This App keeps all of your passwords in one place. The App is hidden from the app drawer and you only require a code for accessing it. But shouldn't be that hard to remember just one master code? Using this code in the dialler or Calculator will launch the app automatically.
You can try it out as a 30 day trial and then buy the full version for just as little as $5. (One time Fee)
Here's the official video to get you more informed: