To use the application correctly, you'll need to have a rooted device and the app 'busybox' installed. If not, some of the features won't work.
Wps Wpa Tester is an application with some very interesting features. Besides helping you check the security of your point of access, it also lets you see all the passwords for all the WiFi networks that you've connected to from your Android device.
Requires Android 4.0 or higher