Introduction
You already know Bitcoin from afar. This module goes deeper: how thousands of computers secure the network with no central authority, why there will never be more than 21 million bitcoins, what the "halving" really is, and above all a widespread myth to correct: Bitcoin is NOT anonymous. It's a public ledger where every transaction is visible forever. Understanding this changes how you use it.
Proof of work: securing without a boss
Bitcoin has no central bank and no master server. To decide which transaction is valid without an authority, it uses proof of work. Specialized computers (miners) compete to solve an energy-costly puzzle. The winner proposes the next block of transactions and receives a reward in bitcoin. Cheating would require redoing that colossal work on more than half the network — economically absurd.
It's this real cost (electricity, hardware) that makes the ledger nearly impossible to falsify. Bitcoin's security isn't a promise: it's physics and economics.
The costly wax seal
Imagine that to validate a page of the ledger, you must melt a precise amount of rare wax and engrave a unique seal. Redoing every page to forge one would cost a fortune in wax. No one has an incentive to cheat: it's too expensive.
21 million and the halving
Bitcoin's code sets an absolute limit: there will never be more than 21 million bitcoins. The creation of new bitcoins (the miner reward) is halved roughly every four years: that's the "halving". At launch a block paid 50 BTC; after several halvings, far less. Around 2140, creation stops entirely.
This programmed scarcity is the core of Bitcoin's "store of value" thesis: unlike a currency a central bank can print without limit, Bitcoin's supply is mathematically bounded and predictable. Careful: scarcity guarantees no future price — it's a technical property, not a promise of gain.
- Absolute cap: 21 million BTC, written into the code.
- Halving ≈ every 4 years: the miner reward is cut in half.
- Predictable, decreasing issuance, until it stops around 2140.
Bitcoin's scarcity guarantees its price will rise.
Actually : No. Scarcity is a property of supply, not a guarantee of demand. Price depends on supply AND demand, and stays very volatile. No scarcity promises a return.
The UTXO model: Bitcoin doesn't keep a "balance"
Unlike a bank account showing a balance, Bitcoin works with unspent "coins" called UTXOs (Unspent Transaction Outputs). Your wallet adds up your UTXOs to show a total, but you actually hold a set of pieces received in past transactions. When you pay, your wallet combines UTXOs and gives you "change" as a new UTXO.
This technical detail directly affects privacy: each piece keeps a trace of its origin, making the history fully reconstructable.
A wallet of banknotes, not an account
You don't pay with a "balance": you pay with specific notes you received. If you owe €7 and have a €10 note, you hand it over and get €3 back. Bitcoin works the same — and every note can be traced.
Demonstration: Bitcoin is not anonymous
Here's the most dangerous myth: "Bitcoin is anonymous". Wrong. Bitcoin is PSEUDONYMOUS. Every transaction since 2009 is recorded in a public ledger anyone can inspect in real time via a block explorer. You don't see names there, but addresses (strings of characters). The day an address is linked to your identity — a KYC platform purchase, a public donation, a data leak — its entire history becomes associated with you.
Picture a concrete demonstration. You receive your salary in BTC on address A. You pay a merchant from that same address A. The merchant sees address A, and on the public explorer they see: how much you received, when, and all your other past and future spending from A. If you always reuse the same address, you literally publish your account statement to the whole world.
- The Bitcoin ledger is 100% public and viewable by anyone, forever.
- A reused address links all your transactions together.
- Linking an address to your identity (KYC, donation, leak) reveals its whole history.
- Best practice: don't reuse addresses; HD wallets generate a new one for each receipt.
Pseudonymous ≠ anonymous
Think of the ledger as a public noticeboard where each address is a pseudonym. As long as no one knows the pseudonym is you, you keep some privacy. But the board is permanent and public: the day the link is made, the whole history surfaces. Use a new address for each receipt (HD wallets do this automatically).
What this changes for you
Understanding proof of work helps you grasp why Bitcoin is so robust and hard to censor. Understanding the 21 million helps you tell the "store of value" thesis from mere hype. And understanding pseudonymity protects you from a common mistake: believing your BTC transactions are private.
On Deblock, you benefit from Bitcoin without managing UTXOs or addresses yourself day to day, but these notions stay essential to use Bitcoin in an informed, private way when you move to self-custody.
What you should remember
- 01Proof of work secures Bitcoin through a real cost (energy + hardware), with no central authority.
- 02Supply capped at 21 million; halving ≈ every 4 years; scarcity ≠ promise of price.
- 03Bitcoin works in UTXOs ("pieces"), not an account balance.
- 04Bitcoin is pseudonymous, not anonymous: the ledger is public and permanent.
- 05Don't reuse your addresses; HD wallets generate a new one for each receipt.
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