Blockchain 101

Blockchain is a shared record of transactions. It is stored across many computers. It is designed to resist tampering.

What is a block?

• A batch of transactions.
• A timestamp.
• A link to the previous block.

What is a blockchain?

A chain of blocks, each referencing the one before it. This linking is what makes edits hard. If someone tries to rewrite history, the network rejects it.

Key Web3 ideas

• Public networks validate transactions.
• Wallets hold keys used to control assets.
• Smart contracts run rules on-chain.

Why it matters

You can move value and run apps without a central operator. That brings new options. It also brings new risks.

One question to test your understanding

If a block is changed, what else must change for the chain to stay valid?