Beginner
Free
4 modules · 10 lessons
Blockchain Fundamentals
Transactions, Merkle trees and consensus — how a blockchain actually reaches agreement and stays honest.
What you will learn
- Describe the parts of a block and how chains are linked
- Follow a transaction from signing to confirmation
- Explain why tampering with history is detectable and expensive
- Compare Proof of Work and Proof of Stake honestly
- Recognise the real attack surface of blockchain systems
Prerequisites
- recommended Understanding Cryptography
About this course
This course follows a single transaction from your wallet all the way into a confirmed block, then zooms out to the mechanisms that keep the whole chain honest: Merkle trees, mining, staking and the economics around them.
Every lesson pairs a plain-English explanation with a hand-drawn figure, a real-world example and a lab you can break on purpose.
Curriculum
Blocks and the ledger 3 lessons
- What is a blockchain? Lesson · 12 min
- Blocks and chains Lesson · 14 min
- Why blockchains are hard to change Lesson · 12 min
Transactions 2 lessons
- Transactions Lesson · 15 min
- Merkle trees Lesson · 14 min
Consensus 3 lessons
- Proof of Work Lesson · 15 min
- Proof of Stake Lesson · 13 min
- Comparing consensus mechanisms Lesson · 10 min
Keys & real-world limits 2 lessons
- Wallets and keys Lesson · 12 min
- Attacks and limits Lesson · 14 min