Photo of Shuichi Katsumata


Shuichi Katsumata

A cryptographer is spearheading global developments in "post-quantum cryptography."

Year Honored


R&D aimed at the commercialization of large-scale quantum computers is gaining speed around the world. Despite the excitement, there is a fear that the commercialization of quantum computers may break our current encryption methods that are deemed secure by virtue of the enormous amount of time it takes for conventional computers (i.e., classical computers) to break them.

Because of this, the development of "post-quantum cryptography," a technique that can ensure security even against quantum computers, has become an urgent task. Shuichi Katsumata is a researcher and the first to successfully secure the final step of the "Signal Protocol," the most popular secure messaging protocol (SMP) with 200 million users worldwide, by making it resistant to quantum computers. In addition, he has been working on addressing SMP-related issues with cutting-edge ideas, including devising methods to significantly enhance the security and scalability of next-generation SMPs currently being standardized by the Internet Engineering Task Force (IETF).

Messaging tools such as Slack and LINE have permeated both the business world and the everyday lives of individuals, and have now become one of the most popular means through which information is communicated. However, it has been pointed out that these platforms remain vulnerable to serious privacy risks, including the leakage and misuse of personal information. Although SMP is a next-generation privacy protection technology that has been gaining attention in recent years as a potential solution to this problem, it was plagued by scalability issues and lacked a design approach that can make it resistant to quantum computers. Katsumata's innovation will not only protect the privacy of communications for countless people but also bring us a step closer to fully protecting the diverse forms of communications used in our information society from the threat posed by quantum computers.