Private Web Search Using Proxy-Query Based Query Obfuscation Scheme.

People use web search engines to retrieve information from the world wide web. Search engines maintain query logs to refine retrieved information for personalized web search. The query log includes information of users, both sensitive and non-sensitive. If utilized against an individual, the query log may pose privacy concerns and reveal a lot of information about them. In recent years many private web search (PWS) schemes have been proposed to realize privacy-preserving web search. Although each PWS scheme claims to have unique features for attaining web search privacy (WSP), no study explains which private web search characteristics should be considered when building and utilizing a PWS scheme. There are two objectives of this article. In the first part of the article, we present a novel PWS scheme that uses a proxy-query-based query obfuscation approach. Proxy-query-based query obfuscation is a new study topic in PWS research. It provides an IR facility for retrieving information from web search engines via proxy queries. One clear advantage of the proposed scheme is that users do not issue true queries to search engines for retrieving information. The article's second objective is to define the characteristics of PWS and analyze modern PWS schemes on these characteristics. We analyzed proposed and modern PWS schemes on the PWS characteristics. The analysis demonstrated only the proposed PWS scheme achieves all characteristics. Existing PWS systems have been discovered vulnerable to WSP attacks since they do not meet all PWS characteristics.