One of Firefox's most convenient features is its ability to save the passwords you use to log on to web sites - like your webmail and online banking - so you don't have to type them in every time. Those saved passwords appear as asterisks in the password field, but did you know how easy it is to see what they are? In Firefox, from the Tools menu, choose Options, and in the Passwords tab hit the "View Saved Passwords" button. Then hit "Show Passwords." Yup, there they are, all your high security passwords in plain text and full sight. I kid you not.

Try it. Right now. I'll wait.

Now consider how easy it would be for your Firefox-lovin' housemate to log onto your Gmail, or the computer-sharing temp at the office to get into your checking account or your other half to discover all your pr0n site logins. (Ok, we're just kidding about the porn. Maybe.) Not such a great feature anymore, eh? Today we'll go over a lesser-known feature in Firefox which secures your saved passwords without requiring you to give up the convenience of those autofilled login details.

Back in that password dialog (Tools menu, Options, Passwords) there's a "Change Master Password" button. This master password is a SINGLE password that will unlock the rest of your saved passwords from prying eyes. It's a password you'll have to enter once a session - so each time you restart Firefox. (Click to enlarge.). In other versions of Firefox this is set in the Security Tab.

When setting the master password, the fox has a neat "Password quality meter" which displays how difficult your password is to crack. Try different combinations of words and numbers and symbols to get this secure-o-meter as high as possible. For example the password lifehacker scored very low on the quality meter, but *l1f3h4ck3r* was about 90% hard to crack. (Click to enlarge image.)

Now, the trick here is to pick something you will NEVER FORGET. In the words of the venerable Firefox, "If you forget your Master Password, you will be unable to access any of the information protected by it." 'Nuff said.

Once your Master Password is set, close Firefox. When you reopen and go to a page where you've saved a password - like Gmail - you'll get a security prompt like so:

This prompt is a bit of an inconvenience, but it buys you the peace of mind that no one else is logging onto your sites without explicit authorization.

Thanks to LifeHacker for this!