NEW YORK--Using a laptop, cell phone headset, building access badge, credit cards, or even a passport can make you a walking target for data thieves and other criminals, a security expert warned at the Last HOPE hacker conference here late Friday.

In a frightening but entertaining session entitled "How do I Pwn Thee? Let me Count the Ways" (pwn is hacker speak for "own" or control), a hacker who goes by the alias "RenderMan" explained how most people are at risk and don't even know it.

By now most people probably know they should be careful using Wi-Fi networks, especially public hotspots that don't encrypt data transmissions and where network access points can be spoofed. These issues leave Web surfers at risk of having their data stolen, receiving fake Web pages and other information, and having their computers completely taken over, he said.

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