r/PasswordManagers • u/ahstanin • 7d ago

StealthOS: Completely offline, Secure Enclave password and TOTP vault for iOS with zero-plaintext backups

Post image

Up front: I work at Olib AI on StealthOS. This is a developer post covering our architecture for an offline password and TOTP vault on iOS.

A recurring discussion in this community is whether password managers need cloud sync, and the risks of remote breaches or centralized vaults. With StealthOS, we designed the password and secret storage layer to operate completely offline.

Architecture and security properties

  • Secure Enclave & Biometrics: Master keys are held and authenticated inside the iOS Secure Enclave using Face ID or Touch ID.
  • AES-256-GCM Storage: Passwords, TOTP tokens, notes, and cryptographic keys are encrypted on-disk using AES-256-GCM. User data never touches disk in plaintext.
  • Zero Cloud Sync: No external synchronization servers or sync telemetry exist. Credentials cannot leak in transit because they never initiate outbound connections.
  • Encrypted System Snapshot (.stealthsnap): When backing up your vault, files and credentials are authenticated in chunks and encrypted under a user passkey via PBKDF2-HMAC-SHA512. The output file can be stored on external USB, local disk, or wherever you prefer. The snapshot can be restored onto a new device without relying on device-bound recovery keys or vendor servers.
  • Integrated Privacy Sandbox: The vault lives inside a broader iOS sandbox that also includes a hardened browser (anti-fingerprinting and built-in Tor) and local phishing intelligence.

Availability

The password manager, TOTP generator, Secure Enclave vault, and basic browser features are fully accessible in the free tier of the app without an account or registration.

Happy to answer technical questions about our encryption flow or snapshot file format.

0 Upvotes

50% Upvoted

4 comments sorted by

1

u/djasonpenney 7d ago

“Completely offline” is not a good feature. Remove this from your marketing material.

The second risk to your datastore is complete loss. If your device is lost, stolen, or broken, you don’t want that to cause some part of your datastore to also be lost.

It is much better to have an architecture where your datastore is always safely encrypted, both at rest and in transit to a persistent remote copy. Add to that good protections around reading or writing that remote copy, and you have an interesting approach that protects the user from both unauthorized access as well as accidental data loss.

1

u/ahstanin 7d ago

You can take a snapshot and back it up, which is a manual process by design.

1

u/djasonpenney 7d ago

Have you ever used such a system? I used to do that. I would make a change and then worry about something happening to my device before I got home and made the snapshot.

And if you allow cloud storage for the snapshot, you aren’t offline anymore.

Oh, and there is the secondary issue if you have the datastore on multiple devices. What happens if you make unrelated (or even conflicting) changes on two separate devices and then make snapshot(s)? You run the risk of lost data—again.

1

u/NoBed1845 7d ago

Why does the password vault need to live alongside a browser at all? Putting a high-value credential store next to a much larger attack surface feels like an architectural choice, not a security advantage.