Module 1 of 6 · Foundations
Money, records and trust
Before any technology, a question: how do people who don't know each other agree on who owns what? This module looks at records, the people who keep them, and the problem every digital system has to solve.
Lessons in this module
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1.1 The double-spending problem
9 min · Beginner
Lesson 1.1: why digital value is easy to copy, why that matters, and how the double-spending problem shaped the design of blockchains.
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1.2 Ledgers through history
10 min · Beginner
Lesson 1.2: from clay tablets and double-entry bookkeeping to the stones of Yap — what a ledger is and why shared records are so old.
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1.3 Centralised and distributed systems
11 min · Beginner
Lesson 1.3: the difference between centralised, decentralised and distributed systems, and the Byzantine Generals problem in plain English.