honest-but-curious · adj. (crypto) — a server that follows the protocol faithfully, but will learn whatever it legitimately can from the data it routes.
What the server sees.
What it never sees.
Coffre's server is honest-but-curious: it stores ciphertext, routes operations, and fans out notifications. It never holds a key that can decrypt a vault.
Never sees
- plaintext TOTP secrets
- your master key
- your password
- your recovery code
- the contents of any item
Does see
- sealed ciphertext (per-item and per-op)
- device public keys (X25519, Ed25519)
- operation ordering (Lamport counters)
- your email address — for authentication only
- push subscription tokens — for notifications
Audit status.
Coffre V1 has not been externally audited. The crypto primitives are standard and well-studied (XChaCha20-Poly1305, Argon2id, X25519, Ed25519). The integration — how they compose into a product — is what an audit would cover, and we'd welcome one.
Read the full threat modelResponsible disclosure.
Found a vulnerability? Email security@coffre.app. We'll respond within 72 hours. Details in our security.txt.