March 26, 2021

Winner of the Best Paper Award at the Most Selective International Conference in Cryptography

Secure System Research Laboratories
Akiko Inoue

After receiving a master's degree in mathematics, Inoue joined NEC in April 2017. She is engaged in the mode development of symmetric key cryptosystems and the analysis of existing cryptosystem. In 2019, she received the Best Paper Award at CRYPTO, which is the top conference in the field of cryptography.

Pointing out the vulnerabilities in the cryptosystem which were believed to be absolutely safe

I am currently assigned to the Security Research Laboratories at NEC where I am conducting research of cryptography. The main theme of my work is mode development within symmetric key cryptosystems. Recently, I am also working on memory encryption technologies. I also researched cryptography during my student days, but my specialty was public key cryptography. Even within cryptography, it is a field which is a bit more theoretical and academic. After finishing my master's degree, I wanted to become involved in research in the field which was more practical and closer to real world applications and joined NEC, so I feel a great sense of purpose in my current research.
In addition, the analysis of existing cryptosystem is an important mission of our team. In 2019, I pointed out vulnerabilities in OCB2, an authenticated encryption scheme which at the time was believed to be absolutely safe, and received the Best Paper Award at CRYPTO, which is one of the most prestigious international conferences in the field of cryptography. In addition to receiving the Chairman's Award from SCAT (Support Center for Advanced Telecommunications Technology Research) in 2020, that research paper also won an Innovation Paper Award from SCIS, which is a Japanese cryptography conference.
The vulnerabilities were discovered when I was working on improvements to OCB2. While conducting my research, I realized that the security proof for OCB2 was originally mistaken. I consulted with my boss, Mr. Minematsu, and we started to work on correcting the proof together. As we were carrying out this work, Minematsu discovered that these vulnerabilities could be used in an attack. Because this would mean that OCB2 was not safe, we then quickly compiled and announced the research paper. As a result, OCB2 was removed from the ISO international standards. That research was able to make a significant contribution to global data security.

Thinking about research of cryptography from the perspective of real-world applications

I became interested in NEC due to a presentation at a conference. A female team member who is also now working at the same Security Research Laboratories gave a presentation as an NEC researcher, and I recall having the impression that NEC was the kind of company where women could play an active role. At the time, I had not decided yet whether to go on to a PhD or work as a system engineer at an IT firm or education related company after finising my master’s degree. However, when I saw this presentation, I became aware that there was also a path through which I could research cryptography at a company.
The deciding factor in choosing NEC from among other companies was the "people." During my job hunting, I met and spoke with the people at the Security Research Laboratories, and everyone was fascinating and the kind of people that I respect as researchers. Among those discussions, the one that made an impression on me was the discussion with a researcher who said that, "Human error is something that will absolutely happen, so I would like to create cryptosystems which are safe even when human error occurs." It was a discussion that made me feel that this person was researching cryptography from the perspective of people who are actually using it, which was an extremely fresh perspective for someone who was in the academic world at the time. This way of thinking matched my motivation to want to research forms of cryptography which were a bit more practical.

Deepening and expanding an area that I think is enjoyable

Even after joining the company, I feel that I am truly blessed when it comes to the "people." Because NEC is a large company, there are many researchers in various fields. For example, if you have a problem in this area, then you should ask that person. An environment in which there are many people that you can rely on is quite hard to come by. The ability to absorb various essences from many people is also a positive aspect.
Mr. Minematsu, who I mentioned a moment ago, is one of the top cryptography researchers in the world. When we are conducting research together, I get the feeling that he understands the research trends and is truly skilled at predicting where they are heading. Because I believe it is a skill which is essential for growing a step further, I would like to actively learn how to do so through close observation. In addition, Minematsu is also very good at connecting those trends to his areas of interest. Of course, conducting research in your area of interest also increases your motivation. However, in order to do so, you must deepen and expand your area of interest and field of expertise. Recently, I have also started to consciously think about trying to expand the research areas that I find enjoyable. Since I originally started in mathematics, I am also enjoying the study of mathematics and programming outside of my work. I hope that all of the students can also deepen and expand the areas of research that they now enjoy. I strongly believe that is the very thing which will lead to a unique individuality in your own future research.

A day at work

Message to my past self in my school days