One of todays main security challenges on the web is passwords. You typically have to login at many different sites, and remembering a different password for every site is hard. Unfortunately one of the sites you use will sooner or later be hacked, and passwords leaked. If that password is reused on other sites, the hackers will have access to all your accounts. MasterPassword can help. With one master password, a unique one can be generated for each site. When you need to login, this addon will complete the site password for you. And it is impossible to guess the master password from a site password. Read more at masterpasswordapp.com The MasterPassword algorithm is standardized. You can find app's for Ios, Android, Windows, Mac and Linux. One of MasterPasswords strong points is that neither the master or site password is stored anywhere. The site password is rather generated mathematically every time. This is in clear contrast to many other password managers, like Firefox' built in password manager. If your computer or browser is hacked, solutions where the password is stored can give away all your passwords! Similar dangers exists with cloud based solutions. The MasterPassword addon can of course co exist with other password managers and will stay out of your way until you click the MasterPassword button. If you chose to uninstall the addon, you'll just have to remember the passwords you've generated, or import them into another password manager. Since passwords in MasterPassword are mathematically generated, it is impossible to import other custom passwords into master password. They would have to be stored on your computer, which defeats MasterPassword's working principle. As such, it is convenient to use the Firefox password manager for such passwords, until you find a time to switch a site to MasterPassword. Also note that when MasterPassword enters a password for you, Firefox will behave like you typed it on the keyboard, and prompt you if you want to save it. You can of course accept this, but your passwords will then be stored and risk being stolen. I'd therefore suggest to reject that offer. Protect your accounts on the web - Use MasterPassword