Keeping Secrets in Modalized DL Knowledge Bases

Gopalakrishnan Krishnasamy Sivaprakasam, Giora Slutzki


In this paper we study Secrecy-Preserving Query Answering problem under the Open World Assumption (OWA) for ELH Knowledge Bases. Here ELH is a top-free description logic ELH augmented with a modal operator ^. We employ a tableau procedure designed to compute a rooted labeled tree T which contains information about some assertional consequences of the given knowledge base. Given a secrecy set S, which is a finite set of assertions, we compute a function E, called an envelope of S, which assigns a set of assertions to each node of T. E provides logical protection to the secrecy set S against the reasoning of a querying agent. Once the tree T and an envelope E are computed, we define the secrecy-preserving tree TE. Based on the information available in TE, assertional queries with modal operator ^ can be answered efficiently while preserving secrecy. To the best of our knowledge, this work is first one studying secrecy-preserving reasoning in description logic augmented with modal operator ^. When the querying agent asks a query q, the reasoner answers “Yes” if information about q is available in TE; otherwise, the reasoner answers “Unknown”. Being able to answer “Unknown” plays a key role in protecting secrecy under OWA. Since we are not computing all the consequences of the knowledge base, answers to the queries based on just secrecy-preserving tree TE could be erroneous. To fix this problem, we further augment our algorithms by providing recursive query decomposition algorithm to make the query answering procedure foolproof.


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Paper Citation

in Harvard Style

Krishnasamy Sivaprakasam G. and Slutzki G. (2017). Keeping Secrets in Modalized DL Knowledge Bases . In Proceedings of the 9th International Conference on Agents and Artificial Intelligence - Volume 2: ICAART, ISBN 978-989-758-220-2, pages 591-598. DOI: 10.5220/0006202505910598

in Bibtex Style

author={Gopalakrishnan Krishnasamy Sivaprakasam and Giora Slutzki},
title={Keeping Secrets in Modalized DL Knowledge Bases},
booktitle={Proceedings of the 9th International Conference on Agents and Artificial Intelligence - Volume 2: ICAART,},

in EndNote Style

JO - Proceedings of the 9th International Conference on Agents and Artificial Intelligence - Volume 2: ICAART,
TI - Keeping Secrets in Modalized DL Knowledge Bases
SN - 978-989-758-220-2
AU - Krishnasamy Sivaprakasam G.
AU - Slutzki G.
PY - 2017
SP - 591
EP - 598
DO - 10.5220/0006202505910598