iTouchSecure cydia tweak allows you to use the Touch ID to autofill EVERY password.
Don’t bother to type in a password again! iTouchSecure makes it as easy as putting your finger on the Homebutton. All passwords are stored securely in your local Keychain like Apple does. iTouchControl autofills any password in any password entry (those which hide what you type in) for all Apps and if you use Safari’s autofill function with it even all websites.
Password autofill also works on devices without Touch ID.