The security of wireless networks will always be vulnerable to unscrupulous folks simply because it's out on the airwaves.. A determined, knowledgeable individual, given enough time, will eventually figure out the way to access your data. It's a little like throwing a baseball from one person to another.. You can throw the ball fast, or slow, or toss a curve ball, or hide it with pink feathers, but a person standing in the middle will eventually figure out how to snag that ball if they want to.
So...if you want better security, don't use wireless.. Still, most can create a fairly secure system with a little bit of work and knowledge. I do it for small companies and generally follow a few precautions. If you want to secure you wireless system to the best of its ability, start by limiting the amount of distance the signal will travel.. Lots of folks want the strongest signal they can get but I recommend to my customers that you only want a signal that will travel to your intended computer recipients, nothing more.. If you need to, buy or make a directional antenna so most of the signal will only travel in the direction you prefer. You don't want the signal available to everyone in the neighborhood. If you're only going to be connecting in a room immediately next to the wireless router, try removing the antenna completely and see if it will reach you.
Once you've limited the amount of signal distance, then be sure you have a wireless router and computer which support the latest WPA2 encryption security options. Also be sure to use the most current firmware for that router. Then, create a unique router ID and password to access the router settings (don't use the defaults because such items are known by any cracker worth his/her salt), and be sure to adjust the router so ONLY wired connections can change those settings.. It requires that you create all settings using a wired connection first. After the settings are created, you can unplug the wired connection if you choose and use only wireless but the critical settings must be altered only through a wired connection.
During the very initial setup you can temporarily disable the firewall to verify that you have internet access, etc., but after that, set the router firewall to medium or high.
Once the router access ID and password are created, then set up the wireless internet access password using WPA2 encryption.. Make the password as long as possible using both upper and lower case letters, numbers, and other characters.. Once that's done, change the password often.
And the single most important item for things like credit cards and online banking, DON'T click on links provided to you in email regarding those accounts.. The most common way to snag identity and credit card info is to "bait" the user into following a false link to a site which is able to rob your input.
Hope this helps.
I am a man in my 70's, who enjoys building, repairing and servicing desktop computers, as a hobby. Due to the fact that I need to update or download files from the internet, I thought that a wireless connection would be the best solution. About 2 years ago, I bought a netgear wireless router, together with a netgear USB adapter, and using both I made a network by which I could connect to the internet wirelessly. I had been using this method for about 2 months, when the credit card company, whose card I used to fulfil transactions on the internet, contacted me by telephone, and informed me that some fairly large transactions had been made from my credit account, which they believed were fraudulent. One of these transactions was to pay a hotel bill, of over