Resolve Note Download
Security

How Resolve Note keeps your notes private.

Plain words, no slogans. What protects what, and where the limits are.

On your phone

Every note, checklist, label, notebook, photo and drawing is encrypted with AES-256-GCM before it is written to storage. That data key is wrapped by a key that lives in the Android Keystore, the phone's secure hardware, and never leaves it.

When you turn on the app lock, the data key is also wrapped by what you unlock with: your PIN or password (stretched with Argon2id, 32 MiB of memory, so guessing is slow), a fingerprint-bound Keystore key, a YubiKey, or a PIN and a YubiKey together.

Locked notes

A locked note gets its own key, made from its password with Argon2id. Use one password for several notes or a different one for each. A locked note stays encrypted even while the app is open, until you enter its password.

YubiKey

Resolve Note talks to a YubiKey over NFC or USB using HMAC-SHA1 challenge-response (slot 2). The key's answer is needed to unwrap your data key, so it is part of the cryptography, not just a button. Use it instead of your PIN, or require both for two-factor protection.

Worth knowing

With “PIN + YubiKey”, losing the YubiKey means losing access to the notes on that phone. Keep an encrypted backup.

End-to-end encrypted sync

Sync is off until you turn it on. When you do:

  • Your passphrase is turned into keys on your phone with Argon2id. The passphrase itself is never sent anywhere.
  • A random 256-bit sync key encrypts every item with AES-256-GCM. The server keeps that key only in wrapped form, which it cannot open.
  • Item names on the server are hashes, so it cannot even tell a note from an image.
  • Your account is a random ID. No e-mail, no phone number, no name.

What the server can see: the random account ID, how many encrypted items there are, their sizes and when they change. Like any web service, the network that runs it processes your IP address to make the connection. What it cannot see: titles, text, labels, images or your passphrase.

The honest trade-off

Because nobody else ever has your keys, nobody can reset your passphrase. Save the recovery key you are shown at setup. If both are lost, your synced copy is gone for good. Your notes on the phone are not affected.

Private on screen

  • Block screenshots and screen recording.
  • Hide the app's content in the recent-apps screen.
  • Auto-lock after a time you choose.
  • Wrong PINs add a growing delay; you can choose to erase everything after 10, 15 or 20 wrong tries.
  • Reminders can hide titles; locked notes never show theirs.

What we don't do

  • No ads, no analytics, no trackers. The app contains no code that reports how you use it.
  • No account with your name or e-mail.
  • Android's automatic cloud backup is switched off for this app, so your notes are not copied anywhere you didn't choose.

The limits

No software can honestly promise it can never be hacked. If your phone is unlocked and infected with malware, or someone watches you type your PIN, no app can fully protect you. A short PIN is weaker than a long password. Resolve Note uses well-known, standard building blocks (AES-256-GCM, Argon2id, Android Keystore) rather than home-made cryptography.

Found a problem? Please write to resolvenoteapp@proton.me.