How to hack wifi password ?

Its very illegal to perform hacking wifi just as it is hacking a pc. what you need is a 4gb pin drive and your own wifi hacking program application. I dont know how to do it but thats just the materials you need. be careful what your going to do. The law is, as long as that person paid for the internet bills and you use their internet as much as them, you have to pay 5x as much. and they can sue you for it to top it off.