Seed phrase

By the Blockhorizon Editorial Team · Updated 2 October 2026 · How we check facts

What is a seed phrase used for?

Many wallets show you a list of words once, when you first set them up. That list is a human-readable backup. If your phone breaks or the wallet app is deleted, typing the same words into a compatible wallet rebuilds your keys and gives you access to the same funds.

This matters because a private key on its own cannot be regenerated: NIST says recreating the same key is computationally infeasible. The seed phrase is the backup that makes recovery possible at all.

How does restoring a wallet with a seed phrase work?

Picture losing your phone on a train. The crypto is not on the phone. It is recorded on the blockchain, and the phone only held the keys. On a new device, you install a wallet, choose the restore option and enter your words in the right order. The wallet derives the same keys, and your balance reappears.

The flip side is uncomfortable. A stranger who finds your written words can do exactly the same thing from their own device, and you will not be asked to approve it.

Where should you keep a seed phrase?

Offline, private and protected from loss or damage. The SEC warns that with self-custody a lost, stolen, damaged or hacked wallet can mean permanent loss of access, so the backup needs the same care as the original. Keep your holdings to yourself as well. The SEC lists that among its basic tips.

What are the most common seed phrase mistakes?

• Photographing the words or saving them in a notes app that syncs online.
• Typing them into a website that claims to verify, upgrade or unlock your wallet.
• Reading them out to someone on a support call or chat.
• Keeping one paper copy in a place where it can be lost or destroyed.

The SEC's guidance is simple: never share private keys or seed phrases with anyone. Requests for them appear again and again in crypto scams.