Store passkey metadata in extension storage

[gppmad]

Store passkey metadata in extension storage

Title: Store passkey metadata in extension storage

Description:

After successful registration, persist the passkey (private key + metadata) to chrome.storage.local so it can be retrieved later for authentication.

Acceptance Criteria:

• Store passkey in chrome.storage.local after response is sent to website
• All required fields are persisted
• Data survives browser restart
• Console log confirms storage success
• Tested on https://webauthn.io — verify data persists

Storage Structure:

Location: background.js (handle chrome.storage operations)

Store this data:

{
  [credentialId]: {
    rpId: "webauthn.io",              // Relying party ID
    userName: "user@example.com",     // User identifier
    publicKey: "base64_public_key",   // Public key (base64)
    privateKey: "base64_private_key", // Private key (base64) - UNENCRYPTED for now
    created: "2025-10-28T12:00:00Z"  // ISO timestamp
  }
}

Required Fields:

• rpId — Website domain (from options.rp.id)
• userName — User email/name (from options.user.name)
• publicKey — Base64-encoded public key
• privateKey — Base64-encoded private key
• created — ISO timestamp

Implementation:

1. Receive passkey data from inject.js via content.js
2. In background.js: Store to chrome.storage.local
3. Log storage confirmation to console
4. Handle errors gracefully

Testing:

1. Load extension
2. Visit https://webauthn.io → Register
3. Complete registration flow
4. Open DevTools → Application tab → Storage → Local Storage (extension ID)
5. Verify passkey is stored with all fields

Blocked by: Format and return proper WebAuthn attestation response

Blocks: Add master password encryption to stored private keys