RSA Security surveyed Wi-Fi networks used by businesses in London and found an improvement over the last year: RSA found that 66 percent of the networks use WEP; that's up from 37 percent a year ago. Despite all the buzz around security problems with Wi-Fi networks, businesses in London continue to build the networks. RSA found a 235 percent increase in the number of Wi-Fi networks used by London businesses over a year ago.