7 ms·

PoW is not needed at all its just a puzzle do "randomizes" who can write the next block. Its comically inefficient and p much the worst known working solution.

by noxer 4y ago

PoW is not needed at all its just a puzzle do "randomizes" who can write the next block. Its comically inefficient and p much the worst known working solution. Some BTC devs realized this and created Federated Byzantine Agreement (FBA) which used Byzantine Agreement rather than a puzzle to created the consensus and then federated the whole system to prevent 51%-like attacks. Obviously if the peers work together with the goal to reach consensus based on fix rules it becames way more efficient. Only a few year after bitcoin this was already invented theoretically and shortly after build an went online 2012/13. It essentially depreciated PoW (and Bitcoin) long before all the BTC clones existed and even before ETH. People just tend to stick to "the first of something" and fight whatever comes after. tl;dr The secret sauce of blockchain is not PoW, its a public state of a ledger that can be verified to be correct by anyone without trusting anyone simply by applying the rules of the system yourself.

MacsHeadroom 4y ago
PoW is needed for the "trustless" qualifier. Other schemes like PoS can be very low trust but not fully trustless. They also tend towards ever increasing centralization.
- noxer 4y ago
  No, its really not. It is literally just a puzzle which solves the "problem" as to who gets to write the next block. Instead if you define the rules for the next block as strict as possible so it essentially eliminates a huge variety of possible blocks, participants can instead easily agree on one (the best) block (one that follows all rules and is objectionably better than all other possible blocks). There is no need to "fight" over who can add that block, agreeing is way more efficient. And Consequentially the puzzle is no longer needed. PoS is not what I'm talking about at all. PoS just replaces the PoW puzzle with a "virtual puzzle" that acts as if higher stakes are higher hash power thus more chance to win the puzzle. Other than that its still the same "fight" over who gets to write the next block. PoW and PoS at scale leads to more centralization over time because of the economy of scale principle. While FBA (Federated Byzantine Agreement) leads to more decentralization because its in everyones interest to increase the number of participants, they are helping the system not competing.
  - Sammi 4y ago
    "agreeing is way more efficient" Then it's not trustless is it?
    - noxer 4y ago
      People mean different things with "trustless". Its trustless in the sense that you yourself can apply the rules and verify that each block follows the public rules. The "agreeing" is only within the rules and the rules are in the code. So you have to trust (or verify) that the code actually does implement the rules the way you want them to be.
  - FabHK 4y ago
    How do you solve double spend? So you make your objective rules as to what is the best block by defining some measure of quality (maybe include the most transactions that fit in, maybe sorted by fee-per-byte or so). Now all the good nodes agree on the next block B1 and then start working on B2 (not much work to do, because no PoW, but whatever, they build the next block B2.) Meanwhile, evil actor Eve has transferred a lot of money in B1 to Alice, and received something worthwhile. Now she makes an alternative block B1', transferring the money to her friend Bob instead of Alice, where B1' has even higher quality (higher fee, say), and quickly creates B2' and then B3'. How is a new node coming in to decide between the chain B1->B2, and the chain B1'->B2'->B3'? The latter chain is longer and has higher quality.
    - noxer 4y ago
      There is no block 2 created if block 1 is not final. Once consensus is reached on what is in B1 it doesn't matter anymore if someone comes around with a different idea what should be in B1. So by the time the nodes "debate" over B2, Alice has the money and its final. There can not be a double spend with time delay in between because the second transaction ties to move already moved funds so its objectively invalid. A double spend would need to happen in the same block but all transaction are ordered sequentially so the second one will fail anyway as it still tries to moved funds that are already moved. The nodes just have to agree on one, it doesn't matter which one. If someone internationally tries to send the same funds to Bob an Alice he's just flipping a coin as to who will get it. Alice doesn't care and Bob doesn't care either. They only care about it being final if they see the funds in their account. And the rest of the network doesn't care that Eve is being a bit silly and wants a "decentral coin flip" to decide where the money goes.

by noxer 4y ago

MacsHeadroom 4y ago

PoW is needed for the "trustless" qualifier. Other schemes like PoS can be very low trust but not fully trustless. They also tend towards ever increasing centralization.

noxer 4y ago
No, its really not. It is literally just a puzzle which solves the "problem" as to who gets to write the next block. Instead if you define the rules for the next block as strict as possible so it essentially eliminates a huge variety of possible blocks, participants can instead easily agree on one (the best) block (one that follows all rules and is objectionably better than all other possible blocks). There is no need to "fight" over who can add that block, agreeing is way more efficient. And Consequentially the puzzle is no longer needed. PoS is not what I'm talking about at all. PoS just replaces the PoW puzzle with a "virtual puzzle" that acts as if higher stakes are higher hash power thus more chance to win the puzzle. Other than that its still the same "fight" over who gets to write the next block. PoW and PoS at scale leads to more centralization over time because of the economy of scale principle. While FBA (Federated Byzantine Agreement) leads to more decentralization because its in everyones interest to increase the number of participants, they are helping the system not competing.
- Sammi 4y ago
  "agreeing is way more efficient" Then it's not trustless is it?
  - noxer 4y ago
    People mean different things with "trustless". Its trustless in the sense that you yourself can apply the rules and verify that each block follows the public rules. The "agreeing" is only within the rules and the rules are in the code. So you have to trust (or verify) that the code actually does implement the rules the way you want them to be.
- FabHK 4y ago
  How do you solve double spend? So you make your objective rules as to what is the best block by defining some measure of quality (maybe include the most transactions that fit in, maybe sorted by fee-per-byte or so). Now all the good nodes agree on the next block B1 and then start working on B2 (not much work to do, because no PoW, but whatever, they build the next block B2.) Meanwhile, evil actor Eve has transferred a lot of money in B1 to Alice, and received something worthwhile. Now she makes an alternative block B1', transferring the money to her friend Bob instead of Alice, where B1' has even higher quality (higher fee, say), and quickly creates B2' and then B3'. How is a new node coming in to decide between the chain B1->B2, and the chain B1'->B2'->B3'? The latter chain is longer and has higher quality.
  - noxer 4y ago
    There is no block 2 created if block 1 is not final. Once consensus is reached on what is in B1 it doesn't matter anymore if someone comes around with a different idea what should be in B1. So by the time the nodes "debate" over B2, Alice has the money and its final. There can not be a double spend with time delay in between because the second transaction ties to move already moved funds so its objectively invalid. A double spend would need to happen in the same block but all transaction are ordered sequentially so the second one will fail anyway as it still tries to moved funds that are already moved. The nodes just have to agree on one, it doesn't matter which one. If someone internationally tries to send the same funds to Bob an Alice he's just flipping a coin as to who will get it. Alice doesn't care and Bob doesn't care either. They only care about it being final if they see the funds in their account. And the rest of the network doesn't care that Eve is being a bit silly and wants a "decentral coin flip" to decide where the money goes.