Security
How we protect your data.
ErtiNote is designed so that a stolen or leaked vault file is useless without your master password. Here is how it works — and where its protection ends.
Status: ErtiNote is in development. No independent audit of its code or cryptography has been carried out yet.
Principles
Local first
Your vault is a file on your device, and the app makes no network requests.
Encrypt everything
Contents, names, folder structure and item count are encrypted, not just the text of your notes.
No custom crypto
Only established, open-source primitives from the RustCrypto project.
No back doors
Your master password is never stored. Nobody, including us, can recover it.
Fail safely
Damaged or tampered data is detected and never handed out silently.
Say what we don’t do
Limits are documented as clearly as the protections.
Cryptography
- Encryption
- XChaCha20-Poly1305 with a new random 192-bit nonce for every encryption
- Key from password
- Argon2id v1.3, by default 128 MiB of memory, 3 passes, 4 lanes
- Sub-keys
- HKDF-SHA-256
- Random numbers
- The operating system’s cryptographically secure generator
- Files
- 1 MiB blocks, each encrypted and authenticated separately; SHA-256 checked before export
The data key is wrapped with a key derived from your master password. After unlocking, the password and intermediate keys are wiped from the app core’s memory.
What ErtiNote protects against
A stolen or leaked vault file
From a USB drive, a cloud folder or a disk backup: contents, names, folder structure and item count are encrypted, and Argon2id slows down password guessing.
Tampering and corruption
Changes to the file, its sections or their order are detected when it is decrypted.
Interrupted writes
Atomic writes with verification never leave the vault half-written after a power cut or a full disk.
Malicious content
Raw HTML in notes is not rendered, remote images are not loaded and archive paths cannot escape the target folder.
Rollback
ErtiNote warns you if a vault is replaced by an older version of itself on the same computer.
Where protection ends
A compromised device
Malware running as you — a keylogger, a screen recorder, a memory reader — can capture your password or your open vault.
Weak passwords
Argon2id slows guessing, but it cannot save a short or common password.
Memory and swap
The operating system may write memory to disk. Use full-disk encryption such as FileVault, BitLocker or LUKS.
Clipboard and exports
Copied text and exported or externally opened files leave the vault and are no longer protected by it.
File metadata
The vault’s total size, modification time, name and location are visible, and block counts reveal approximate file sizes.
Deleted data until compaction
Deleted items remain encrypted inside the file until the vault is compacted.
This website
This site is static. It sets no cookies, runs no analytics or tracking scripts and loads no third-party resources; fonts are served from our own server. The only things it stores in your browser are your theme and, if you pick one, your language.
ErtiCloud Backup (planned)
The planned backup service is designed around the same principles: backups encrypted on your device before upload, and the service entirely optional. We will publish its security design before it launches.
Reporting a vulnerability
If you believe you have found a security issue in ErtiNote or this website, please email us with the details and steps to reproduce. Give us a reasonable time to fix it before disclosing it publicly. We don’t run a bug bounty programme at this time.
Report a vulnerability