Summary: Allow users to set a separate, simple 4-6 digit PIN (or biometric shortcut) specifically for unlocking designated "Low-Risk" vaults (e.g., shopping, subscriptions), independent of the main Proton Account master password.

The User Problem: Currently, accessing any vault requires entering the full, complex master password. This creates two issues:

Friction: Users need frequent, quick access to low-value accounts (shopping sites) but must endure typing long, complex passwords repeatedly.
Security Trade-off: To avoid typing the complex password often, users might be tempted to keep their browser tab open longer or choose weaker master passwords, increasing risk for all data.
Proposed Solution: Implement a tiered unlock system within a single account:

Master Unlock: Full Proton Account password required only once per session or for "High-Risk" vaults (Banking, Financial).
Vault-Specific PIN: Allow the user to assign a short, easy-to-enter PIN (e.g., 1234) to specific vaults.
When the user clicks to fill a password from the "Vendor" vault, a small popup requests only the 4-digit PIN.
The "Financial" vault remains locked by the master password (or auto-locks immediately after use).
Benefit:

Speed: Instant access to shopping/vendor logins with a 4-digit entry.
Safety: High-value credentials remain protected by the strong master password and never exposed to keyloggers during frequent low-stakes logins.
Usability: Encourages users to keep all passwords in one secure place rather than splitting them between a manager and their own memory for convenience.