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The key aspect of a blockchain is that each block contains the hash of the previous block. That provides integrity guarantees that you don't get simply by using

• vurpo 5y ago
  That part is very easy to implement without all the extra cruft that a blockchain also brings with it. Git manages to do that same thing without burning a ton of coal every time you make a commit.
• xg15 5y ago
  I'd say the "each block contains the hash of a previous block" property is the implementation but not the key aspect. (Unless you count a git repo as a blockchain too) I think the key aspect is that it is a database that no single person or organisation can delete or alter - not even the developers or operators of the database themselves. The only operation possible is append. But this property requires that the majority of nodes participating in the chain are not under your control. When the nodes are under your control, you could just order them to swap out the current chain with one you just made up. (Which is effectively how git's "history rewriting" features work) This doesn't provide any more integrity than an ordinary database. On the other hand, if you want an append-only database and you already have a central gatekeeper that you trust (as required for access enforcement), you also can use an ordinary database and have the gatekeeper enforce the append-only property. No blockchain required.