The keys to your vault

The SHTERA vault encrypts each folder with its own key (the DEK), wrapped several different ways: with the master password, with a 24-character recovery code handed out when the account is created, with a WebAuthn PRF-compatible passkey, and with a backup copy kept for the case of losing all three of those at once.

That backup copy (the rescue key) doesn’t live on this server: it lives encrypted on a small, separate machine, on another provider, that accepts no inbound connections from anyone. Recovering access with it requires verifying identity with a small charge to the card on file (between US$ 0.01 and US$ 5.00, with a code in the description) — without that confirmed charge, the rescue key is never touched. This isn’t a promise that nobody can open the vault under any circumstance: it’s the guarantee that opening it requires going through a separate, audited, verified mechanism, never a direct path from this server.

That guarantee depends on the code running in your browser being the code we say it is: like any service used from the web with nothing installed, it’s the server that delivers that code on every visit. SHTERA doesn’t hide this — it’s the same limit any zero-knowledge vault has when served this way, without a dedicated application installed on your machine.