The Seed Phrase

When you set up a self-custodial wallet for the first time, it gives you a list of words. Usually 12, sometimes 24. Completely random. Something like:

correct horse battery staple umbrella window coffee silver mountain bridge yellow lake

This is called a seed phrase, a recovery phrase, or a mnemonic. It is the master key to your wallet.

Everything your wallet can do — access your Bitcoin, sign transactions, prove ownership — can be reconstructed from those 12 words. On any device. On any compatible wallet app. Anywhere in the world. As long as you have those words in the right order, you have your Bitcoin.

This is both the power and the responsibility of self-custody.

If your phone is stolen, destroyed, or lost — you restore your wallet from the seed phrase and your Bitcoin is back. It was never really on the phone. It was always on the blockchain. The seed phrase just lets you access it.

If your seed phrase is found by someone else — they can access your Bitcoin just as easily as you can. No password needed. No identity check. Just the words.

This is why the Bitcoin community is almost obsessive about seed phrase security. Don’t store it digitally. Don’t photograph it. Don’t email it to yourself. Write it on paper, put it somewhere physically secure, and consider a second copy in a separate location.

Your seed phrase is not a password. It’s the key itself.

Tomorrow: how to set up your first mobile wallet — step by step.

— The Daily Bit