| Project/Area Number |
13680405
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
計算機科学
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| Research Institution | Japan Advanced Institute of Science and Technology |
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Principal Investigator |
SOSHI Masakazu School of Information Science, Associate Professor, 情報科学研究科, 特任助教授 (00293142)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2002: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2001: ¥700,000 (Direct Cost: ¥700,000)
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| Keywords | computer security / access control / access matrix models / safety problem / anonymity / model / complexity theory / システム設計・解析 / 非単調システム / 決定可能性 |
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| Research Abstract |
The safety problem in access matrix models is the one to determine whether or not a given subject can eventually obtain an access privilege to a given object. Generally speaking, unfortunately, the safety problem is undecidable. Little is known about protection systems for which the safety problem is decidable, except for strongly constrained systems (e.g., monotonic systems). Therefore, we propose the Dynamic-Typed Access Matrix (DTAM) Model, which extends Typed Access Matrix model of Sandhu by allowing the type of an object to change dynamically. DTAM model has an advantage that it can describe non-monotonic protection systems for which the safety problem is decidable. Especially, with further restrictions, we can show that the problem becomes NP-hard. In this research we formally define DTAM model and then discuss various aspects of it thoroughly.
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