Kazuhide Fukushima

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Abstract. In Shamir’s (k, n)-threshold secret sharing scheme (threshold scheme), a heavy computational cost is required to make n shares and recover the secret. As a solution to this problem, several fast threshold schemes have been proposed. This paper proposes a new (k, n)threshold scheme. For the purpose to realize high performance, the proposed scheme(More)
Recent years have seen a dramatic increase in the number and importance of mobile devices. The security properties that these devices provide to their applications, however, are inadequate to protect against many undesired behaviors. A broad class of such behaviors is violations of simple informationflow properties. This paper proposes an enforcement system(More)
Recent years have seen a dramatic increase in the number and im-<lb>portance in daily life of mobile devices. The security properties that<lb>these devices provide to their applications, however, are inadequate<lb>to protect against many undesired behaviors. A broad class of such<lb>behaviors is violations of simple information-flow properties.<lb>This(More)
This paper proposes a formal model of the Android permission scheme. We describe the scheme specifying entities and relationships, and provide a state-based model which includes the behavior specification of permission authorization and the interactions between application components. We also show how we can logically confirm the security of the specified(More)
Since the source code of Android was released to the public, people have concerned about the security of the Android system. Whereas the insecurity of a system can be easily exaggerated even with few minor vulnerabilities, the security is not easily demonstrated. Formal methods have been favorably applied for the purpose of ensuring security in different(More)
Cloud computing grows as an important keyword to accelerate IT businesses. A feature of cloud computing is distributed architecture based on unfixed nodes, and security risks have been highlighted for cloud computing services. In this paper, we present a novel approach for solving the essential issue of cloud computing: how to protect a program running in(More)