Hideki Imai (今井 秀樹 Imai Hideki, born 1943 in Shimane Prefecture, Japan) is an information theorist and cryptographer, currently the director of Research Center for Information Security (RCIS), National Institute of Advanced Industrial Science and Technology (AIST) and a full professor at Chuo University. His notable work includes research in coding theory, block cipher design, and public-key cryptography. In 1977, together with Hirakawa, he proposed a coded multilevel signal modulation scheme. The scheme uses several classes of binary error-correcting codes, symbols of which are combined to set up the transmission signal. The scheme is known as Imai-Hirakawa code.[1] He received his Ph.D. in electrical engineering from the University of Tokyo in 1971. He was on the faculty of Yokohama National University from then until 1992, before he joined the faculty of the University of Tokyo. He has been the director of RCIS since 2005. He became a professor at Chuo University in April 2006. He became an IEEE Fellow in 1992, and an IACR Fellow in 2007.[2]