So why is the blockchain so revolutionary?
Start with “people can’t be trusted.” Assume you are completely paranoid —if-they-can-screw-me-over-they-will.” Imagine you are blindingly intelligent. Invent a data storage technology that’s invulnerable, like Achilles with a pair of steel boots. Call yourself Satoshi Nakamoto. Call your invention a blockchain.
So who is Satoshi Nakamoto?
Sorry. I cannot tell you that. If I did someone would kill me.
OK. That’s annoying. So what is a blockchain?
Let’s start with the fact that databases usually store data in blocks of data. They’ve done that since God was a boy. They wait until they have lots of records to write — a block full — then they write them all in one block. It is more efficient that way.
So what is the ‘chain’ part?
When you store records in a blockchain, it chains all the blocks together without you even having to ask.
So what? Why would I care?
You wouldn’t if you didn’t care about security. You see the blockchain chains the blocks together with a hash and that makes them secure.
I have no idea what a hash is. You lost me right there.
It’s mathematical. I will not give you the detail. You’ll come after me with a baseball bat if I introduce any more terms and start writing math formulae. Nevertheless, it is possible to take a big block of data and “hash it.” and it gives you an impossible-to-forge fingerprint of the data. Every time a new block is created, it is stored with the hash of the previous block. It means that the previous block is locked, kinda frozen in time and order.
OK, so a supremely boring mathematical fingerprint locks the order of the blocks. Why should I care?
It means that no-one can ever forge a block. The values are locked in an impenetrable steel vault that is every bit as strong as the boots Achilles should have worn if he was going to survive the Trojan War.
Wait a minute you’re talking about computer data. You can lose that. You can overwrite that. What makes blockchain data so invulnerable?
Well, I didn’t mention it before, but since you’ve asked the right question — it’s invulnerable because it is distributed. There isn’t just one copy of the blockchain there are hundreds of copies of it. There could be thousands. If you wanted to mess with the value of any record in a block of data, you would have to change all the copies. And even then you could only mess with the latest block. The rest of them are locked in solid steel by the hash value.
You’re kidding me. What kind of dumbass system has thousands of copies of the same data?
One that wants to ensure that the data is never abused.
But where do you keep these hundreds of thousands of dumbass blockchain copies?
On many different servers across the Internet and the world.
But which, out of all those, is the real blockchain?
They all are. They all have equal validity.
There is a massive advantage to this. If one of those servers disappears, it doesn’t matter. If all the servers in a whole country disappear, it doesn’t matter. The system is resilient to the failure of even hundreds of these blockchain servers.
OK, but hold on, who is paying for this vast array of servers? The government? Gimme a break?
No. Not the government.
Independent freedom-loving computer nerds. There’s a scheme to incentivize people to provide this computer resource, but actually, there are different schemes.
Damn it; now I’m going to have to talk about many other things,
… of shoes and ships and sealing wax, and cabbages and kings, and mining pools and forking chains, and whether pig have wings.
But maybe I should focus first on blockchain attacks.
I’ll leave all of that for some other blog post.
But you never explained why the blockchain is so revolutionary. It just seems complicated to me, that’s all.
OK, I’ll catch that question again next time. For now, remember that the blockchain consists of blocks chained together and distributed across many servers.