To view or retrieve wifi keys or passwords stored on an Android device requires a root (androidjefe.com/root). It is currently impossible to obtain this information from the phone without root.
Fulfilled this requirement, there are two ways to recover all passwords wifi networks to which you connected the device: the easiest way is to install an application such as Wifi Key Recovery. The other way is without installing applications (manually) Android simply looking within the file that records and stores the keys to the wifi network to which the cell was connected through a file browser with root access.
Easy mode: Wifi Key Recovery
When opening the application will jump screen Root Access application where you have to play on "Allow". Immediately you see the respective wifi key and SSID (network name) of each and every one of the networks it is connected mobile. You can copy or easily export this information to a .txt file.
Wifi Key Recovery on Google Play
Manual Mode: Using a file explorer
File wpa-supliccant.conf the Samsung Galaxy S3 mini with root
File wpa_supliccant.conf a mini Samsung Galaxy S3 with root
Here is a ROOT files like Root Explorer Browser (Root Browser on Google Play) is necessary. In this case we must be located in the / data / misc / wifi. In there must be the wpa_supplicant.conf file that is he who keeps the keys wifi. This file can be opened with any text editor installed on your phone, but if you do not have one you can find several in Google Play.
This can also be done with a file explorer like ES File Explorer, but in this case you must first enable the root Explorer tools in this application and approve the application root. An explorer is useless NO root directory that said above is blank.
As stated at the beginning, recover wifi password stored in Android is impossible without being root.