What does NFT stand for?
AnswerNon-fungible token
Each NFT is a unique token, not interchangeable.
Tech · Facts & stats
Chain facts & stats
7 fact-checked facts about blockchains: how chained blocks, ledgers and smart contracts work, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
What must you keep secret to control a crypto wallet?
AnswerPrivate key
Anyone with the private key can move the wallet's funds.
Going deeper
How does each block link to the one before it?
AnswerIt includes the previous block's cryptographic hash
Changing an old block would break every later hash.
Which blockchain, launched in 2015, made smart contracts widely used?
AnswerEthereum
Ethereum runs programs called smart contracts.
On Ethereum, what are transaction fees commonly called?
AnswerGas
Gas measures the computing work a transaction needs.
Expert level
Which data structure, named after Ralph Merkle, summarizes all transactions in a block?
AnswerMerkle tree
A Merkle root lets anyone verify a transaction efficiently.
Stuart Haber and W. Scott Stornetta's 1991 work, a forerunner of blockchains, was about what?
AnswerTimestamping digital documents
Their chained timestamps are cited in the Bitcoin white paper.
Know these cold?Today's round is five questions like these, 20 seconds each. Your streak and level follow you to every arena.Play today's round