Encrypted Notes
Notes are encrypted client-side with AES-256-GCM before being stored in localStorage. Your passphrase never leaves the page.
Saved notes
Each note is sealed with AES-256-GCM. The key is derived from your passphrase using PBKDF2 (310 000 iterations, SHA-256) with a random 16-byte salt.
A different ciphertext is produced each time you save, even for identical plaintext. Export/import to move notes between devices.