[HN Gopher] Ouroboros: A Provably Secure Proof-of-Stake Blockcha...
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       Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol
       [pdf] (2019)
        
       Author : dgellow
       Score  : 50 points
       Date   : 2021-01-31 18:50 UTC (4 hours ago)
        
 (HTM) web link (eprint.iacr.org)
 (TXT) w3m dump (eprint.iacr.org)
        
       | JohnJamesRambo wrote:
       | How does this compare to the current implementation of proof of
       | stake in Ethereum 2.0?
        
         | gvhst wrote:
         | They claim (via formal verification, I cannot speak to their
         | threat model with much accuracy) that they are able to achieve
         | the same or better security properties as ETH 2.0 without
         | lockups (staked funds earning income are like demand deposits)
         | or slashing (penalties for bad behavior / bad network
         | performance).
         | 
         | The project as a whole (Cardano) has some other notable
         | advantages. Personally, it has a built in governance system
         | which actively funds projects / improvement proposals paid for
         | by some of the block rewards & fees. Cardano just had their
         | first round of voting and funding which gave in aggregate $250k
         | to a variety of projects [0]. Funding batch sizes are expected
         | to grow to $10 million dollars a year in 2021 (at current
         | prices). This is where I'd draw the largest difference between
         | ETH 2.0 and Cardano (the project which developed and uses
         | Ouroboros)
         | 
         | [0] https://iohk.io/en/blog/posts/2021/01/12/project-catalyst-
         | th...
        
       | dgellow wrote:
       | You may also want to see this video from 2018 where the paper is
       | presented by Christian Badertscher:
       | https://www.youtube.com/watch?v=TCA0h73q3qQ&list=PLnPTB0CuBO...
        
         | Mindless2112 wrote:
         | Unfortunately, the introduction of the presentation took too
         | much time, so the novel part of the presentation is very hand-
         | wavy.
        
       | ypeterholmes wrote:
       | Important paper here because almost all the next gen blockchains
       | will be using POS. Ethereum is trying to switch mid-flight
       | (yikes) but others like Cardano have incorporated it
       | foundationally.
       | 
       | If you're a no-coiner or Bitcoin maximalist, none of this really
       | matters. But if you accept the premise that the future of
       | financial infrastructure is moving towards decentralized,
       | blockchain based systems, then a secure, scalable, performant,
       | and energy efficient approach like this is pretty darn awesome.
        
       | nikdot wrote:
       | craig wright is NOT satoshi nakamoto
        
       | poisonborz wrote:
       | I have the tingling feeling that one could think of a better name
       | for a blockchain protocol.
        
         | wmf wrote:
         | It's a great name because PoS doesn't require using outside
         | resources (e.g. energy). Once the system gets going it secures
         | itself.
        
       | martindale wrote:
       | Proof of Stake not only replicates the same dynamics that Bitcoin
       | was designed to eliminate (more wealth -> more power in system)
       | but also can only be made secure against a maximum of  1/3
       | byzantine actors, compared to Proof of Work's superior 1/2.
       | 
       | As for using it for Layer 1 systems, Andrew Poelstra nailed it in
       | his conclusion [0]:
       | 
       | "We showed that by depending only on resources within the system,
       | proof of stake cannot be used to form a distributed consensus,
       | since it depends on the very history it is trying to form to
       | enforce loss of value."
       | 
       | Proof of Stake might be useful at Layer 2 (becoming equivalent to
       | voting stock in a company), but not as a base-layer consensus
       | mechanism.
       | 
       | [0]: https://download.wpsoftware.net/bitcoin/pos.pdf
        
         | dgellow wrote:
         | The Ouroboros paper seems to say that it is 50% resistant. See
         | the parts highlighted here and the additional comments in this
         | forum thread: https://forum.cardano.org/t/is-cardano-51-attack-
         | resistant/1....
        
         | RhodoGSA wrote:
         | Check out Polkadot - They NPOS system works and not how you
         | described.
        
           | dane-pgp wrote:
           | I wasn't familiar with Polkadot, but this documentation page
           | seems to be a good introduction to how its "Nominated Proof-
           | of-Stake" system works:
           | 
           | https://wiki.polkadot.network/docs/en/learn-staking
        
         | wmf wrote:
         | It's true that PoS requires subjectivity to prevent long-range
         | attacks, but everyone is already using subjectivity so this is
         | not an additional constraint. (People say that, in theory, new
         | users _might_ not use subjectivity in PoW but this is not
         | actually true in practice.)
        
         | dane-pgp wrote:
         | > only be made secure against a maximum of  1/3  byzantine
         | actors
         | 
         | What is the threat model here, and in particular what is the
         | outcome of a successful attack?
         | 
         | For example, if the only "power in the system" the attacker has
         | is the ability to prevent transactions from occurring, then the
         | attacker is damaging the value of their own coins. The honest
         | majority could, as a last resort, also decide to manually fork
         | the currency to invalidate the attacker's coins.
         | 
         | Assuming the  1/3  number is weighted by stake, the attacker is
         | potentially risking billions of dollars in order to carry out
         | this short-term attack. With that amount of money it would be
         | cheaper to locate and destroy the major bitcoin mining farms.
        
           | wmf wrote:
           | There are concerns (or concern trolls) about an attacker
           | buying old keys for almost nothing, trashing the chain, then
           | profiting by shorting. And there are concerns that the honest
           | majority can't figure out how to switch to the honest fork.
        
             | regisg wrote:
             | That's why there are KES keys.
        
         | gvhst wrote:
         | Not sure if you are claiming that BTC currently solves the
         | "more wealth -> more power in system" problem but it clearly
         | doesn't. The current state of affairs is more wealth -> more
         | ASICS R&D and infrastructure budget -> more hash power -> more
         | power in the system.
        
           | splintercell wrote:
           | Matthew principle strikes again.
        
           | Geee wrote:
           | There's a difference. You can't physically centralize energy
           | production. Local energy price will increase when more energy
           | is used. This ensures that no one can get in a position of
           | control. In PoS, it's possible to get > 50% ownership, and
           | it's game over.
        
             | wmf wrote:
             | Is 70% of Bitcoin mining still in China?
        
             | sp821543 wrote:
             | Aren't 65% of all bitcoin miners in China? Couldn't the CCP
             | sabotage the network at any time? Say, a month before the
             | launch of their digital currency?
             | 
             | https://cbeci.org/mining_map
        
         | martin1975 wrote:
         | was this submitted to any crypto journals for peer review (CCS,
         | Eurocrypt) or did the author arrive at this conclusion in
         | isolation?
        
           | regisg wrote:
           | Ouroboros Genesis ? Yes : CCS 2018.
        
       | fsociety wrote:
       | Admittedly I skimmed the paper but didn't see any comparison with
       | state of the art. How does this differ from Tezos'
       | implementation?
        
         | jki275 wrote:
         | https://arxiv.org/pdf/2001.07091.pdf
         | 
         | Pgs 19 and 20.
        
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       (page generated 2021-01-31 23:01 UTC)