From Nov. 5 to Nov. 25, Hyuntae Kim and Junsoo Kim visited the University of Electro-Communications(UEC) in Japan to meet professor Kiminao Kogiso. One of research topics that he is now actively working on is Encrypted control systems, and he had first introduced the concept to the control system society in IEEE CDC 2015.
“Cyber-security enhancement of networked control systems using homomorphic encryption”
Kiminao Kogiso and Takahiro Fujita
Proc. of 2015 IEEE 54th Conference on Decision and Control, pp. 6836-6843, IEEE, Osaka, Japan, 2015.
Utilizing the ElGamal encryption scheme which allows multiplication over encrypted messages, he and his students implemented the algorithm to a DC motor position controller with their experimental equipment. So, during the visiting period, we had a chance to apply our schemes to the motor controller. The following video shows that the implementation of Hyuntae’s encryption algorithm using “exponential ElGamal scheme” is successful. Even though there are some disturbances by human fingers, the position of the motor follows the reference while all the control signals are encrypted, so they seem just as random signals in the left side of the monitor.
Three weeks staying in UEC was quality time to share many ideas to develop the existing methods. Hyuntae and Junsoo learned a new concept of “key switching” techniques that enhances the security level of the encrypted system, and they shared the idea that implementation of the encryption can be much more efficient when the controller has integer coefficients.
The visitation was meaningful indeed. The students were really impressed with their kindness, and thanks to professor Kogiso and his students, they could enjoy both researches in UEC and life in Tokyo!