An Improved Lindell-Waisbard Private Web Search Scheme

Abstract

In 2010, Lindell and Waisbard proposed a private web search scheme for malicious adversaries. At the end of the scheme, each party obtains one search word and queries the search engine with the word. We remark that a malicious party could query the search engine with a fake word instead of the word obtained. The malicious party can link the true word to its provider if the victim publicly complain for the false searching result. To fix this drawback, each party has to broadcast all shares so as to enable every party to recover all search words and query the search engine with all these words. We also remark that, from a user's perspective, there is a very simple method to achieve the same purpose of private shuffle. When a user wants to privately query the search engine with a word, he can pick another n-1 padding words to form a group of n words and permute these words randomly. Finally, he queries the search engine with all these words.