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> A distributed, append-only cryptographic ledger Pardon my ignorance, but isn’t that what a blockchain is?

by arkona 9y ago

CiPHPerCoder 9y ago
A distributed ledger doesn't necessarily mean a decentralized one. This is a handy reference to decide if you're building a cryptographic ledger or a blockchain: https://gist.github.com/joepie91/e49d2bdc9dfec4adc9da8a8434fd029b https://gist.github.com/joepie91/e49d2bdc9dfec4adc9da8a8434f...
- hiq 9y ago
  I think the confusion stems from permissioned vs permissionless blockchain, and the comment you replied assumed you were talking about one instead of the other. I find the plain term "blockchain" rather vague in that regard. In addition to this github gist, I like http://doyouneedablockchain.com/ http://doyouneedablockchain.com/ .
  - dsacco 9y ago
    For precision, it’s good to distinguish between decentralization and permissionlessness as separate axes. Technically speaking the two are commonly positively correlated, but you can build centralized, permissionless systems and decentralized, permissioned systems.
woah 9y ago
I agree that blockchain is overhyped right now, but I don't understand the common sentiment on HN that "you don't need a blockchain, just an append-only decentralized database with Merkel root logs", as if that's something easy to build. What is this hypothetical non-blockchain, where are you going to get it, and why not just use a blockchain if that's what you need?
- CiPHPerCoder 9y ago
  > I don't understand the common sentiment on HN that "you don't need a blockchain, just an append-only decentralized database with Merkel root logs", as if that's something easy to build. In my case, this sentiment accompanies an implementation in the form of an easily-deployable open source microservice. https://github.com/paragonie/chronicle https://github.com/paragonie/chronicle If it's too hard for people to build, they can use what I wrote. > What is this hypothetical non-blockchain, where are you going to get it, and why not just use a blockchain if that's what you need? That's the tx/s limit on Bitcoin today? I can do hundreds of writes per seconds to Chronicle on a modest VM without sweat. This is possible because it's centralized, albeit supports mirroring (i.e. replication) and cross-signing.
  - sharemywin 9y ago
    This sounds a lot like ripple: ... Are people still fighting about this or have they come to a consensus? I'm probably the worst person to represent whether there's a consensus or not since I'm one of the designers of Ripple. But the important thing, at least in my opinion, is that there is no "secret sauce". The software is open source. People are free to modify it however they please. We run the exact same software that we make available on our public servers and our validators. Others are free to run validators and they do so. As it happens, much of the network infrastructure is run by us today. But we are more than happy to turn that over to others who are willing to do it. Why do you care if something is decentralized? The main reason is usually that you don't want the users of the system to be forced to accept changes made by an owner/operator of the system whose interest may be averse to them. Ripple is decentralized in this sense. For example, eBay is not decentralized. They don't warehouse their goods. But if eBay the company says no auctions of adult merchandise, then there will be no such auctions. It wouldn't matter if every user disagreed with the policy. Their only recourse would be to re-create what eBay had done, that is, to themselves implement eBay's secret sauce. By contrast, Ripple has no secret sauce. Anyone can run their own servers. If we make changes people don't like, nothing requires them to run the code with those changes. If Ripple disappeared and users of the ledger wanted it to continue, nothing would stop them from continuing it. https://bitcoin.stackexchange.com/questions/40448/is-ripple-centralized-or-decentralized https://bitcoin.stackexchange.com/questions/40448/is-ripple-...
TheDong 9y ago
No, that's what a write-ahead-log is, or quite a few various databases, or a git branch are. The key innovation of the blockchain was the use of proof-of-work in order to associate an amount of computer-time with a given block, and then pick, from competing views of a blockchain, which view took the most energy to arrive at... all while being resistant to a small number of subversive actors. In short, the blockchain solved the Byzantine Generals’ Problem, and happened to use a append-only cryptographic ledger as part of it.
- Jasper_ 9y ago
  Proof of Work doesn't determine which view took the most energy to arrive at. What it does is give a self-adjusting brute force cracking problem that takes 10 real-world minutes to perform, regardless of the amount of energy put in. The assumption is that 10 minutes is enough for even the slowest links of the network to get an up-to-view of the world, preventing double-spends or similar issues.
- dozzie 9y ago
  > The key innovation of the blockchain was the use of proof-of-work in order to associate an amount of computer-time with a given block Correct. In other words, proof of work is only a tool to make everybody slow in producing data while keeping everybody fast in verifying it. > In short, the blockchain solved the Byzantine Generals’ Problem, No. It's a common misconception, but in fact it does not solve Byzantine generals problem, with the simplest reason being that the problem requires the solving protocol to terminate (blockchain does no such thing). > and happened to use a append-only cryptographic ledger as part of it. The correct terminology is not "ledger", but "document timestamping". You don't need to record transactions in blockchain, they can be any statements. Cryptographers already had such systems, except that each of those required trusted third party to produce timestamps.

> A distributed, append-only cryptographic ledger Pardon my ignorance, but isn’t that what a blockchain is?

by arkona 9y ago

> A distributed, append-only cryptographic ledger Pardon my ignorance, but isn’t that what a blockchain is?

A distributed ledger doesn't necessarily mean a decentralized one. This is a handy reference to decide if you're building a cryptographic ledger or a blockchain: https://gist.github.com/joepie91/e49d2bdc9dfec4adc9da8a8434fd029b https://gist.github.com/joepie91/e49d2bdc9dfec4adc9da8a8434f...

hiq 9y ago
I think the confusion stems from permissioned vs permissionless blockchain, and the comment you replied assumed you were talking about one instead of the other. I find the plain term "blockchain" rather vague in that regard. In addition to this github gist, I like http://doyouneedablockchain.com/ http://doyouneedablockchain.com/ .
- dsacco 9y ago
  For precision, it’s good to distinguish between decentralization and permissionlessness as separate axes. Technically speaking the two are commonly positively correlated, but you can build centralized, permissionless systems and decentralized, permissioned systems.

woah 9y ago

I agree that blockchain is overhyped right now, but I don't understand the common sentiment on HN that "you don't need a blockchain, just an append-only decentralized database with Merkel root logs", as if that's something easy to build. What is this hypothetical non-blockchain, where are you going to get it, and why not just use a blockchain if that's what you need?

CiPHPerCoder 9y ago
> I don't understand the common sentiment on HN that "you don't need a blockchain, just an append-only decentralized database with Merkel root logs", as if that's something easy to build. In my case, this sentiment accompanies an implementation in the form of an easily-deployable open source microservice. https://github.com/paragonie/chronicle https://github.com/paragonie/chronicle If it's too hard for people to build, they can use what I wrote. > What is this hypothetical non-blockchain, where are you going to get it, and why not just use a blockchain if that's what you need? That's the tx/s limit on Bitcoin today? I can do hundreds of writes per seconds to Chronicle on a modest VM without sweat. This is possible because it's centralized, albeit supports mirroring (i.e. replication) and cross-signing.
- sharemywin 9y ago
  This sounds a lot like ripple: ... Are people still fighting about this or have they come to a consensus? I'm probably the worst person to represent whether there's a consensus or not since I'm one of the designers of Ripple. But the important thing, at least in my opinion, is that there is no "secret sauce". The software is open source. People are free to modify it however they please. We run the exact same software that we make available on our public servers and our validators. Others are free to run validators and they do so. As it happens, much of the network infrastructure is run by us today. But we are more than happy to turn that over to others who are willing to do it. Why do you care if something is decentralized? The main reason is usually that you don't want the users of the system to be forced to accept changes made by an owner/operator of the system whose interest may be averse to them. Ripple is decentralized in this sense. For example, eBay is not decentralized. They don't warehouse their goods. But if eBay the company says no auctions of adult merchandise, then there will be no such auctions. It wouldn't matter if every user disagreed with the policy. Their only recourse would be to re-create what eBay had done, that is, to themselves implement eBay's secret sauce. By contrast, Ripple has no secret sauce. Anyone can run their own servers. If we make changes people don't like, nothing requires them to run the code with those changes. If Ripple disappeared and users of the ledger wanted it to continue, nothing would stop them from continuing it. https://bitcoin.stackexchange.com/questions/40448/is-ripple-centralized-or-decentralized https://bitcoin.stackexchange.com/questions/40448/is-ripple-...

TheDong 9y ago

No, that's what a write-ahead-log is, or quite a few various databases, or a git branch are. The key innovation of the blockchain was the use of proof-of-work in order to associate an amount of computer-time with a given block, and then pick, from competing views of a blockchain, which view took the most energy to arrive at... all while being resistant to a small number of subversive actors. In short, the blockchain solved the Byzantine Generals’ Problem, and happened to use a append-only cryptographic ledger as part of it.

Jasper_ 9y ago
Proof of Work doesn't determine which view took the most energy to arrive at. What it does is give a self-adjusting brute force cracking problem that takes 10 real-world minutes to perform, regardless of the amount of energy put in. The assumption is that 10 minutes is enough for even the slowest links of the network to get an up-to-view of the world, preventing double-spends or similar issues.
dozzie 9y ago
> The key innovation of the blockchain was the use of proof-of-work in order to associate an amount of computer-time with a given block Correct. In other words, proof of work is only a tool to make everybody slow in producing data while keeping everybody fast in verifying it. > In short, the blockchain solved the Byzantine Generals’ Problem, No. It's a common misconception, but in fact it does not solve Byzantine generals problem, with the simplest reason being that the problem requires the solving protocol to terminate (blockchain does no such thing). > and happened to use a append-only cryptographic ledger as part of it. The correct terminology is not "ledger", but "document timestamping". You don't need to record transactions in blockchain, they can be any statements. Cryptographers already had such systems, except that each of those required trusted third party to produce timestamps.