A massive online database apparently containing the personal information of up to one billion Chinese citizens was left unsecured and publicly accessible for more than a year — until an anonymous user in a hacker forum offered to sell the data and brought it to wider attention last week.A massive online database apparently containing the personal information of up to one billion Chinese citizens was left unsecured and publicly accessible for more than a year — until an anonymous user in a hacker forum offered to sell the data and brought it to wider attention last week.