Encrypted similarity search feasible of keyword index search schemes
Hyun A Park · International Journal of Internet Technology and Secured Transactions · 2016
Encrypting information has been regarded as one of the most substantial approaches to protect users' sensitive information in radically changing current and future computing environments, especially for cloud datacentre whose server manager cannot be guaranteed trustworthy. In prior research, researchers have considered similarity search over encrypted documents infeasible, because the single-bit difference of a plaintext would result in an enormous bits difference in the corresponding ciphertext. However, this work proposes a novel idea of encrypted similarity search feasible of keyword index search schemes (ESS-KIS) over encrypted documents by applying character-wise encryption with approximate string matching to keyword index search systems. The security requirements of similarity search over encrypted data are defined, and two similarity search schemes are proposed. The first scheme is more efficient, while the second scheme achieves perfect similarity search privacy. Surprisingly, the second scheme turns out to be faster than other keyword index search schemes with keyword-wise encryption, while enjoying the same level of security. The proposed schemes ESS-KIS support 'like query ('ab%')' and a query with misprints. That is, this paper has the meaning of making the infeasible encrypted similarity searches into feasibility.