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Stage 1 — Basics : The fundamentals of blockchain and cryptocurrencies. No technical background required. If you can use a bank app, you're ready for this.
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The traditional financial system relies on intermediaries (banks, payment processors, governments) to validate and record transactions. This works, but it comes with real downsides: fees, delays, censorship, and billions of people without access to basic financial services.
The core question that led to blockchain: what if two people could exchange value directly, without needing to trust a third party?
A blockchain is a shared, append-only database maintained by thousands of computers (called nodes) around the world. Instead of one company owning the ledger, everyone has a copy and the rules of the system make it nearly impossible to cheat.
Think of it like a Google Doc that:
Each new batch of transactions is bundled into a block, cryptographically linked to the previous one, forming a chain. Alter one block, and you break the entire chain. That's where the tamper-resistance comes from.
Bitcoin was the first application of blockchain technology, created in 2008 by the pseudonymous Satoshi Nakamoto. It introduced a decentralized digital currency, one that could be sent peer-to-peer (P2P) without a bank in the middle.
Bitcoin has a fixed supply of 21 million coins, enforced by code. No central authority can print more. This scarcity is intentional, and it's one of the properties that makes people treat it as "digital gold."
If there's no central authority, how does everyone agree on what's true? Through a consensus mechanism.
Bitcoin uses Proof of Work (PoW): to add a new block, computers (miners) must solve a computationally hard puzzle. The first one to solve it gets to add the block and earns a reward. This makes cheating extremely expensive, you'd need more computing power than the rest of the network combined.
Ethereum (covered in Stage 2) uses Proof of Stake (PoS), which is more energy-efficient and increasingly the industry standard.