Thank you for your kindness.
At first, in Korea, all companies regster and get Biz ID Num. at the local tax office.
National Tax Service(http://www.nts.go.kr/eng/) has all Biz ID Num.
Unfortunately, the English site doesn't have a function that people search the company by the number.
Even though NTS has this site: http://www.hometax.go.kr, it has only written in Korean.
Plus, We have also this site: http://www.korchambiz.net/ENG/main.jsp
If you join a member at this site, you can search companies by name.
However, this site hasn't all information of companies in Korea.
I think you would better use NTS help desk.
I'm so sorry that I can not help you.