Removes the sessionStorage plaintext-mnemonic cache (fixed under the
same commit) and replaces it with a PIN-encrypted blob in localStorage.
No plaintext secret ever touches disk or memory outside the live
BuiltInWallet object.
New js/pin-escrow.js — WebCrypto PBKDF2(50k) + AES-GCM(256). Public
API on window.siriusPin: savePinBlob(mnemonic, pin), tryUnlock(pin),
hasPin(), attemptsUsed(), attemptsRemaining(), clear(), MAX_ATTEMPTS.
Iteration count is lighter than BuiltInWallet's 250k because a 4-6
digit PIN's key space is small anyway; the point is 'not plaintext at
rest,' not brute-force resistance — the durable secret is the full
password.
register-flow.js:
- After a fresh password unlock (Import / Create / Unlock), stepSetPin
offers a 4-6 digit PIN with confirm — skippable with 'Not now'.
Never overwrites an existing PIN blob.
- stepUnlock now shows a numeric PIN pad when a PIN blob is present;
the password field only appears when the user opts to 'Use password
instead' or after the blob was wiped.
- Wrong PIN → increment counter, surface 'N attempts left'. Third
wrong PIN → wipe blob and route to a 'PIN reset' screen that hands
off to the password form.
- Correct PIN → decrypt the mnemonic in-browser, rebuild the
BuiltInWallet, finishSignIn(). Attempt counter resets to 0.
profile-menu.js:
- Sign-out clears the PIN blob (via siriusPin.clear()) alongside the
siriusProfile so the device isn't quick-unlockable with a stale PIN.
All pages that host the sign-in flow now include pin-escrow.js. Same
tabbed layout in stepUnlock — the PIN pad and the password field both
live under 🔓 Unlock, transparent tab-switch works exactly as before.
Verified live:
- Fresh Import → 'Set a PIN' step → 4242 confirmed → blob written
- Reload → PIN pad, 3 attempts remaining
- Correct PIN 4242 → signed in, counter resets to 0
- 3 wrong PIN attempts → 'Wrong PIN — N attempts left' per attempt,
then 'PIN locked — enter your full password to continue', blob
wiped, next reload shows the password form
- localStorage contains only ciphertext + salt + iv + counter; no
plaintext mnemonic anywhere on disk or in sessionStorage.
