Blockchain: trust without intermediaries
In 2008, someone under the pseudonym Satoshi Nakamoto published nine pages that changed finance forever. The idea is simple: what if instead of a bank that keeps the books — mathematics? Instead of trusting an institution — trusting the code? This course explains how it works under the hood: from SHA-256 to smart contracts, from P2P networks to launching your own token.
What awaits you: 7 chapters, 41 lessons
Course structure
Tap a ring to learn about each chapter
Tap a ring to learn about each chapter
Try it now: the core magic of blockchain
Everything in blockchain rests on one idea: a hash function. Type any text — you get 64 hex characters. Change a single letter — the hash changes completely and unpredictably. That is the avalanche effect. That is why blockchains are hard to forge: change one block — its hash changes — the whole chain breaks.
Type any text — the hash updates instantly. Change one character to see the avalanche effect.
SHA-256 · 256 bits · 64 hex
Text to hash
SHA-256 (hex)
Web Crypto unavailable (use HTTPS or a modern browser)
15 years in six milestones: blockchain history
Tap an event — see the key idea ▶
2008–2009
Bitcoin
2013–2015
Ethereum
Smart contracts
2017
ICO boom
2020
DeFi
DeFi Summer
2021
NFTs
2022–2023
Ethereum PoS
The Merge
How a transaction reaches the blockchain
From pressing Send to inclusion in a block — several steps. Each step is guarded by cryptography you will study in this course.
Path from wallet to chain ▶
👛
Wallet
sign with private key
→
📡
Broadcast
P2P node network
→
📋
Mempool
waiting for miner/validator
→
⛏️
Miner / val.
PoW or PoS
→
📦
Block
included in the chain
→
✅
Confirmed
6 confirmations ≈ practical finality
What we cover in each chapter
Tap for chapter details
🔐
Ch.1: Cryptography
⛓️
Ch.2: Architecture
🗳️
Ch.3: Consensus
💎
Ch.4: Ethereum & EVM
📝
Ch.5: Solidity
🌐
Ch.6: Web3 + your token
Who this course is for
You don't need heavy math — we explain everything as we go. Basic JavaScript or Python helps for chapters 5–6, but isn't required from day one.
Tap a card — see what you'll get from the course
💻
Developer
🚀
Entrepreneur / product
🔍
Curious learner
📊
Investor / trader
ℹ️Blockchain is not only cryptocurrencies. Supply chains (Walmart + IBM Food Trust), voting pilots, health data, NFTs in games, DeFi with huge TVL. The technology solves one core problem: how many parties can trust a single source of truth without a central arbiter. That is what makes it revolutionary.