Outsourcing Similarity Search: Encrypted M-Index

Bc. Štěpán Kozák

Master's thesis

Abstract:

Práce analyzuje problém použití podobnostního hledání v cloud prostředí se zaměřením na bezpečnost. Byla navržena obecná metoda, kerá zajišťuje bezpečnost dat nahraných do prostředí cloudu. Tato metoda může být aplikována na libovolnou existující indexovací techniku, která využívá fixní množinu pivotů. Byl implementován prototyp za použití indexovací struktury M-Index. Encrypted M-Index byl testován na několika bázích dat pro vyhodnocení efektivity navrženého řešení.

Abstract:

We propose a similarity index that ensures data privacy and thus is suitable for search systems outsourced in a cloud. The proposed solution can exploit existing efficient metric indexes based on a fixed set of reference points. The method has been fully implemented as a security extension of an existing established approach called M-Index. This Encrypted M-Index supports evaluation of standard range and nearest neighbors queries both in precise and approximate manner. In the first part of this work, we analyze various levels of privacy in existing or future similarity search systems; the proposed solution tries to keep a reasonable privacy level while relocating only the necessary amount of work from server to an authorized client. The Encrypted M-Index has been tested on three real data sets with focus on various cost components.

Keywords

similarity search, encrypted index, m-index, privacy, similarity cloud

Language used: English

Date on which the thesis was submitted / produced: 25. 5. 2012

Thesis defence

• Date of defence: 29. 6. 2012
• Supervisor: prof. Ing. Pavel Zezula, CSc.
• Reader: RNDr. Michal Batko, Ph.D.

Masaryk University

Faculty of Informatics

Master programme / field:
Applied Informatics / Applied Informatics