Security wonks and paranoids often warn about networking attacks, where bad guys can see everything you do online and take control of your browser. But most of these network attacks are subtle and go unnoticed by victims. How are you supposed to protect yourself against what you can't see? That's the problem Skycure aims to solve with its free iPhone app.

Once activated, Skycure quietly probes every wireless network to which your phone connects, searching for potentially dangerous activity. This isn't about viruses or worms infesting your phone; this is about making sure that the data you send and receive is coming from and going to the right places.

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Starting Up
When you start up the app for the first time, you are prompted to enter your email address for verification purposes. We were briefly confused by the fact that you must tap a URL emailed by Skycure directly from the phone you're enrolling; you can't do it from a desktop or another mobile device. Most apps don't require that you use a specific device to respond to confirmation messages. It's a minor wrinkle; beyond that, setup is a breeze.

Once it's running, Skycure tests each wireless network with which your phone connects. Skycure compares what it sees to a massive database of known attacks, malicious networks, and suspicious behaviors. Skycure does this in real time, which means that the app generates network traffic and uses some battery power in the process. Company representatives assure us that using Skycure has significantly less impact on battery life than making a phone call. Our testing tended to bear this out; we didn't notice any drastic battery drains.

Skycure keeps it simple by packing all the important information onto a single page in the app. If you've never encountered a dangerous network, congratulations! You'll see a message that says "No Incidents." The app also shows another message, reminding you to keep Skycure running.

This might seem a little odd, since most of us are used to simply switching on our security software and then ignoring it. But the technical limitations of iOS mean that Skycure can only do its work while the app is running. Skycure does not need to be "in focus" (that is, on the screen) to operate, but if you shut it down from the task manager yo