Recovery
What Is a Recovery Seed Phrase? (And What Recovery Words Do in a Notes App)
What a recovery seed phrase is, how BIP-39 works, how it differs from the recovery words in a notes app, and how to store either one safely.
Quick answer: a recovery seed phrase is a list of 12 or 24 words that encodes a secret, most famously the master key of a crypto wallet. Notes apps borrow the format for a simpler job: getting you back in when you forget your passcode. The two are not always the same thing, so it pays to know which one you hold. Either way, write it down on paper and keep it offline.
How does BIP-39 work?
BIP-39 turns random data into words. A wallet takes 128 bits of secure randomness, adds a 4-bit checksum, splits the 132 bits into twelve 11-bit chunks and maps each chunk to one of 2048 words. The list is designed so no two words share their first four letters, which makes short backups possible.
The numbers are large: about 2^128 possible phrases, the same security level as AES-128, far beyond any brute-force attack with known hardware. A 24-word phrase carries 256 bits. The format caught on because “witch collapse practice feed shame open despair creek road again ice least” survives a handwritten backup; a hex string often does not.
Why do private notes apps use recovery words?
Private notes apps use recovery words because they have no account and no email reset. If you forget your passcode, nobody at the company can let you back in. A set of words you wrote down at setup is the fallback. In zero-knowledge apps the words also unlock the encryption key; in others they only prove you are allowed to reset the passcode.
In a zero-knowledge service, the provider never holds your key, so a recovery phrase or recovery key is the only way back after a forgotten password. Lose both and the data is gone. That is the same lesson crypto wallets taught in 2013.
What do Secure Notes recovery words do?
Secure Notes shows you 12 recovery words right after you set your passcode. If you forget the passcode, typing the words back lets you set a new one. There is no account and no email reset, so the words are your way back in. What they do under the hood differs between iPhone and Android, and we want to be exact about it.
- iPhone and iPad:the words come from the app's own word list (not BIP-39) and are kept in the device Keychain. They verify that you may reset the app passcode. They are not an encryption key: notes on iPhone are protected by iOS Data Protection and the app lock, as explained on our security page.
- Android: the words come from the BIP-39 English list. The app runs them through Argon2id to unwrap the master key of the AES-256 encrypted vault, so they are a real cryptographic recovery path. The phrase itself is never stored, only the wrapped key.
On both platforms the same advice applies: write the words down, do not keep the only copy inside the app, and store them like you would a spare house key.
How should you store a recovery phrase?
Write it by hand, keep the main copy somewhere fire-resistant, and keep a second copy in a different building. Never store it as a screenshot or in a synced document. The right setup depends on what the phrase protects: a crypto wallet deserves steel and a safe deposit box, a notes app passcode reset needs at least a safe paper copy.
| Storage method | Fire resistance | Theft resistance | Recommendation |
|---|---|---|---|
| Paper in a drawer | None | Low | Short-term only |
| Paper in fireproof safe | Medium (1 to 2 hours) | Medium | Good baseline |
| Stainless-steel plate | High | Medium | Best long-term |
| Safe deposit box | High | High | Best for inheritance |
| Screenshot or cloud doc | N/A | Very low | Never |
| Password manager (independent) | Cloud-replicated | Depends on master password | Acceptable secondary |
Practical playbook:
- Write it once, on paper, by hand. Do not paste it, say it to a voice assistant, or type it into a device with cloud sync.
- Store the primary copy somewhere fire-resistant. A small home safe rated for at least 30 minutes is fine for most people.
- Make one copy in a separate location.A sealed envelope at a relative's house, a safe deposit box or a lawyer's office. House fires are a common reason phrases disappear.
- For high-value wallets, use a steel plate. Stamping the first four letters of each BIP-39 word on stainless steel survives fires that destroy paper.
- Never split a phrase naively.Keeping words 1 to 6 in one place and 7 to 12 in another weakens it, because whoever finds one half needs to guess far less. Use Shamir's Secret Sharing if you truly need split storage.
If the phrase belongs to a crypto wallet, our guide to storing a crypto recovery phrase compares every option by threat model, including why a notes app should only ever be a secondary copy.
What happens if you lose it?
With a crypto wallet or a zero-knowledge service, losing both your password and your phrase usually means the data is gone, because nobody else holds the key. With Secure Notes, losing the passcode and the recovery words means you cannot unlock the app, and we cannot reset it for you because there is no account.
A recent backup softens that risk. The iPhone app's Pro Encrypted Backup (version 3.8.1 and later) and the Android app's backup file are both encrypted with a password you choose, so keep that password with your recovery words. For planning beyond your own lifetime, read what happens to iCloud notes when you die: leave instructions in a sealed envelope with an executor rather than handing out passwords while you are alive.
The tradeoff is the same everywhere. Services that can always reset your password can also be pressured, tricked or breached into doing it for someone else. Services that cannot reset it give that power to you alone, along with the responsibility to keep the backup safe.
Frequently asked: recovery seed phrases
What is a 12-word recovery phrase?
In crypto wallets, a 12-word recovery phrase is a readable encoding of 128 bits of random data plus a checksum, using the 2048-word BIP-39 list. The wallet's keys are derived from it, so anyone with the phrase controls the funds. Other apps use 12 words differently, for example to unwrap an encryption key or simply to verify that you may reset a passcode.
What do the 12 recovery words in Secure Notes do?
They get you back in if you forget your passcode. On iPhone and iPad, the words come from the app's own word list and are kept in the device Keychain; typing them lets you set a new passcode. They are not an encryption key. On Android, the words come from the BIP-39 English list and unwrap the vault's encryption key via Argon2id.
Is BIP-39 used outside of crypto wallets?
Sometimes. BIP-39, published in 2013 as Bitcoin Improvement Proposal 39, defines a word list and encoding that some non-wallet apps reuse because words are easier to write down than hex. Other services use their own formats, such as 1Password's Secret Key or Apple's 28-character recovery key for Advanced Data Protection.
Can I store my recovery phrase in a password manager?
Yes, as a secondary copy, as long as that password manager does not itself depend on the same phrase to recover. Never store a recovery phrase only inside the app it protects, because you would need to be unlocked to read it. A handwritten copy kept offline is still the safest primary backup.
What happens if I lose my recovery phrase?
It depends on what the phrase protects. For a crypto wallet or a zero-knowledge service, losing both the password and the phrase usually means the data is gone for good. For Secure Notes, the recovery words are the way back in if you forget your passcode, so losing both means you cannot unlock the app. Keep a backup.
Is a 12-word seed as secure as a 24-word seed?
For practical purposes, yes. A standard 12-word BIP-39 seed carries 128 bits of entropy, far beyond brute force with any known hardware. A 24-word seed carries 256 bits, which adds margin against future quantum search. The weak point is almost always how the phrase is stored, not its length.
How do I back up a seed phrase without a computer?
Write it by hand with a permanent pen and store it somewhere fire-resistant, such as a home safe, with a second copy in a separate location like a safe deposit box. For long-term durability, stamp it on a stainless-steel plate. Never photograph it or save it in a synced cloud document.
Keep reading
Related guides
Crypto
How to store a crypto recovery phrase
Threat models for paper, steel, password managers and notes apps.
Encryption
Zero-knowledge encryption, explained
Why real zero-knowledge services cannot reset your password.
Security
Storing passwords in a notes app
When it's safe, when it isn't, and the rules to follow.
