Blockchain for Dummies
- mbegaia
- 12 de mar.
- 5 min de leitura
FPGAs ( Field-Programmable Gate Arrays, reprogrammable chips as one could think of) are today's flexible weapon in blockchain's tech arsenal — they help us push current systems to their limits, and get ready for the quantum world that might upend everything we know about cryptography.
Talk about Blockchain to a 5 year old...
Imagine you and your friends love to trade stickers. But sometimes, people forget who traded what or argue about it.
So, you all decide to keep a big notebook where every trade is written down. Every time someone trades a sticker, you write it in the notebook — like:
"Tom gave Anna 1 shiny sticker."
"Lucy gave Sam 2 dinosaur stickers."
Now, here's the fun part:
Everyone has a copy of this notebook!
If someone tries to lie and say, "Hey, Anna gave me 5 stickers!" everyone else can look in their notebooks and say, "Nope! That's not what we wrote down!"
Also, once you write something in the notebook, you can't erase it — so no cheating!
And every time the notebook page is full, you close that page and start a new one. All the pages are linked together like a chain — that's why it's called a blockchain (pages = blocks, linked together = chain).
The more "Grown-up" explanation of Blockchain
A blockchain is like a shared digital ledger (fancy word for a record book) that keeps track of transactions in a secure, transparent, and tamper-proof way.
It solves two big problems in digital transactions:
Who keeps the official records?
How do we make sure no one cheats or changes the records?
Here’s how it works, step by step:
Who writes in the "magic notebook"? (Who records transactions?)
Instead of one central authority (like a bank) keeping the records, a network of independent participants (nodes) all help verify and write the transactions.
In Bitcoin and most blockchains, these are called miners or validators, depending on the system.
They check if a transaction is valid before adding it to the blockchain.
Who can see the "notebook"? (Who has access to blockchain records?)
That depends on the type of blockchain:
Public blockchains (Bitcoin, Ethereum):
Everyone can see the transactions, just like if we made our sticker-trading notebook available online for all to read.
But no one can change the past records.
Private blockchains (Used by businesses, banks, etc.):
Only certain approved people can see and verify transactions.
Like a sticker-trading notebook that only some friends are allowed to check.
Where is the "notebook" kept? (Where is blockchain stored?)
Instead of one central storage (like a bank’s database), the blockchain is distributed across many computers worldwide.
Each computer (node) has a copy of the entire history of transactions.
So, if one copy gets lost or changed by a hacker, thousands of other copies exist to correct it—making it extremely difficult to alter.
What stops someone from cheating? (How does blockchain prevent fraud?)
Here’s the magic trick:
When you make a transaction, it doesn’t go directly into the notebook.
Instead, it first gets verified by many people (nodes/miners/validators).
Once they all agree it's valid, the transaction gets added to a block, which is locked and linked to the previous block.
This linking forms a chain of blocks—hence the name blockchain.
Because each block is linked to the previous one using cryptographic hashing, changing a past transaction would mean changing every block after it—which is practically impossible.
The Grown-Up Blockchain Summary (In One Paragraph)
A blockchain is a secure, decentralized, and tamper-proof digital ledger that records transactions across many computers. Transactions are verified by a network of participants (instead of a central authority) and stored in a way that makes them transparent, immutable (unchangeable), and fraud-resistant. Depending on the type of blockchain, it can be fully public (like Bitcoin) or restricted to select participants (like private enterprise blockchains).
So what is Mining ?
Going back to the blockchain notebook analogy :
Before a new trade (transaction) gets written down, someone has to check that it's fair and valid, and decide the order of all trades happening at that moment.
Mining is the process where people (called miners) do this work. But instead of checking sticker trades, they’re checking digital transactions like Bitcoin being sent from one person to another.
What does "mining" really involve?
Step-by-step real-life breakdown:
People send transactions (like "Alice sends Bob 1 Bitcoin").
These transactions are waiting in a queue (called the mempool).
Miners pick a batch of transactions and try to group them into a block — a new page in the blockchain notebook.
But — before the block is accepted, miners have to solve a difficult math puzzle to prove they worked hard on this (this is called Proof of Work or PoW — more on that later).
First miner to solve the puzzle gets to add the block to the blockchain and gets a reward (usually new Bitcoins + transaction fees).
Everyone else on the network checks and agrees that this block is valid — and then they all update their copy of the notebook.
But what is this "math puzzle"?
It's called hashing. Here's a simple way to think about it:
Imagine a slot machine — you need to pull the handle until you get a result like "0000abc..."
Miners use computers (or FPGAs, GPUs, ASICs) to guess numbers as fast as possible until they get a "winning" number that makes the block’s "hash" start with a certain number of zeros.
This "winning number" is called a nonce (number used once).
Finding it is hard, but verifying that it's correct is easy for everyone else!
So can anyone mine? I guess, but bringing it back to reality:
Factor | Early Days (2009-2012) | Today |
Who could mine? | Anyone with a regular home computer (CPU mining) | Mainly big companies with huge data centers |
Equipment needed? | Basic laptops, PCs | Specialized machines (ASIC miners) |
Electricity use? | Low | Very high — like running an entire factory |
Chances of earning reward? | Good, even for individuals | Almost impossible alone, unless part of a mining pool |
Cost of entry? | Very low | Very high (hardware + electricity) |
So technically, yes anyone can try, but in practice, you'd need:
Expensive mining hardware (ASICs — Application-Specific Integrated Circuits).
Access to cheap electricity (mining is energy-hungry).
Possibly join a mining pool (a group of miners working together to increase chances and share rewards).
Mining Pools — Practical Reality
Since solo mining is almost impossible to profit from today, mining pools were invented.
You join a pool with thousands of other miners.
Everyone shares computing power.
If someone in the pool solves the puzzle, the reward is shared among everyone based on how much they contributed.
Mining in the Real World
Mining is how transactions are verified and added to the blockchain.
Miners solve hard math puzzles to "win" the right to write the next block.
They get rewards for this (new Bitcoins + fees).
Today, mining is competitive and industrialized, often done in large data centers.
Individuals can still mine, but usually via mining pools to have a real chance at earning something.
Mining is like a race to solve a hard puzzle, and whoever solves it first gets to write the next page in the blockchain book and earn a prize.
But today, to win this race, you need super-fast and powerful machines, cheap electricity, and often a team (mining pool) to do this.
Have ever heard of Zero-Knowledge Proof?
Have a seat.
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