Wifi Master Key for Android
1: You need root to use this application.
2: You need to have connected to the network in the past.
3: This app cannot "hack" into an unknown/new network.
4:For rooting your device , Have a look at http://forum.xda-developers.com for that.
Have you ever forgotten the password of your home WiFi network, or the one you setup for your parents a few months back?
This application will help you recover the password of a wireless network you have connected to with your device in the past.
Note:
It does not crack the network, or use the MAC/SSID address to deduce the password. It simply reads it from the device itself.
Essentially it parses the wpa_supplicant file.