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Blockchain fundamentals · Beginner · 8 h

How blockchains work

Hashing and hash-linked blocks, proof of work and proof of stake, keys, addresses, signatures and transactions, and the limits of what a chain guarantees.

Why employers care: Interviews for blockchain roles start with fundamentals. Developers who understand the mechanics make fewer expensive mistakes in contracts.

In the roadmaps for: Blockchain Developer

Lessons, in order

  1. Blocks, hashes and consensus in 40 linesBuild a tiny hash-linked chain with proof of work, watch it detect a rewritten block, and see why changing history is expensive.3 min
  2. Keys, addresses and signed messagesDerive an Ethereum address from a private key, sign a message, and see a changed message fail verification, using Foundry's cast.3 min