Privacy
How Klowd keeps your data private
Every Klowd app encrypts your data on your device before it syncs. The key is derived from your password in your browser and never reaches our server — so what we store is a blob we hold no key to.
Most apps that promise privacy are promising a policy: they can read your data, and they are telling you they choose not to. That is worth something, but it survives exactly as long as the company does, and not one day past an acquisition or a subpoena.
Klowd works differently. Your data is encrypted on your device, with a key derived from your password inside your own browser. That key is never sent anywhere. What arrives at our server is a block of ciphertext and nothing that can open it.
This is the model Bitwarden uses for password vaults, adopted here in full — including the uncomfortable part, which is covered below.
- Password stretching
- PBKDF2-HMAC-SHA256, 600,000 rounds, in your browser
- Server-side verifier
- scrypt, over a value that cannot open your data
- Data encryption
- AES-GCM, with a key derived on your device
- What our server can read
- Nothing. It holds ciphertext and no key.
- Ads and trackers
- None, in any app
- Data sold or shared
- None. It is unreadable to us.
Where the key comes from
When you sign in, your browser puts your password through 600,000 rounds of PBKDF2-HMAC-SHA256 — the current OWASP figure — to produce a master key that never leaves the page.
Two separate values are then derived from that master key. One wraps the key your data is encrypted with. The other is what gets sent to our server to prove you know your password, and it is hashed again with scrypt before it is stored.
The important property is that these are siblings, not parent and child. The value we hold to sign you in cannot be turned back into the value that opens your data. Someone with our entire database has ciphertext and a password verifier, and no path from one to the other.
Each app then derives its own key from your account key, on your device, and that per-app key is never stored by anyone. Because the derivation only runs one way, one app cannot derive another app's key.
Your device holds the real copy
Every app keeps a complete copy of your data on your device, and that copy is the authoritative one. Sync is something the apps do in addition — not something they need in order to open.
That is why they work on a plane, in a lift, and with the network off entirely. It is also why a bad connection can never cost you something you just entered.
What this costs you
There is a real cost to this design, and it would be dishonest to bury it.
If you forget your password and no longer have a single device with your data on it, that data is gone. We cannot recover it, because we hold nothing capable of recovering it. There is no reset link that restores access, no escrow copy, no support process that can help.
Those two properties cannot both be true at once: either the server can restore your access, which means it could always read your data, or it cannot, which means a forgotten password is final. Every product claiming both is quietly resolving it in the first direction.
The exposure is narrower than it sounds, because your data is not only on our server — every device you use holds a full copy, and resetting your password from a device that still has it re-encrypts everything under the new one and loses nothing. The losing case requires forgetting the password and losing every device.
To make that case survivable, every app exports an encrypted backup you can keep wherever you like. It is not a settings footnote; it is the thing that makes this design safe to live with.
No ads, because there is nothing to sell
The annual fee is the entire business model. That is not restraint on our part — an advertising business needs to read what you do, and this architecture makes that impossible rather than merely against policy.