Zero-knowledge
by design.
Your data is yours alone. Curtain is built so that even we cannot access your browsing history, shared links, or personal information.
What Curtain never sees
Your Browsing History
We don't track where you go or what you view. Your sessions are private.
Your Personal Data
No personally identifiable information (PII) is ever collected or stored.
The Links You Share
Even we can't see the original URL you seal. It's encrypted client-side.
How sealing works
Sealing happens entirely on your device. The original URL is never sent to our servers in readable form — we only ever handle an encrypted token, and that's exactly what makes Curtain zero-knowledge.
You seal a link
Paste any URL and press Seal Link. Curtain encrypts it right there on your device, with a key that never leaves your machine.
It becomes an opaque token
What gets stored and shared is a curtain:// link — no readable address, no tracking parameters, and nothing that can be reversed without the key.
Only Curtain can open it
Opened inside Curtain, the link is decrypted locally and the real site loads. Paste it anywhere else and it's meaningless.
PIN + Duress Vault Explainer
Secure Your Links with a PIN & Duress Vault.
Protect your sealed links with a custom PIN. In an emergency, use a separate Duress PIN to open a decoy vault, keeping your real data safe.
What Curtain is
- A private link-sharer: Wrap any URL in an encrypted curtain:// link only Curtain can open.
- Zero-knowledge by design: Links are sealed and opened on your own device — never by us.
- Ephemeral by default: No history, no cookies, and no traces once your session ends.
What Curtain is NOT
- NOT a VPN: We don't mask your IP address across all of your internet traffic.
- NOT an Incognito replacement: It shares links privately; it isn't a full browser mode.
- NOT total anonymity: It secures the links you share, not your whole digital footprint.