End-to-end encrypted file collaboration on storage you own. Zero-knowledge, no servers to trust, no subscription.
Cloud storage in 2026 ships with built-in co-pilots, AI search, and "data improvement" clauses. Kerveros encrypts every file — including filenames — on your machine before it touches any provider, so your storage provider and any AI it bolts on later see only opaque blobs. Bring your own S3-compatible bucket (Tigris, Backblaze B2, AWS S3, MinIO), keep your keys, and collaborate with atomic file locks and a tamper-evident audit trail. €79 one-time for one user on any number of devices, with a year of updates and a 14-day free trial. A Team license (up to 5 users) is €299.
Zero-knowledge encryption — XChaCha20-Poly1305 + Argon2id
Bring your own S3 bucket — you hold the keys
Cross-platform desktop — macOS, Windows, Linux
One-time purchase, no subscription
Small teams handling medical records, legal documents, or financial data
Anyone whose cloud provider's terms grant "service improvement" rights over uploads
Teams that need an audit trail of who edited which file, and when
No. Files are encrypted with XChaCha20-Poly1305 before they leave your machine. The manifest that maps file IDs to file names is also encrypted — the provider can't even see what files you have, only opaque blobs.
They can train on what they can read. Kerveros never gives them readable content — each blob is XChaCha20-Poly1305 ciphertext, and no algorithm extracts useful signal from ciphertext without the key. If their terms grant rights to "use" your content, those rights apply to ciphertext — worthless to them.
No. The onboarding wizard walks you through picking a provider (Tigris is recommended — 5 GB free, no card required) and links to their signup page. You enter your access key and secret key once, and Kerveros handles the rest.
Your files are unrecoverable. The passphrase derives the encryption key — we never see it, store it on a server, or have a backdoor. Save it in a password manager before you upload anything important.
Your key comes from Lemon Squeezy, the payment processor. The app activates it online once, then revalidates on launch and about once a day, with a 14-day offline grace window so it keeps working without a connection. That check only confirms the key is valid — it never sees your files, filenames, or passphrase, which never leave your machine. If a purchase is refunded, the key is disabled and stops working.
Nothing breaks. The version you have keeps working forever. Renewing for another year of updates is optional — most users renew because security fixes are part of updates.
Kerveros — €79
End-to-end encrypted file collaboration on storage you own. Zero-knowledge, no servers to trust, no subscription.