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Who signs the identity certificates? And who are "they" who maintain the repository? And who decides which commits are legitimate? Git is a distributed databas

by sowbug 8y ago

Who signs the identity certificates? And who are "they" who maintain the repository? And who decides which commits are legitimate? Git is a distributed database only if every copy eventually syncs to tip, and only if everyone can agree what "tip" is. Each of those conditions is hard to meet if the problem statement assumes that malicious actors have write access to the repo and can arbitrarily assert which fork is master.

rlpb 8y ago
You have exactly the same problem with "blockchain". Whatever solution you propose for this new blockchain can equally be applied to write a git merge driver for this new git repository. If your solution is "proof of work", then you have the additional problem that there is a large group of people with significant computational power who can take over your new blockchain for the appropriate fee.
- sowbug 8y ago
  When someone proposes a solution that involves throwing money at a problem, you should be jumping for joy, not asking what happens when someone then throws money at the problem. Such a solution is the economic equivalent of proving that an NP problem is actually a P problem. Blockchain as implemented in Bitcoin takes a thorny sociopolitical problem (how to store monetary value) and turns it into an economic problem (how to calculate SHA-256 moving the smallest number of electrons). As applied to the Rohingya situation, it switches out the political power of whoever is currently dominant and replaces it with monetary power (proof of work). It commoditizes political power. I don't know about you, but I'd take an economic problem of being the group with the most money (== computing power) over an intricate, shifting political problem any day of the week.
  - rlpb 8y ago
    > As applied to the Rohingya situation, it switches out the political power of whoever is currently dominant and replaces it with monetary power (proof of work). My assertion is that using a blockchain, as opposed to existing proven technologies, adds nothing of value. You keep restating the opposite claim, but you have yet to explain how a blockchain adds any value over not using one.
    - sowbug 8y ago
      You can facilitate git rewrites, but it's not computationally expensive (or expensive in any sense) to do that. So it's easy to erase history and start over. A proof-of-work approach (or proof-of-whatever, as long as the incentives are aligned) imposes a cost to rewriting history. And if you believe that there's some relationship between economic power and truth/goodness (debatable, but it's a tenet of most of Western societies), then creating a cost, even a wasteful one, is a good thing. If existing proven technologies have a way of making rewrites hard (not reputationally hard but economically hard), then I'd appreciate the education. I'm not aware of such a power.
      - rlpb 8y ago
        > A proof-of-work approach (or proof-of-whatever, as long as the incentives are aligned) imposes a cost to rewriting history. That's not exclusive to blockchains. Blockchains impose a cost to rewriting history because peers follow a set of rules that make it so. You can impose a similar set of rules in any alternative solution, blockchain or not. Simply do not accept non-fast-forward branch updates. Validate all proposed updates against your standard rules, and if validated, use your custom merge driver to implement any required merging rules. I have yet to see an description of a threat model here which explains how such a blockchain's decentralized consensus system solves this particular real world problem.
        sowbug 8y ago
        OK, now I think I see your point. Either you're agreeing that you could stick proof of work into a more conventional database (not sure if that's what you mean by "You can impose a similar set of rules in any alternative solution, blockchain or not"), or you don't think the self-validating nature of a proof-of-work blockchain is interesting. The alternative solution you describe in your first paragraph still has the flaw that a nation-state could delete all known copies of the real national database, publish a new one, and say "Here's the national git log. Oceania has always been at war with Eastasia." Someone finds a backup copy of the original and publishes it. Now, determining which one is right is basically a question of whoever shouts louder. There's nothing inherently better or worse about the fake log compared to the real one, since both follow the rules; it's a question of who you believe. In a blockchain solution, on the other hand, the nation-state would have to say "here's the real blockchain," but either the amount of work required to produce the fake one was more than the work required to produce the real one (in which case congratulations, they win), or else it's self-disproving. Nobody has to argue whether the real one's real, because the real one by definition has the most work put into it. Unless I'm misunderstanding you, your example alternative solution doesn't have that important feature. Myanmar obliterated all traces of the Rohingya, razing their villages, rebuilding entirely different structures on those locations, and then claiming that the Rohingya burned down their own homes and voluntarily left the country (listen to https://www.nytimes.com/2018/08/14/podcasts/the-daily/myanmar-rohingya-muslims-rakhine.html https://www.nytimes.com/2018/08/14/podcasts/the-daily/myanma... for more). It's completely within the threat model of this situation that a nation-state might want to rewrite its identity database and deny that it ever happened. Sorry if I'm still somehow talking past you.
  - Nerull 8y ago
    >When someone proposes a solution that involves throwing money at a problem, you should be jumping for joy I'm sure that people who are starving to death are grateful to know that a bunch of rich techbros are dumping money into an exercise in patting themselves on the back rather than spending it on anything actually useful. Your last paragraph is just hilariously naive.

by sowbug 8y ago

rlpb 8y ago

You have exactly the same problem with "blockchain". Whatever solution you propose for this new blockchain can equally be applied to write a git merge driver for this new git repository. If your solution is "proof of work", then you have the additional problem that there is a large group of people with significant computational power who can take over your new blockchain for the appropriate fee.

sowbug 8y ago
When someone proposes a solution that involves throwing money at a problem, you should be jumping for joy, not asking what happens when someone then throws money at the problem. Such a solution is the economic equivalent of proving that an NP problem is actually a P problem. Blockchain as implemented in Bitcoin takes a thorny sociopolitical problem (how to store monetary value) and turns it into an economic problem (how to calculate SHA-256 moving the smallest number of electrons). As applied to the Rohingya situation, it switches out the political power of whoever is currently dominant and replaces it with monetary power (proof of work). It commoditizes political power. I don't know about you, but I'd take an economic problem of being the group with the most money (== computing power) over an intricate, shifting political problem any day of the week.
- rlpb 8y ago
  > As applied to the Rohingya situation, it switches out the political power of whoever is currently dominant and replaces it with monetary power (proof of work). My assertion is that using a blockchain, as opposed to existing proven technologies, adds nothing of value. You keep restating the opposite claim, but you have yet to explain how a blockchain adds any value over not using one.
  - sowbug 8y ago
    You can facilitate git rewrites, but it's not computationally expensive (or expensive in any sense) to do that. So it's easy to erase history and start over. A proof-of-work approach (or proof-of-whatever, as long as the incentives are aligned) imposes a cost to rewriting history. And if you believe that there's some relationship between economic power and truth/goodness (debatable, but it's a tenet of most of Western societies), then creating a cost, even a wasteful one, is a good thing. If existing proven technologies have a way of making rewrites hard (not reputationally hard but economically hard), then I'd appreciate the education. I'm not aware of such a power.
    - rlpb 8y ago
      > A proof-of-work approach (or proof-of-whatever, as long as the incentives are aligned) imposes a cost to rewriting history. That's not exclusive to blockchains. Blockchains impose a cost to rewriting history because peers follow a set of rules that make it so. You can impose a similar set of rules in any alternative solution, blockchain or not. Simply do not accept non-fast-forward branch updates. Validate all proposed updates against your standard rules, and if validated, use your custom merge driver to implement any required merging rules. I have yet to see an description of a threat model here which explains how such a blockchain's decentralized consensus system solves this particular real world problem.
      - sowbug 8y ago
        OK, now I think I see your point. Either you're agreeing that you could stick proof of work into a more conventional database (not sure if that's what you mean by "You can impose a similar set of rules in any alternative solution, blockchain or not"), or you don't think the self-validating nature of a proof-of-work blockchain is interesting. The alternative solution you describe in your first paragraph still has the flaw that a nation-state could delete all known copies of the real national database, publish a new one, and say "Here's the national git log. Oceania has always been at war with Eastasia." Someone finds a backup copy of the original and publishes it. Now, determining which one is right is basically a question of whoever shouts louder. There's nothing inherently better or worse about the fake log compared to the real one, since both follow the rules; it's a question of who you believe. In a blockchain solution, on the other hand, the nation-state would have to say "here's the real blockchain," but either the amount of work required to produce the fake one was more than the work required to produce the real one (in which case congratulations, they win), or else it's self-disproving. Nobody has to argue whether the real one's real, because the real one by definition has the most work put into it. Unless I'm misunderstanding you, your example alternative solution doesn't have that important feature. Myanmar obliterated all traces of the Rohingya, razing their villages, rebuilding entirely different structures on those locations, and then claiming that the Rohingya burned down their own homes and voluntarily left the country (listen to https://www.nytimes.com/2018/08/14/podcasts/the-daily/myanmar-rohingya-muslims-rakhine.html https://www.nytimes.com/2018/08/14/podcasts/the-daily/myanma... for more). It's completely within the threat model of this situation that a nation-state might want to rewrite its identity database and deny that it ever happened. Sorry if I'm still somehow talking past you.
- Nerull 8y ago
  >When someone proposes a solution that involves throwing money at a problem, you should be jumping for joy I'm sure that people who are starving to death are grateful to know that a bunch of rich techbros are dumping money into an exercise in patting themselves on the back rather than spending it on anything actually useful. Your last paragraph is just hilariously naive.