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what you're describing is a Merkle tree. Blockchains are essentially Merkle trees with a distributed consensus algorithm. Take away the consensus algorithm and

what you're describing is a Merkle tree. Blockchains are essentially Merkle trees with a distributed consensus algorithm. Take away the consensus algorithm and you're back to Merkle trees.

zellyn 8y ago
https://twitter.com/whitequark/status/946886702932557824 https://twitter.com/whitequark/status/946886702932557824 https://twitter.com/hikari_no_yume/status/933791331146784768 https://twitter.com/hikari_no_yume/status/933791331146784768 More seriously, some people apparently consider git a blockchain: https://medium.com/@shemnon/is-a-git-repository-a-blockchain-35cb1cd2c491 https://medium.com/@shemnon/is-a-git-repository-a-blockchain...
- deleted 8y ago
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- pdpi 8y ago
  Git histories absolutely are something in the blockchain family of data structures, yes, but they’re not a blockchain proper: the defining chacteristic of such data structures is that they use hashes instead of pointers as references to elements. Merkle trees and blockchains are analogous to trees and singly linked lists, respectively, while git histories are DAGs. Where things got murky was that the cryptocurrency crowd started to talk about the blockchain that backs Bitcoin in terms where the consensus layer was left implicit (our own Linux vs GNU/Linux story if you want to see it that way), then people less knowledgeable about cryptography started pouring in, they learned a bunch of new terminology, and along the way missed the nuance about the consensus layer being left implicit, so in their minds (and the world at large, eventually) blockchain means the combined data structure and consensus layer — It’s fairly obvious that git doesn’t meet the requirements for this definition of “blockchain”.
- greggyb 8y ago
  Git has a great proof-of-work and consensus mechanism in its original application. Proof-of-work is code that passes tests and consensus is "Linus said 'ok'".
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Faark 8y ago
Hm when I hear "tree", i'd expect it to be at least somewhat balanced. Wikipedia also has "Hash chain" and seems to be a better fit to me, but at that point we are basically arguing semantics. But yes, "blockchain" as used today is more than what we are talking about.
benchaney 8y ago
That is not what a merkle tree is. In a merkle tree, only the leaf nodes contain data (or hashes of data).

what you're describing is a Merkle tree. Blockchains are essentially Merkle trees with a distributed consensus algorithm. Take away the consensus algorithm and you're back to Merkle trees.

zellyn 8y ago

https://twitter.com/whitequark/status/946886702932557824 https://twitter.com/whitequark/status/946886702932557824 https://twitter.com/hikari_no_yume/status/933791331146784768 https://twitter.com/hikari_no_yume/status/933791331146784768 More seriously, some people apparently consider git a blockchain: https://medium.com/@shemnon/is-a-git-repository-a-blockchain-35cb1cd2c491 https://medium.com/@shemnon/is-a-git-repository-a-blockchain...

deleted 8y ago
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pdpi 8y ago
Git histories absolutely are something in the blockchain family of data structures, yes, but they’re not a blockchain proper: the defining chacteristic of such data structures is that they use hashes instead of pointers as references to elements. Merkle trees and blockchains are analogous to trees and singly linked lists, respectively, while git histories are DAGs. Where things got murky was that the cryptocurrency crowd started to talk about the blockchain that backs Bitcoin in terms where the consensus layer was left implicit (our own Linux vs GNU/Linux story if you want to see it that way), then people less knowledgeable about cryptography started pouring in, they learned a bunch of new terminology, and along the way missed the nuance about the consensus layer being left implicit, so in their minds (and the world at large, eventually) blockchain means the combined data structure and consensus layer — It’s fairly obvious that git doesn’t meet the requirements for this definition of “blockchain”.
greggyb 8y ago
Git has a great proof-of-work and consensus mechanism in its original application. Proof-of-work is code that passes tests and consensus is "Linus said 'ok'".

deleted 8y ago

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Faark 8y ago

Hm when I hear "tree", i'd expect it to be at least somewhat balanced. Wikipedia also has "Hash chain" and seems to be a better fit to me, but at that point we are basically arguing semantics. But yes, "blockchain" as used today is more than what we are talking about.

benchaney 8y ago

That is not what a merkle tree is. In a merkle tree, only the leaf nodes contain data (or hashes of data).