Blockchain basics quiz

Digital data is easy to copy, so a system must stop the same value being used twice. Lesson 1.1.

One organisation keeps the authoritative copy and everyone trusts it. Lesson 1.3.

This "avalanche effect" is what makes hashes useful as fingerprints. Lesson 2.1.

The public key is used to check signatures; the private key must stay secret. Lesson 2.2.

Change one block and its hash changes, so the next block no longer points to it. Lesson 3.1.

Validators lock up a deposit that can be reduced if they break the rules. Lesson 3.3.

It is code, not a legal document, and runs exactly as written. Lesson 4.2.

Transactions consume earlier outputs and create new ones. Lesson 4.1.

Value is recorded on the blockchain; the wallet keeps the keys that can sign for it. Lesson 5.1.

No genuine service ever needs your recovery phrase. Lesson 5.3.

A central bank digital currency is issued by the central bank itself. Lesson 6.1.

Improving one of the three often costs something in another. Lesson 6.3.