South Korea's national identity card system may need a complete overhaul following huge data thefts dating back to 2004.
The government is considering issuing new ID numbers to every citizen aged over 17, costing billions of dollars.
The ID numbers and personal details of an estimated 80% of the country's 50 million people have been stolen from banks and other targets, say experts.
Rebuilding the system could take up to a decade, said one.
Some 20 million people, including the president Park Geun-hye, have been victims of a data theft from three credit card companies.
"The problems have grown to a point where finding a way to completely solve them looks unlikely,'' technology researcher Kilnam Chon told Associated Press.
There are several reasons that the ID cards have proved so easy to steal:
- Identity numbers started to be issued in the 1960s and still follow the same pattern. The first few digits are the user's birth date, followed by either a one for male or two for female
- Their usage across different sectors makes them master keys for hackers, say experts
- If details are leaked, citizens are unable to change them
- The government required net-users who wanted to deal with banks or shops online to use a Microsoft product, ActiveX, to provide a digital signature but critics say it was a simple password that could easily be duplicated
The news will be an embarrassment for a country that has gained a reputation as one of the most tech-savvy nations in the world.
About 85% of South Korea's people are online, many with super-fast net access. The country's population owns 40 million smartphones.