Basic Information

Information Security Laboratory
Senior Associate Professor
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Courses - Undergraduate
F01 Algorithms and Data Structures, L06 Information Security, M02 Linear Algebra, M03 Calculus
Courses - Graduate
CSC01 Information Security, CSC04 Quantum Information


Computer Science, Statistical Science, Nonlinear Science
Educational Background, Biography
Ph.D. and MS from Department of Physics, Graduate School of Science, University of Tokyo BS from Department of Physics, School of Science, University of Tokyo
Current Research Theme
Computational Complexity, Cryptography, Dynamical Systems, Information Theory
Key Topic
Algorithmic Information Theory, Probabilistic Inference, Secret Sharing
Affiliated Academic Society


School days' Dream
Current Dream
Favorite Books
Messages for Students
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Main research

Visual and Audio Cryptography

The secret sharing (SS) scheme is a cryptosystem which encrypts a secret into multiple shares so that any qualified combination of shares can reconstruct the secret, while no forbidden combination of shares reveals any information about the secret. The visual secret sharing (VSS) scheme encrypts a visual secret into visual shares so that humans can reconstruct the visual secret with their eyes by superposing a qualified combination of visual shares each printed on a transparency. This work proposes VSS schemes in which arbitrary visual secrets can be associated with arbitrary combinations of visual shares.

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Information Security

As the world depends more and more on IT, the growing importance of information security is recognized. We conduct extensive research on information security to use IT appropriately and safely. The topics includes theories of cryptography and secret sharing, IoT including motor vehicles and sensors, security management including human activities, and privacy issues in big data.

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