Want to know how to hack unknown wifi password?, then simply use Cain and Abel to do it as it can decode all the stored wifi passwords in Windows. The steps do it are as follows-

Firstly download the Cain and Abel tool & open it.
Then, select the decoders bar & click on the wifi passwords from the navigation menu. Now, click on the (+) sign button. (We are assuming that you have connected to a secured network before, all the passwords will be shown to you now).
And that's it! Get the passwords along with SSID & encryption type & enjoy.