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@@ -193,6 +193,37 @@ See `docs/invite-pairing-v1.md`. Read it before touching invites, admin authorit - Revocation now works for key delivery (nothing stored survives it) — but **still rotate the GEK**, the ex-member holds the current one +## Keypair bundles and the browser KDF (2026-08-14) + +- The bundle key is **Argon2id 128 MB / t=3 / p=1**, WebAssembly vendored under + `static/vendor/` (CSP forbids external hosts; 12.2 must keep `wasm-unsafe-eval`). + **Do not change the parameters in one place**: `keyderive.js`, the QE harness and + `test_bundle_kdf_parity.py` are held byte-identical by that test, and a mismatch + presents as an account nobody can open +- Bundles carry an `MBK2` marker; the PBKDF2 form is still readable and is + re-encrypted on the next backup. Both keys are derived at sign-in because the + passphrase is deliberately not retained +- Cost is paid **once per sign-in** (650 ms bundle + 239 ms auth_key); reloading a + page derives nothing — the key lives in IndexedDB +- The bundle is stored on **every node its owner joins**. That is what makes a + second browser work, and it is C4: cracking one yields identity keys, hence + content on *other* nodes and the ability to sign as that user. Draft-v5 §7.1 has + the measured numbers. **The passphrase is the wall; the KDF is a speed bump** +- Floor: 12 characters and ~60 estimated bits, enforced client-side only — with the + password split (T1) the hub never sees a passphrase + +## Two lessons that cost four rounds of live testing + +- **`QE/deploy/e2e.py` cannot test `app.js`.** It is a second implementation of the + client, written in the right order by construction: it proves the protocol and + nothing about the SPA. Three ordering bugs passed it and failed in a browser. + `test_spa_ordering.py` exists for that class and is worth extending +- **An unbounded `await` on the hub socket makes a node silently unreachable.** + Three instances found in `maintain_ws`: the offer handler awaited inside the read + loop, `ws.recv()` for auth with no timeout, and `return` on auth refusal ending + the task for good. Symptom is always the same — daemon running, logging nothing, + `connected_nodes: 0`, socket in CLOSE-WAIT. Look there first + **Corrections to remember:** - `punch_nat()` is **not** a NAT traversal stack — one UDP probe, no STUN, no candidate gathering, one ISP validated. **ICE/STUN (WebRTC) is the traversal path**, for native |