Blockchain, in plain English.

A blockchain is a list of records - usually transactions - kept on thousands of computers around the world at the same time. Each new record is added to the end and stamped with a code that depends on every record before it.

Because so many people hold a copy at once, you cannot quietly edit an old record without everyone's copy disagreeing. That's the trick that makes blockchains hard to fake. It replaces “trust the bank, the company, or the website” with “trust the math.”

A crypto coin or token is just an entry on the blockchain that says “this much of this thing belongs to that wallet.” That's the whole idea. The famous names you see online - Bitcoin, Ethereum, Solana - are different blockchains. $ASTROID is a token that lives on top of one of them (Solana).

The name and the picture you see are just a sticker. The real identifier is a long string of letters and numbers called a contract address. We come back to that in lesson 5 - it matters more than the sticker.

A crypto wallet doesn't hold your coins like a real wallet holds dollars. Your coins live on the blockchain. The wallet holds the key that proves the entries on the blockchain belong to you.

Lose the key and the coins are still on the blockchain - you just can't move them anymore. Hand the key to someone else and, from the blockchain's point of view, the coins now belong to them. The blockchain doesn't care whether the key was given, copied, stolen, or tricked out of you. It only looks at who has the key right now.

When a new wallet is created, the app shows 12 (sometimes 24) random words. These are called a seed phrase. They are not a password - they are the wallet itself, written in a form humans can copy by hand. Anyone who sees them can recreate the wallet on their own phone, instantly, anywhere in the world.

The single most important rule in crypto:

• Never type a seed phrase into a website. For any reason. Ever.
• Never send it in a chat, email, screenshot, or photo.
• No real support team, real app, or real wallet ever asks for it. If something asks, it is a scam. There is no exception.

Treat the seed phrase the same way an adult would treat the backup keys to a safe: written on paper, stored somewhere private, never photographed.

Anyone in the world can create a new coin in about thirty seconds. People who want to trick others do this constantly: they make a fake coin with the same picture and name as a popular one, and put it in front of you hoping you won't check.

The way to tell them apart is to find the contract address on the project's real website (for us, it's in the footer of every page) and compare it character-by-character to the one you're looking at. If even one letter is different, it is a different coin. The picture is irrelevant. The name is irrelevant. Only the address is real.

The same idea applies to websites. Read the address bar out loud, slowly. astrold.space and astroid.space look almost identical - but one of them isn't us.

DYOR stands for Do Your Own Research. You'll see it everywhere in crypto. It really just means: don't take a stranger's word for it; look it up yourself. The same skill works for any link, any news headline, any “limited-time offer.”

For a kid (or a careful grown-up), the three checks are:

1. ①Is the web address spelled right? Read it out loud, character by character. Most fakes are caught here.
2. ②Does the contract address match? Find the real one on the project's real website. Compare the first four and last four characters. If they don't match exactly, walk away.
3. ③Would a grown-up be fine with this? If the honest answer involves hiding it, lying about your age, or doing it before they get home - the answer is no. That's a friendship-with-yourself question. Be honest.