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B: We’re almost there! There are two important things to know about blockchain: first, you can’t actually edit a blockchain – you can only add to it.
A: Isn’t adding to a blockchain editing it?
B: … well, OK, yes. What I meant to say is you can’t edit something that has already been added to the blockchain. You can only add new things to the blockchain.
A: Wait. So what if the thing recorded in the blockchain is no longer true? Like, the blockchain says I own a thing, and then I give you the thing?
B: Then we add a new entry to the blockchain saying “A gave B the thing.” When you go through the blockchain in chronological order, you’ll see that first you had the thing, then you gave it to me.
B: Second, there are two ways to store information in a blockchain, called “on-chain” and “off-chain.”
B: “On-chain” is when you load an entire thing on to a blockchain. Like a document, for example. “Off-chain” is when you load metadata describing a thing to the blockchain.
A: So where’s the joke?
B: No joke. Just blockchain stuff.
A: This is a webcomic. There has to be a joke.
B: I don’t know what to tell you. I don’t have a joke ready yet.
A: You have to think of something!
B: I could maybe spin this into how I have off-chain metadata of an IP address pointing to a remotely hosted joke but someone turned off the hosting server and the IP doesn’t resolve, but I’d hav eto finish explaining blockchain first.
A: That’s not funny.
B: I’D HAVE TO FINISH EXPLAINING BLOCKCHAIN FIRST.