Secure k-NN query on encrypted cloud data with limited key-disclosure and offline data owner

Abstract

Recently, many schemes have been proposed to support knearest neighbors (k-NN) query on encrypted cloud data. However, existing approaches either assume query users are fully-trusted, or require data owner to be online all the time. Query users in fully-trusted assumption can access the key to encrypt/decrypt outsourced data, thus, untrusted cloud server can completely break the data upon obtaining the key from any untrustworthy query user. The online requirement introduces much cost to data owner. This paper presents a new scheme to support k-NN query on encrypted cloud database while preserving the privacy of database and query points. Our proposed approach only discloses limited information about the key to query users, and does not require an online data owner. Theoretical analysis and extensive experiments confirm the security and efficiency of our scheme.