Almost everything in blockchain development rests on a handful of core ideas. A blockchain is a shared record of transactions that many computers keep in sync, with no single party in charge of it. Before writing any contract or touching any wallet, it helps to know exactly what that record is made of and why people trust it.
You'll start with what a blockchain is and the problem it was built to solve, then look at how blocks are chained together using hashes. From there the module covers the distributed ledger: how a network of independent nodes holds identical copies of the data, and what immutability really means in practice. It closes with the difference between public and private chains and where blockchains are used beyond cryptocurrency.
With the big picture in place, you'll be ready for the next module, Cryptography Essentials, which digs into the hashing and signatures that make this design secure.
A plain-language introduction to blockchain: what it is, the problem it solves, and why a shared record without a central owner is useful.
What is inside a block, how each block stores the hash of the one before it, and why that chain makes old data very hard to change.
How a peer-to-peer network of nodes keeps identical copies of the ledger, and what decentralization means compared with a traditional database.
Where blockchains are used beyond cryptocurrency, from healthcare and voting to digital identity and supply chains.