure - this is not disputed. Our > > > > > > > > > > > > > > goal in relation to that is to ensure that the > > > > > > > > > > > > > > centralization pressure remains insignifiant. Proof > > > > > > > > > > > > > > of work also clearly has a lot more barriers to > > > > > > > > > > > > > > entry than any proof of stake system does. Both of > > > > > > > > > > > > > > these mean the tendency towards oligopolistic > > > > > > > > > > > > > > control is worse for PoW. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Energy usage, in-and-of-itself, is nothing to be > > > > > > > > > > > > > > > ashamed of!! > > > > > > > > > > > > > > > > > > > > > > > > > > > > I certainly agree. Bitcoin's energy usage at the > > > > > > > > > > > > > > moment is I think quite warranted. However, the > > > > > > > > > > > > > > question is: can we do substantially better. I > > > > > > > > > > > > > > think if we can, we probably should... eventually. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Proof of Stake is only resilient to ⅓ of the > > > > > > > > > > > > > > > network demonstrating a Byzantine Fault, whilst > > > > > > > > > > > > > > > Proof of Work is resilient up to the ½ threshold > > > > > > > > > > > > > > > > > > > > > > > > > > > > I see no mention of this in the pos.pdf you linked > > > > > > > > > > > > > > to. I'm not aware of any proof that all PoS systems > > > > > > > > > > > > > > have a failure threshold of 1/3. I know that > > > > > > > > > > > > > > staking systems like Casper do in fact have that > > > > > > > > > > > > > > 1/3 requirement. However there are PoS designs that > > > > > > > > > > > > > > should exceed that up to nearly 50% as far as I'm > > > > > > > > > > > > > > aware. Proof of work is not in fact resilient up to > > > > > > > > > > > > > > the 1/2 threshold in the way you would think. IE, > > > > > > > > > > > > > > if 100% of miners are currently honest and have a > > > > > > > > > > > > > > collective 100 exahashes/s hashpower, an attacker > > > > > > > > > > > > > > does not need to obtain 100 exahashes/s, but > > > > > > > > > > > > > > actually only needs to accumulate 50 exahashes/s. > > > > > > > > > > > > > > This is because as the attacker accumulates > > > > > > > > > > > > > > hashpower, it drives honest miners out of the > > > > > > > > > > > > > > market as the difficulty increases to beyond what > > > > > > > > > > > > > > is economically sustainable. Also, its been shown > > > > > > > > > > > > > > that the best proof of work can do is require an > > > > > > > > > > > > > > attacker to obtain 33% of the hashpower because of > > > > > > > > > > > > > > the selfish mining attack discussed in depth in > > > > > > > > > > > > > > this paper: https://arxiv.org/abs/1311.0243. > > > > > > > > > > > > > > Together, both of these things reduce PoW's > > > > > > > > > > > > > > security by a factor of about 83% (1 - 50%*33%). > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Proof of Stake requires other trade-offs which > > > > > > > > > > > > > > > are incompatible with Bitcoin's objective (to be > > > > > > > > > > > > > > > a trustless digital cash) — specifically the > > > > > > > > > > > > > > > famous "security vs. liveness" guarantee > > > > > > > > > > > > > > > > > > > > > > > > > > > > Do you have a good source that talks about why you > > > > > > > > > > > > > > think proof of stake cannot be used for a trustless > > > > > > > > > > > > > > digital cash? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > You cannot gain tokens without someone choosing > > > > > > > > > > > > > > > to give up those coins - a form of permission. > > > > > > > > > > > > > > > > > > > > > > > > > > > > This is not a practical constraint. Just like in > > > > > > > > > > > > > > mining, some nodes may reject you, but there will > > > > > > > > > > > > > > likely be more that will accept you, some sellers > > > > > > > > > > > > > > may reject you, but most would accept your money as > > > > > > > > > > > > > > payment for bitcoins. I don't think requiring the > > > > > > > > > > > > > > "permission" of one of millions of people in the > > > > > > > > > > > > > > market can be reasonably considered a "permissioned > > > > > > > > > > > > > > currency". > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 2. Proof of stake must have a trusted means of > > > > > > > > > > > > > > > timestamping to regulate overproduction of blocks > > > > > > > > > > > > > > > > > > > > > > > > > > > > Both PoW and PoS could mine/mint blocks twice as > > > > > > > > > > > > > > fast if everyone agreed to double their clock > > > > > > > > > > > > > > speeds. Both systems rely on an honest majority > > > > > > > > > > > > > > sticking to standard time. > > > > > > > > > > > > > > On Wed, May 19, 2021 at 5:32 AM Michael Dubrovsky > > > > > > > > > > > > > > via bitcoin-dev > > > > > > > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Ah sorry, I didn't realize this was, in fact, a > > > > > > > > > > > > > > > different thread! :) > > > > > > > > > > > > > > > On Wed, May 19, 2021 at 10:07 AM Michael > > > > > > > > > > > > > > > Dubrovsky [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Folks, I suggest we keep the discussion to PoW, > > > > > > > > > > > > > > > > oPoW, and the BIP itself. PoS, VDFs, and so on > > > > > > > > > > > > > > > > are interesting but I guess there are other > > > > > > > > > > > > > > > > threads going on these topics already where > > > > > > > > > > > > > > > > they would be relevant. > > > > > > > > > > > > > > > > Also, it's important to distinguish between > > > > > > > > > > > > > > > > oPoW and these other "alternatives" to > > > > > > > > > > > > > > > > Hashcash. oPoW is a true Proof of Work that > > > > > > > > > > > > > > > > doesn't alter the core game theory or security > > > > > > > > > > > > > > > > assumptions of Hashcash and actually contains > > > > > > > > > > > > > > > > SHA (can be SHA3, SHA256, etc hash is > > > > > > > > > > > > > > > > interchangeable). > > > > > > > > > > > > > > > > Cheers, > > > > > > > > > > > > > > > > Mike > > > > > > > > > > > > > > > > On Tue, May 18, 2021 at 4:55 PM Erik Aronesty > > > > > > > > > > > > > > > > via bitcoin-dev > > > > > > > > > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 1. i never suggested vdf's to replace pow. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 2. my suggestion was specifically in the > > > > > > > > > > > > > > > > > context of a working > > > > > > > > > > > > > > > > > proof-of-burn protocol > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > - vdfs used only for timing (not block > > > > > > > > > > > > > > > > > height) > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > - blind-burned coins of a specific age used > > > > > > > > > > > > > > > > > to replace proof of work > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > - the required "work" per block would > > > > > > > > > > > > > > > > > simply be a competition to > > > > > > > > > > > > > > > > > acquire rewards, and so miners would have > > > > > > > > > > > > > > > > > to burn coins, well in > > > > > > > > > > > > > > > > > advance, and hope that their burned coins > > > > > > > > > > > > > > > > > got rewarded in some far > > > > > > > > > > > > > > > > > future > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > - the point of burned coins is to mimic, in > > > > > > > > > > > > > > > > > every meaningful way, the > > > > > > > > > > > > > > > > > value gained from proof of work... > > > > > > > > > > > > > > > > > without some of the security > > > > > > > > > > > > > > > > > drawbacks > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > - the miner risks losing all of his burned > > > > > > > > > > > > > > > > > coins (like all miners risk > > > > > > > > > > > > > > > > > losing their work in each block) > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > - new burns can't be used > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > - old burns age out (like ASICs do) > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > - other requirements on burns might be > > > > > > > > > > > > > > > > > needed to properly mirror the > > > > > > > > > > > > > > > > > properties of PoW and the incentives > > > > > > > > > > > > > > > > > Bitcoin uses to mine honestly. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 3. i do believe it is possible that a > > > > > > > > > > > > > > > > > "burned coin + vdf system" > > > > > > > > > > > > > > > > > might be more secure in the long run, and > > > > > > > > > > > > > > > > > that if the entire space > > > > > > > > > > > > > > > > > agreed that such an endeavor was > > > > > > > > > > > > > > > > > worthwhile, a test net could be spun > > > > > > > > > > > > > > > > > up, and a hard-fork could be initiated. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 4. i would never suggest such a thing unless > > > > > > > > > > > > > > > > > i believed it was > > > > > > > > > > > > > > > > > possible that consensus was possible. so > > > > > > > > > > > > > > > > > no, this is not an "alt > > > > > > > > > > > > > > > > > coin" > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Tue, May 18, 2021 at 10:02 AM Zac > > > > > > > > > > > > > > > > > Greenwood [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Hi ZmnSCPxj, > > > > > > > > > > > > > > > > > > Please note that I am not suggesting VDFs > > > > > > > > > > > > > > > > > > as a means to save energy, but solely as a > > > > > > > > > > > > > > > > > > means to make the time between blocks more > > > > > > > > > > > > > > > > > > constant. > > > > > > > > > > > > > > > > > > Zac > > > > > > > > > > > > > > > > > > On Tue, 18 May 2021 at 12:42, ZmnSCPxj > > > > > > > > > > > > > > > > > > [email protected] wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Good morning Zac, > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > VDFs might enable more constant block > > > > > > > > > > > > > > > > > > > > times, for instance by having a > > > > > > > > > > > > > > > > > > > > two-step PoW: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 1. Use a VDF that takes say 9 minutes > > > > > > > > > > > > > > > > > > > > to resolve (VDF being subject to > > > > > > > > > > > > > > > > > > > > difficulty adjustments similar to the > > > > > > > > > > > > > > > > > > > > as-is). As per the property of VDFs, > > > > > > > > > > > > > > > > > > > > miners are able show proof of work. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 2. Use current PoW mechanism with > > > > > > > > > > > > > > > > > > > > lower difficulty so finding a block > > > > > > > > > > > > > > > > > > > > takes 1 minute on average, again > > > > > > > > > > > > > > > > > > > > subject to as-is difficulty adjustments. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > As a result, variation in block times > > > > > > > > > > > > > > > > > > > > will be greatly reduced. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > As I understand it, another weakness of > > > > > > > > > > > > > > > > > > > VDFs is that they are not inherently > > > > > > > > > > > > > > > > > > > progress-free (their sequential nature > > > > > > > > > > > > > > > > > > > prevents that; they are inherently > > > > > > > > > > > > > > > > > > > progress-requiring). > > > > > > > > > > > > > > > > > > > Thus, a miner which focuses on improving > > > > > > > > > > > > > > > > > > > the amount of energy that it can pump > > > > > > > > > > > > > > > > > > > into the VDF circuitry (by overclocking > > > > > > > > > > > > > > > > > > > and freezing the circuitry), could > > > > > > > > > > > > > > > > > > > potentially get into a winner-takes-all > > > > > > > > > > > > > > > > > > > situation, possibly leading to even worse > > > > > > > > > > > > > > > > > > > competition and even more energy > > > > > > > > > > > > > > > > > > > consumption. > > > > > > > > > > > > > > > > > > > After all, if you can start mining 0.1s > > > > > > > > > > > > > > > > > > > faster than the competition, that is a > > > > > > > > > > > > > > > > > > > 0.1s advantage where only you can mine in > > > > > > > > > > > > > > > > > > > the entire world. > > > > > > > > > > > > > > > > > > > Regards, > > > > > > > > > > > > > > > > > > > ZmnSCPxj > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > bitcoin-dev mailing list > > > > > > > > > > > > > > > > > [email protected] > > > > > > > > > > > > > > > > > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > > > > > > > Michael Dubrovsky > > > > > > > > > > > > > > > > Founder; PoWx > > > > > > > > > > > > > > > > www.PoWx.org > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > > > > > > Michael Dubrovsky > > > > > > > > > > > > > > > Founder; PoWx > > > > > > > > > > > > > > > www.PoWx.org > > > > > > > > > > > > > > > bitcoin-dev mailing list > > > > > > > > > > > > > > > [email protected] > > > > > > > > > > > > > > > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > > > > > > > > > > > > > > > > > > > > > > > > > > > bitcoin-dev mailing list > > > > > > > > > > > > > > [email protected] > > > > > > > > > > > > > > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > > > > > > > > > > > > > > > > > > > > > > > > > bitcoin-dev mailing list > > > > > > > > > > > > > [email protected] > > > > > > > > > > > > > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev _______________________________________________ bitcoin-dev mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
