Secure Notes Tool
Keep a password-locked vault of AES-256-encrypted notes in your browser, and share self-contained encrypted notes with a passphrase. Zero-knowledge, offline-ready and 100% private.
What is the Secure Notes Tool?
Secure Notes is a private, encrypted notebook that runs entirely in your browser. It gives you two things: a password-locked vault — a list of notes encrypted at rest with AES-256-GCM using a key derived from your master password (PBKDF2-SHA-256, 250,000 iterations) — and a share mode that encrypts any note with a passphrase into a single self-contained string you can send to someone, who decrypts it here with the same passphrase. Because it's zero-knowledge, nothing is ever uploaded: your notes, your password and your passphrases all stay on your device. The vault auto-locks when idle, stores only ciphertext in local storage, never keeps your password, and uses a fresh random salt and initialization vector for every encryption. The trade-off of true client-side encryption is that there's no password recovery — if you forget your master password, the notes genuinely cannot be decrypted by anyone, including us.
How to use it
- Create a vault and choose a master password (there's no reset, so keep it safe).
- Write notes — they're encrypted and saved to your browser automatically as you type.
- Lock the vault when you step away; unlock it later with your password.
- Use the Share tab to encrypt a note with a passphrase, then send the encrypted text and passphrase separately.
Benefits
- AES-256-GCM encryption with a PBKDF2-SHA-256-derived key (250,000 iterations).
- A password-locked vault of multiple notes, encrypted at rest in your browser.
- Share mode: encrypt a note into a self-contained string anyone can decrypt with the passphrase.
- Zero-knowledge and offline — nothing is ever uploaded and no account is needed.
- Auto-lock on inactivity, with the decryption key held only in memory.
- Only ciphertext is written to local storage; your password is never stored.
- Fresh random salt and IV for every encryption, with a versioned, future-proof format.
- Change your master password any time — your notes are transparently re-encrypted.
Frequently asked questions
How are my notes encrypted?
With AES-256-GCM, a strong authenticated encryption standard. The key is derived from your master password using PBKDF2-SHA-256 with 250,000 iterations and a random salt, so the same password produces a strong, unique key.
Where are my notes stored?
Only in your own browser's local storage, and only as encrypted ciphertext. Nothing is ever sent to a server — the tool works completely offline once the page has loaded.
What happens if I forget my master password?
There is no recovery. Because the encryption key comes from your password and is never stored, forgetting the password means the notes cannot be decrypted by anyone, including us. Choose a password you'll remember or store it in a password manager.
How does the share feature work?
Share mode encrypts a single note with a passphrase into one self-contained string (starting with TLZ1.). Send that string to someone and tell them the passphrase separately; they paste it into the Decrypt box here to read it. The string contains everything needed to decrypt except the passphrase.
Is this truly zero-knowledge?
Yes. Encryption and decryption happen in your browser with the Web Crypto API. Your password, passphrases and plaintext never leave the page, so there's nothing on any server to leak.
Does the vault lock automatically?
Yes. After a period of inactivity the vault locks and the decryption key is dropped from memory, so you'll need your password again. It also locks whenever you close or refresh the tab.
Can I change my master password?
Yes. While the vault is unlocked, open the Password panel to set a new master password — your notes are re-encrypted with a freshly derived key and saved.
Is it safe to share the encrypted string publicly?
The string is encrypted, but its safety depends entirely on the strength and secrecy of the passphrase. Use a strong, unique passphrase and share it through a different channel than the encrypted text.
Does it work on mobile?
Yes. Creating and unlocking the vault, editing notes, and the encrypt/decrypt share tools are all responsive and touch-friendly.
Is this secure notes tool free?
Completely free with no signup and no limits. The encrypted vault, sharing and all encryption features are available to everyone, privately in your browser.