Seed phrases and private keys: how to keep them safe
Your seed phrase is the master key to your crypto. Learn what it is, how to back it up offline and why you must never share it or type it online.
When you create a self-custody wallet, it shows you a list of 12 or 24 ordinary words. This is the seed phrase, also called a recovery phrase. It is the master backup of your wallet. From these words, the software can rebuild every private key and every address you will ever use in that wallet.
Seed phrase vs private key
A private key controls one address. The seed phrase is the root that generates all your private keys. Both must stay secret. If someone learns either one, they can move your coins without asking you.
Think of the seed phrase like the master key to an entire building, and a private key like the key to one room. Losing the master key is the worst case.
The three golden rules
- Never share it. No real company, support agent, exchange or wallet maker will ever ask for your seed phrase. Anyone who asks is trying to steal from you.
- Never type it into a website. Real wallets only ask for the phrase when you restore the wallet inside the app or on the hardware device itself. A web page asking you to "verify", "sync" or "validate" your wallet with your phrase is a phishing trap.
- Back it up offline. Write it on paper, or stamp it into a metal backup plate that survives fire and water. Do not save it in photos, notes apps, email, cloud drives or password managers that sync online.
Jonas gets a message: "Your wallet will be suspended in 24 hours. Click here and enter your 12 words to keep it active." The page looks exactly like his wallet's website. He remembers rule two: real wallets never ask for the phrase on a website. He closes the page. Had he typed the words, the attacker could have emptied his wallet within minutes.
Storing the backup
Store the backup somewhere private and safe from fire, floods and curious visitors. Some people keep two copies in two different places, such as home and a trusted relative's safe. Check that every word is spelled correctly and the order is right. One wrong word can make recovery fail.
Before you deposit real money, it is wise to practise a recovery. Create the wallet, write down the phrase, reset the wallet and restore it from your paper. If it works with an empty wallet, you know your backup is correct.
Screenshots are dangerous. Phones often upload photos to the cloud automatically. If that cloud account is ever hacked, your seed phrase goes with it.
What about the wallet password?
Many wallet apps also ask for a password or PIN. That only locks the app on that one device. It does not replace the seed phrase. If the phone breaks, the PIN is useless, and only the seed phrase can restore your funds.
A free account tracks lessons, unlocks the quizzes and gives you 10,000 virtual USD (no real value) to practise with.