Scrinium
Available — the free tier is unlimited
A zero-knowledge Markdown editor. Your notes are private on every device, and the server cannot read them.
What it is
Scrinium is a Typora-style inline Markdown editor: headings, lists, tables, task lists, blockquotes and code render as you type, with no separate preview pane. It syncs, and it logs in wherever you log in — browser, desktop, phone — without ever handing plaintext to the server.
How the encryption works
"Zero-knowledge" is a key hierarchy here, not a slogan:
- your password derives a Master Unlock Key with Argon2id
- that unlocks an account key, which unlocks a vault key
- every note gets its own key, sealed with XChaCha20-Poly1305
The server stores ciphertext and an SRP verifier. It is architecturally unable to read your notes — not a promise to behave, an inability to misbehave.
Details that matter
- Search runs on your device. Full-text search happens locally over decrypted content, so queries never reach the server in plaintext.
- Portable by design. Import Markdown, export plaintext or an encrypted backup. A privacy product should still let your notes leave.
- The free tier is unlimited. Unlimited notes, encrypted sync and unlimited devices at no cost. Paid tiers add features, not caps.
- Open and verifiable. The threat model and crypto design are published, so the claims can be checked rather than trusted.
scrinium-note.com