It stores Firefox session data outside the active profile while locked, then restores it after the correct PIN is entered. Pressing Esc in the PIN dialog opens a neutral Firefox profile instead.

Build

Run:

.\Build.ps1

This compiles FirefoxLauncher.exe as a windowless launcher and recreates Firefox.lnk with the normal Firefox icon.

Use

Run Firefox.lnk.
On first setup, choose a PIN.
Use Firefox.lnk instead of the normal Firefox shortcut.

Behavior:

If Firefox is locked, a small dark PIN dialog is shown.
Correct PIN restores the protected session and opens your real Firefox profile.
Esc opens a separate neutral Firefox profile.
Wrong PIN keeps the protected profile locked.
If your real Firefox profile is open and you close it with X, a background watcher locks the session afterwards.

Important Firefox Setting

Disable this Firefox setting:

Clear cookies and site data every time you close Firefox

If Firefox deletes website data on exit, this tool can only protect what is still present after Firefox closes.

What Is Protected

The vault protects:

Firefox cookies
webappsstore.sqlite
selected website storage under storage\default\https...
session restore files

New locks store encrypted .ffsv files in .firefox-session-vault\vault.

Security Notes

This is a practical privacy lock for a shared Windows session, not enterprise-grade isolation.

It does not protect against someone who can modify this folder, kill processes, inspect the same Windows account deeply, or use admin rights. Separate Windows accounts are still the real security boundary.

Do not commit .firefox-session-vault; it contains local encrypted session data.