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Blockchain: A Gallon of Milk Later

So we meet again, I think. If you are doing this correctly, you would have read my previous — hopefully not so boring — blogs on my learning journey through what blockchain is all about. I must say though, after re-reading my previous post and doing some freshly revised studies, my attempt at explaining blockchain was… rather incomplete. Quoting the famous meme: it needs some milk.

So here is another attempt, a gallon later, lol.


Deconstructing the Word

This time I’m going to break down the words, make sense of them individually, and then rebuild them with some more seasoning.

Blockchain.

“Block” + “Chain.”

Let’s start with  Block.

Googling the word, one of the definitions that pops up (which I picked for its convenience of the point I'm trying to make) is:

a large single building subdivided into separate rooms, flats, or offices.

And honestly, that’s not a terrible way to think about it.

I’ve also noticed something funny about the crypto ecosystem: most things are painfully literal:

  • Smart Contract is literally a contract that is smart.
  • Bitcoin is literally a coin in digital form.
  • Ethereum… yeah okay, that one didn’t get the memo.

This kind of mental mapping isn’t the full story, but it helps anchor the idea before we go swimming in the technical soup.


Building the Block

So let’s go back to the Block.

In crypto, a block really is a single building. But instead of rooms and offices, it contains things like:

  • Transactions
  • A block number
  • A cryptographic fingerprint (hash)
  • And sometimes a nonce
Bear with me. This sounds scary but it’s actually pretty neat. Let's start with the easiest one to grasp.


The Block Number. It’s literally just the building number on the street.

Block 1, Block 2, Block 3, and so on.

It tells everyone the order things happened in. And that's it.


Transactions, slightly less easy to understand, are the actual actions people take. From sending money, to swapping tokens, to interacting with a smart contract.

It's all essentially just data. And these data aka actions are then sent to a big public waiting room called the mempool

Not a pool for memes, but a memory pool where all the transactions are doing a public, highly competitive mating dance, in hope to be picked up by someone.

That someone is either:

  • a miner, in the case of in Bitcoin, or
  • a validator, when it come to Ethereum

Their job is to grab a bunch of these waiting transactions and bundle them together into a new building.


Moving on to The Hash (aka the fingerprint). This one is a big man thing kind of situation.

 It's what you get when you pass data through a one-way math function:

same input → same output.

change even one tiny thing → totally different output.

And you can’t go backwards.

It’s like turning a cow into a burger. Good luck trying to turn that burger back to a moo.

It's just not feasible, at least not yet.

Here’s the key idea:

All the transactions inside a block are cryptographically mashed together into one single fingerprint for the whole building. That fingerprint represents everything inside.

If anything changes — even one tiny transaction — the fingerprint changes too.


Now for the MVP, The Nonce. The meaning changes slightly differently depending on the Blockchain we are dealing with.

In Bitcoin, miners don’t just submit blocks. They have to win a lottery.

They take:

  • the block data
  • its fingerprint
  • and a random number called a nonce

Then they keep changing that nonce and re-hashing everything until the result matches a specific pattern (like starting with a certain number of zeros).

This isn’t clever problem-solving.

It’s brute-force dice-rolling at insane speed.

Whoever hits the winning number first gets to add the block and collect the Bitcoin reward.

Ethereum does this differently — instead of burning energy, validators lock up ETH as collateral and get chosen to propose and confirm blocks — but the goal is the same: someone earns the right to add the next building.


Making the Chain

Once a block is accepted, it gets added to the chain. And here’s where the magic really kicks in.

Every new block includes the fingerprint of the previous block inside it.

So Block 105 contains proof of Block 104.

Block 106 contains proof of 105. And so on.

If you try to change something in Block 100, its fingerprint changes — which breaks 101, which breaks 102, which breaks everything after it.

You don’t just have to fake one building. You have to rebuild the entire street faster than the rest of the world is adding new ones.

And because thousands of computers are watching and checking, the fake version gets rejected. Not instantly — but inevitably.

Again, there is way more to this but my brain is running low on ATP right now. 

Maybe I’ll dive into proof-of-work vs proof-of-stake another day, or maybe I will write about something completely useless and irrelevant, stick around to find out, or don't, I don't care. Okay I do, forgive me, don't leave me please. I love you.

For now, I’m going to marinate my head for a while.

Until next time,

s02minu🧊


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