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blockchain without cryptography is like writing a data structure without any motivation for its existence. i.e. why hashtables were created in the first place?
by knocte 9y ago
blockchain without cryptography is like writing a data structure without any motivation for its existence. i.e. why hashtables were created in the first place? To have indexing (faster access than simple array/lists). What would be the point of a blockchain without cryptography? You cannot call that blockchain IMO (otherwise, any chain of blocks would be a blockchain, for example: a file is a blockchain, right?).
- danieldk 9y agoblockchain without cryptography is like writing a data structure without any motivation for its existence Note that you said asymmetric cryptography and your parent said that asymmetric cryptography is not the basis of the block chain. And they would be right, at its core, the blockchain consists of blocks of transactions in a Merkle tree. The Merkle tree typically uses a cryptographically strong hash, otherwise it would be possible to modify the Merkle tree without anyone noticing. But a hash is not asymmetric cryptography. In many applications of the blockchain, asymmetric cryptography is used to sign transactions. But that is largely orthogonal to the blockchain as a data structure. The blockchain as a data structure has useful applications without transaction signing, etc. What makes the discussion clouded is that some people define 'block chain' as transaction blocks in a Merkle tree, while others also consider distributed consensus, etc. to be part of the block chain.
- garmaine 9y agoAlso there's no reason asymmetric crypto has to be used. You could use Lamport signatures, for example.
- sirclueless 9y agoI believe the comment you are responding is making a distinction between the public key cryptography used to authorize spending from a private wallet, and the act of including a cryptographic hash of the previous block in the current block creating a blockchain (which only requires a strong hash function, not asymmetric cryptography). Blockchains as defined this way have existed long before there was a proof-of-work based consensus protocol to make Bitcoin a reality. In their more general form they are called "Merkel trees". Filesystems aren't generally structured this way but, for example, git repositories are Merkel trees.
- garmaine 9y agoMerkle. They were invented by Ralph Merkle, not the chancellor of Germany. This would be a Merkel tree: http://c8.alamy.com/comp/D5AYH7/german-chancellor-angela-merkel-waters-a-tree-inastana-kazakhstan-D5AYH7.jpg http://c8.alamy.com/comp/D5AYH7/german-chancellor-angela-mer...
- zaarn 9y agoGit is an example of a blockchain without much cryptography, as someone else explained here. The only cryptography is the SHA1 hash that links commits together, otherwise all cryptography is optional. And that's totally okay because such repositories are usually run by people who have the authority over it. A blockchain is a special kind of linked graph that uses cryptography to link each node, otherwise, there are no additional requirements and there are plenty of reasons you might not want anything else.