Can people using my wifi see my banking info?

Question

my brother is in a band and he is shooting a music video. he has 2 people staying w/ us for 5 days to help shoot it. we have wifi and they have a macbook pro and an imac. can they see all of my parents work stuff and banking stuff. can we setup a like guest wireless account so that they can have internet but not be on the same as us? because they need internet so if they are connected they can see all 6 of our computers and all of the info. urgent please help fast!!!

Answer 1

For a very basic answer:  Yes, people can see your banking info using wireless networks.

The thing is though, someone has to be aware of your wireless network, so if you turn off the broadcasting option of sending the network name, this can help, along with securing and encrypting your network with at least WPA.  This will keep curious people away from your network and preventing them from getting any info.  If there is someone who really wants at your network, the only thing against them is time.  If you give them plenty of it, they can eventually get sniffers to collect data of anything you do on your network and collecting it, including username/passwords for any sight you visit.  A tool that could do this is WireShark which can capture the packets and what is inside the packet.

One thing you can do is not use wireless networking, which will prevent any outsider from getting in, but if friends are allowed to use the network, then they are already inside and connected and could just capture data with ease.