feat: bundles sealed per node under the passphrase and the hub's pepper

The session key is M = HKDF(Argon2(passphrase) || pepper, account id); each
node's bundle key and the playlist key derive from it. Bundles are MBK3, bound
to account and node; MBK1/MBK2 are refused by name, never replaced silently.
Playlists move to key v2 and are re-sealed over unreadable node copies.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/profile-page.js b/packages/meshbay-hub/src/meshbay_hub/static/profile-page.js
index d3d06d7..7a309a9 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/profile-page.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/profile-page.js
@@ -141,10 +141,18 @@ export function ProfilePage({ user, onLogout }) {
     try {
       // Re-wrap every reachable node's identity bundle first — if this cannot
       // run at all the account is left untouched.
+      // Both keys from the passphrases, with the pepper this open session asks
+      // for: the old one opens the bundles as they are, the new one seals them.
+      const K = window.MeshBayKeys;
+      const { pepper, version } = await K.fetchBundlePepper(user.token);
+      const oldKey = await K.deriveBundleSessionKey(
+        cpOld, user.username, user.userId, pepper, version);
+      const newKey = await K.deriveBundleSessionKey(
+        cpNew, user.username, user.userId, pepper, version);
       const result = await window.MeshBayTransport.rewrapAllNodes({
         hubUrl: HUB, token: user.token,
         username: user.username, userId: user.userId,
-        oldPassphrase: cpOld, newPassphrase: cpNew,
+        bundleKey: oldKey, newBundleKey: newKey,
         onProgress: setCpProgress,
       });
 
@@ -158,8 +166,8 @@ export function ProfilePage({ user, onLogout }) {
       // Keep this tab signed in with the fresh pair, and move the session's
       // bundle key forward so the next node connection opens the new bundles.
       setAuth({ ...user, token: resp.access_token, refreshToken: resp.refresh_token });
-      session.bundleKey = result.newBundleKey;
-      _storeBundleKey(result.newBundleKey);
+      session.bundleKey = newKey;
+      _storeBundleKey(newKey);
 
       setCpResult(result);
       setCpPhase('done');