What is a seed phrase?

A seed phrase is a numbered list of short, common English words, such as *ocean*, *ladder*, *cabin*, *rescue*. Your device shows them to you once, during setup, and asks you to write them down in order.

The words come from a fixed list of 2,048, published as part of a standard called BIP39 that almost every wallet uses. Each word on the list can be identified by its first four letters, which is why some metal backup plates only have room for four letters per word. The final word also works as a checksum: it lets a wallet spot most typing mistakes rather than silently opening the wrong wallet.

Behind the words is a very large random number, generated by your device. The words are simply a human-readable way of writing that number down, so a person can read and copy it without mistakes.

From that one number, the device works out a master key, and from the master key it works out every private key and address your wallet will ever use, for every coin and account. The same words always produce the same keys, on any device or wallet app that follows the same standard. That is what makes recovery possible.

Two things follow from this:

• Your crypto is not stored on your device. It is recorded on the blockchain. The device holds the keys that let you move it, and the seed phrase can recreate those keys. Lose the device and keep the phrase, and you have lost nothing but the device.
• One seed phrase covers everything in that wallet. You do not get a separate phrase for each coin or each account. Bitcoin, Ethereum and the rest on one device all come from the same words.

The PIN protects the device. The seed phrase *is* the wallet. That is why someone who steals your device usually cannot get in, but someone who sees your seed phrase can.

Most devices and wallet apps use 12 or 24 words, and a few offer 18. Both 12 and 24 are far beyond what anyone could guess: a 12-word phrase is one of roughly 340 trillion trillion trillion possibilities. A longer phrase adds a safety margin, not a practical difference for most people. What matters far more is how the phrase is stored.

Newer Trezor devices create a 20-word backup by default. It uses a different standard, called SLIP39, from a different word list. It does the same job, and several other wallet apps support it, but it is not interchangeable with a 12 or 24-word phrase. If yours has 20 words, that is expected.

Your device generates the seed phrase itself when you set it up. That is the only safe way to get one.

• Never accept a seed phrase you did not watch your own device create. A device that arrives with words already printed on a card, or "pre-set up" by a seller, is a scam: whoever wrote those words can empty the wallet whenever they like.
• Never use an online seed phrase generator for a wallet that will hold real money. Any words that have appeared on a website or a computer screen could have been recorded.
• Never make up your own words. People are poor at choosing randomly, and phrases chosen by people can be guessed.

If you hold crypto on an exchange such as Coinbase or Kraken, you do not have a seed phrase. The exchange holds the keys and you have an account, protected by a password and two-factor authentication. That is what "not your keys, not your coins" refers to.

You get a seed phrase when you move your crypto into a wallet you control. See How to move crypto from an exchange to a hardware wallet.

The short version is below. For paper versus metal, where to keep it and how many copies to make, see Seed phrase storage: where should I keep mine?

• Only ever enter it on the device itself, and only to recover or check the wallet. Never type it into a phone, a computer, a website, an app, a password manager or an email.
• Never photograph it, scan it or store it in the cloud. Photos sync to the cloud automatically, and cloud accounts get hacked.
• Nobody legitimate will ever ask for it. Not Ledger, not Trezor, not your exchange, not "support", and not KeyCompass. Anyone who asks for it is trying to steal from you.
• Write it down clearly and in order, and keep the copy away from the device. Someone who finds both together has everything.
• Protect it from fire, flood and the people who share your home. Paper is fine to start with; stamped or engraved metal survives far more.
• Make sure the right person could find it, and know what it is for, if something happened to you.
• Check it. A backup with one wrong word can fail when you need it. See How to test your recovery phrase backup safely.

Some devices and wallet apps let you add a passphrase on top of the seed phrase, sometimes called a 25th word. The same seed phrase with a different passphrase opens a completely separate wallet. This protects you if someone finds your seed phrase: on its own, it opens only the wallet without the passphrase, which can be left empty or hold a small amount.

The catch is that the passphrase becomes a second thing you cannot lose. Forget it, or record it wrongly by a single character, and the wallet behind it is gone, even with the seed phrase in hand. It suits some people well, but it is worth understanding fully before you add one.

Almost every seed phrase scam tries to get you to type your words somewhere other than your device.

• Fake support. Someone replies to a post or messages you, claiming to be from a wallet maker or an exchange, and asks you to "verify", "sync" or "validate" your wallet. Real support never asks for your words and never contacts you first on social media.
• Fake apps and websites. Lookalike versions of wallet apps appear in search ads and app stores, and ask for your seed phrase to "restore" your wallet. Download wallet software only from the maker's own website, typed in yourself.
• Letters and emails claiming a security problem. Some are well printed and carry the right logo. Any message that ends with entering your words online is a scam.
• The "free seed phrase". Scammers post a seed phrase in public comments, posing as a beginner who cannot work out how to withdraw. The wallet holds money but cannot be emptied without a small fee, and anything you send to cover the fee is taken straight away. And a wallet that is not yours is not yours to empty, whatever the comment says.
• "Recovery services". Anyone offering to recover lost crypto in exchange for a fee up front, or for your seed phrase, is a scam.

Can someone guess my seed phrase? No. The number of possible phrases is so large that guessing one is not realistic with any computer that exists. Seed phrases are stolen, not guessed: through scams, photos, cloud backups and careless storage.

Does the order of the words matter? Yes. The same words in a different order make a different phrase, which is why your backup should be numbered.

Can I change my seed phrase? Not on an existing wallet. If you think your phrase has been seen by anyone, set up a new wallet with a new phrase, test the backup, and move your crypto across. Then treat the old phrase as compromised.

I've lost my seed phrase but still have the device. What now? Your crypto is safe for now, but the device is your only way in. Do not reset it. Set up a new wallet with a new phrase and move your funds across while the old device still works. See I've lost my recovery phrase. What now?

Can I use my seed phrase with a different device or app? Usually, yes, as long as both follow the same standard. Some wallet apps organise accounts slightly differently, so balances do not always appear straight away after a restore. Recover onto another hardware device, never into a phone or desktop app just to see if it works.

Is it safe to keep it in a password manager? It moves your seed phrase onto internet-connected devices, which is exactly what a hardware device exists to avoid. Keep it offline.

If you are about to create your first seed phrase, or want someone to check how you have stored an existing one, KeyCompass can go through it with you on a video call. You never show your words: everything stays on your own device and your own paper, and you finish with a clear, written plan.

KeyCompass never asks for your recovery phrase, a photo of it or any part of it. Anyone who does, whatever they claim to be, is attempting to steal from you.

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