Yuko Arai

Ochanomizu University, Tōkyō, Japan

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Publications (2)0 Total impact

  • Yuko Arai · Chiemi Watanabe ·
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    ABSTRACT: Database as a Service (DaaS), a form of cloud computing, has recently attracted considerable attention. Users require their sensitive data to be protected from a database administrator that serves as a third party managing the data. We have proposed a secure query execution model for such an environment [10, 11]. Key features of our approach are to represent each tuple of each scheme as a plaintext table with one bloom filter index and to replace queries with keyword searches of the bloom filter index. In [12], we have defined an attack model in which attackers guess features of a plaintext table by observing bit patterns of the bloom filter index: further, we considered a defense against such as attack. We must also assume in this model that attackers can access query logs and may infer features of a plaintext table using such query logs. In this paper, we define an attack model by using query logs and propose a method to defend against the attack by executing fake queries.
    Proceedings of the 4th International Conference on Ubiquitous Information Management and Communication, ICUIMC 2010, Suwon, Republic of Korea, January 14-15, 2010; 01/2010
  • Chiemi Watanabe · Yuko Arai ·
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    ABSTRACT: Recently, Database-As-a-Service (DAS) has attracted considerable attention. Users require protecting sensitive data from the DAS administrators. Most of previous studies, which proposed the solutions using cryptographic techniques, assume that a large amount of data will be inserted into the database and new data will be uploaded infrequently. We propose a secure query execution model for such an environment. Our approach is to represent all schemes of each tuple in a plaintext table as one Bloom filter index, and to replace queries with keyword searches of the Bloom filter index. Same values in each tuple are transformed into different values by two-phase encryption. DAS administrators cannot determine the schemes of the original table even if they look view the database and queries. Therefore, our approach is robust against the estimation of schemes in original tables.
    Database Systems for Advanced Applications, 14th International Conference, DASFAA 2009, Brisbane, Australia, April 21-23, 2009. Proceedings; 01/2009