CHICAGO—After exhausting all the obvious candidates, laptop user Ted Murphy concluded Thursday that the Wi-Fi password of the Ostermann family next door must be something pretty good. "Well, this is a tough little nut to crack," Murphy said following a half hour of failed efforts to access the Internet without moving from his sofa. "It's not 'password,' 'ostermann,' '123456,' or the name of any family member or pet. I'll be damned—they really put some thought into this one." If his next 20 or so attempts fail, Murphy said he would just try joining the network known only as Linksys.