Storing a seed phrase on iPhone

A phone must not be the only copy of a crypto seed phrase. Wallet makers recommend offline storage, and here is why.

A seed phrase, also called a recovery phrase, is the list of words that can restore a crypto wallet. Anyone holding those words can move the funds, usually with no bank or support line to reverse the transfer. That makes it different from most things people keep on a phone.

The phone must not be the only copy

Your phone can fall in a pool. It can be stolen, erased by mistake or locked behind a passcode you forget. If your only copy of the phrase was on it and your wallet device also fails, you may lose access to the funds for good.

Phones also tend to spread copies around. Take a picture of your phrase with iCloud Photos on, and it uploads to iCloud and appears on your other devices. Searching your library may bring it up, and a screenshot lands in the same place.

A wallet maker’s recommendations

Trezor’s guidance for wallet backups says:

• Do not keep digital copies, including screenshots and emails, because a hacked device can expose them.
• Do not store photos of the backup.
• Treat cloud storage as highly risky, and keep the backup offline.
• Use paper for low cost, knowing it can suffer from fire and water, or use a more durable metal backup.
• Keep multiple copies in separate secure locations.
• Check periodically for fading or damage.
• Share the backup with nobody, and enter it only when your device prompts you.

Those are one company’s rules for its own products. Other wallets have their own instructions, so read yours too.

A sensible offline setup

1. Write the words by hand, in order, and check the spelling.
2. Keep the copies in two separate secure places, so a house fire does not take both.
3. Keep the wallet device somewhere other than next to the phrase.
4. Think about who could find the copies, and who would need them if something happened to you.
5. If your wallet offers a way to check a backup, use it before you depend on the copy.

If you still keep a phone copy

Some people do this despite the warnings, often for small amounts. The risk grows with the value, and each digital copy adds risk. Understand what each iPhone option offers:

• Plain note or photo: the weakest. It opens with the phone and syncs with your account.
• Hidden album: still a photo in iCloud, and it opens with the passcode.
• Locked note with a custom password: adds a secret separate from the phone code, and iCloud accounts get end-to-end encryption. The title stays visible, and Apple cannot recover a forgotten password.

None of these replaces an offline copy.

If your phrase may be exposed

If you stored it on a phone that was stolen, or photographed it and someone else got in, treat it as compromised. Move your funds to a new wallet with a new phrase as soon as you can, following your wallet’s instructions. Then follow the stolen iPhone steps to secure your Apple Account.

Be careful with messages about wallet problems, and with sites asking you to verify your phrase. Asking for those words is a common way for scammers to drain wallets.