Estimating resident registration numbers of individuals in Korea: Revisited

Choi et al's work [1] in 2015 demonstrated that the resident registration numbers (RRNs) of individuals could be conveniently estimated through their personal information that is ordinarily disclosed in social network services. As a follow-up to the study, we introduce the status of the RRN system in Korea in terms of its use in the online environment, particularly focusing on their secure use. We demonstrate that it is still vulnerable against a straightforward attack. We establish that we can determine the RRNs of the current president Moon Jae-In and the world-class singer PSY.