Amid growing concerns over cyber security sparked by recent attacks on computer networks of financial institutions and broadcasting stations, a majority of South Korean online users have been jittery over internet security, a poll showed Thursday.The survey of 300 people aged between 19-49 who use online services via computers and mobile devices such as smartphones was made by DMC Media, a digital media and marketing solution companyThe survey found that nearly 95 percent of the respondents remained nervous about the security of online services used by computers and mobile devices such as smartphones, while only 5.3 percent considered them to be safe.More than 70 percent of the people polled said that an online service provider should take responsibility for the hacking attack on its service, with 19.7 percent saying public institutions should assume responsibility and 7.3 percent saying users themselves should do so.Nearly all of the respondents said that payment services on computers and mobile devices should be protected at the highest security level.According to the findings of the survey, increased concerns over security caused online users to shy away from using mobile devices to make payments and P2P services to share files.A fear of internet security, however, failed to decrease the frequency in use of mobile devices, according to the survey.Three South Korean banks -- Shinhan, NongHyup and Jeju -- and two insurers as well as three TV broadcasters -- KBS, MBC and YTN -- were hit by the cyber attack last month.