More than 4.98 million users of Google Inc's Android-based operating system were infected with Trojan horse viruses from cell phone applications in 2011, with 8.53 million computers hit by attempted attacks each day, an increase of about 50 percent year-on-year, according to a report released by China's top industry regulator and Internet safety giant Qihoo 360 Technology Co on Tuesday.

Online privacy protection has been a hot topic in the country since China's Internet population reached 513 million to become the largest globally, according to a China Internet Network Information Center report in January.

About 300 million people use micro blogs, a massive increase since 2010.

China has about 300 million micro-bloggers, said Liu Zhengrong, deputy director of the Internet department of the State Council Information Office.

The China Center for Information Industry Development, a research institution affiliated with the Ministry of Industry and Information Technology, released the report about online personal information on Thursday.

"The situation is not very good. Most of the websites and cellphone applications we tested do not inform customers about how their information would be used," said Gao Chiyang, executive president of Beijing CCID.

He added that according to the research, the security situation regarding personal information at 105 popular Chinese websites was "not looking good" and on mobile devices it was "very serious".

Among popular e-commerce websites including Taobao, Amazon and 360buy, the latter got the lowest score because it lacked explanations and supervision of how customers' personal data was used.

To protect their personal information online, people should avoid using the same password for different websites and install official operating systems and antivirus software, suggested Tim Cranton, chief legal consultant for the Greater China Region at Microsoft Corp.

"About 60 percent of Internet users have encountered personal data losses online, according to our survey," said Liu Jiuru, deputy director of the information technology ministry's Electronic Technology Information Research Institute.

However, because it is not easy to get evidence of such violations, only 10 percent of customers complained about data violations, said Liu. "About 75 percent of Internet users called for online information legislation," he said.

"While an Internet user is online, their private information will be displayed without their knowledge," said Qi Xiangdong, president of Qihoo 360.

Qi said that such private information could include real identities, property information, family data, e-mail and password information and even browser history and search behavior.

He added that 50 percent of Internet users had frequented the online shopping website Taobao, while about 40 percent had registered micro blogs. "Websites should set up specific departments to protect customers' private information," said Qi.

China will speed up the passage of laws to protect online personal data, said Ouyang Wu, deputy general director of the ministry's Department of Information Security Coordination.

tuoyannan@chinadaily.com.cn