Dong-Guk Han received his B.S. and M.S. degrees in mathematics from Korea University, Seoul, Rep. of Korea, in 1999 and 2002, respectively. He received his Ph.D. degree in engineering in information security from Korea University, in 2005. He was a postdoctoral researcher at Future University, Hakodate, Hokkaido, Japan. After finishing his doctoral course, he was then an exchange student with the Department of Computer Science and Communication Engineering, Kyushu University, Japan, from April 2004 to March 2005. From 2006 to 2009, he was a senior researcher at the Electronics and Telecommunications Research Institute, Daejeon, Rep. of Korea. He is currently working as a professor with the Department of Information Security, Cryptology, Mathematics, Kookmin University, Seoul, Rep. of Korea. He is a member of KIISC, IEEK, and IACR.