Firefox password protect on entry

Question

I'm looking for an add-on to the Firefox browser that will allow me to password protect the browser on startup. I would like the add-on to meet these requirements,

• Works on Windows 10 (I don't know how it wouldn't, though)
• Password can be simple and as short as a 4 digit pin
• Is gratis

Some features that are not requirements but wanted are,

• Encrypts the firefox user data directory
• Times out after a certain number of failed attempts
• Provides a log of entries and/or failed attempts

Answer 1

An add-on I have been working that meets just my requirements (not wanted features) is called StartupMaster. It's simple and easy to use where you can simply set a password and every time you load the browser, it will ask for that password before allowing entry to the browser itself. It works on Windows 10 and is gratis.

StartupMaster (gratis)

This extension is a minor enhancement for Firefox & Thunderbird. It asks your master password every time you start the application before the main window is displayed. If there is no master password set, the extension does nothing.