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> payment channels (yawn) Don't you find 2nd layers like Lightning interesting, as a way to scale far beyond the limited L1 capacity? > Do you have a citation

by tromp 3y ago

> payment channels (yawn) Don't you find 2nd layers like Lightning interesting, as a way to scale far beyond the limited L1 capacity? > Do you have a citation for a block-based relative timelock? See the thread starting with https://lists.launchpad.net/mimblewimble/msg00546.html https://lists.launchpad.net/mimblewimble/msg00546.html > What about absolute lock times? Those are trivially supported in any Mimblewimble chain.

adastra22 3y ago
Not really, no. Lightning is still payments, multi-party and multi-hop. If the entire realm of Blockchain and smart contract technology was restricted to just payments, well I suppose that would be something. But far short of the total revolution of societal structure that was promised. I personally wouldn’t care to work on it if that was the case. Lightning is an implementation of distributed payments. Smart contracts are an implementation of decentralized law. Your link to the mailing list thread describes essentially the same approach that bitcoin has for dealing with lock times. I would not normally describe this as “scriptless scripts,” which I have understood to me using the signing operation itself to achieve some goal that would otherwise be done in script. The locktime here is still enforced by special cased code of the consensus algorithm. If the number of things you want to do are fixed and enumerable then I suppose this is a valid approach. But it does not allow for general, arbitrary, future-defined constraints. To give a concrete, simple example: show me how to do a return peg validation on scriptless scripts. If it can’t even do that, it is not a replacement for scripts.
- tromp 3y ago
  > far short of the total revolution of societal structure that was promised. Satoshi promised no such thing. That sounds more like an Ethereum promise (to which I don't subscribe). > show me how to do a return peg validation on scriptless scripts How does one do return peg validation in bitcoin script?
  - adastra22 3y ago
    The manual way. Validate SPV inclusion proofs using CAT, hash opcodes, bignum addition, etc. To be practical it requires block header commitments, but there are other reasons for wanting that. You also need relative locktime, which original bitcoin did not have. But that should be all that is required to be added. Other commonly cited things like Merkle branch verification opcodes just make the script more compact, or get around the fact that some required opcodes were later disabled and/or restricted from use with bignums. Re: bitcoin vs. ethereum, the bitcoin community pre-ethereum was very invested in the idea of decentralizing all the things. I remember: I was there and part of that history. But over time people interested in more than just payments or the bitcoin asset have left or switched to ethereum. Originally expressive smart contracting was very much in scope.
    - tromp 3y ago
      > But that should be all that is required to be added. If you're talking about SPV inclusion on another chain, wouldn't one also need to verify cumulative diff on that other chain (if PoW based) ?
      - adastra22 3y ago
        You can add and compare bignums in bitcoin script.
        tromp 3y ago
        Verifying cumulative diff requires verifying possibly thousands of headers (all those between peg out and peg in), which is a completely impractical amount of witness data for one script.
        adastra22 3y ago
        Committing headers in Merkle tree form or skip lists allow for logarithmic reduction in that number, as was worked out in the (2014?) sidechains whitepaper. 10’s of headers would be doable.

by tromp 3y ago

adastra22 3y ago

Not really, no. Lightning is still payments, multi-party and multi-hop. If the entire realm of Blockchain and smart contract technology was restricted to just payments, well I suppose that would be something. But far short of the total revolution of societal structure that was promised. I personally wouldn’t care to work on it if that was the case. Lightning is an implementation of distributed payments. Smart contracts are an implementation of decentralized law. Your link to the mailing list thread describes essentially the same approach that bitcoin has for dealing with lock times. I would not normally describe this as “scriptless scripts,” which I have understood to me using the signing operation itself to achieve some goal that would otherwise be done in script. The locktime here is still enforced by special cased code of the consensus algorithm. If the number of things you want to do are fixed and enumerable then I suppose this is a valid approach. But it does not allow for general, arbitrary, future-defined constraints. To give a concrete, simple example: show me how to do a return peg validation on scriptless scripts. If it can’t even do that, it is not a replacement for scripts.

tromp 3y ago
> far short of the total revolution of societal structure that was promised. Satoshi promised no such thing. That sounds more like an Ethereum promise (to which I don't subscribe). > show me how to do a return peg validation on scriptless scripts How does one do return peg validation in bitcoin script?
- adastra22 3y ago
  The manual way. Validate SPV inclusion proofs using CAT, hash opcodes, bignum addition, etc. To be practical it requires block header commitments, but there are other reasons for wanting that. You also need relative locktime, which original bitcoin did not have. But that should be all that is required to be added. Other commonly cited things like Merkle branch verification opcodes just make the script more compact, or get around the fact that some required opcodes were later disabled and/or restricted from use with bignums. Re: bitcoin vs. ethereum, the bitcoin community pre-ethereum was very invested in the idea of decentralizing all the things. I remember: I was there and part of that history. But over time people interested in more than just payments or the bitcoin asset have left or switched to ethereum. Originally expressive smart contracting was very much in scope.
  - tromp 3y ago
    > But that should be all that is required to be added. If you're talking about SPV inclusion on another chain, wouldn't one also need to verify cumulative diff on that other chain (if PoW based) ?
    - adastra22 3y ago
      You can add and compare bignums in bitcoin script.
      - tromp 3y ago
        Verifying cumulative diff requires verifying possibly thousands of headers (all those between peg out and peg in), which is a completely impractical amount of witness data for one script.
        adastra22 3y ago
        Committing headers in Merkle tree form or skip lists allow for logarithmic reduction in that number, as was worked out in the (2014?) sidechains whitepaper. 10’s of headers would be doable.