Helping Johnny to Search: Usable Encrypted Search on Webmail System

Abstract

End-to-end encryption is becoming common in messaging applications. E-mail that is the one of most popular a messaging application has several standards and systems in its encryption. However, it is hard to say that e-mail encryption has spread enough. It has been pointed out that there are usability problems in message encryption. Even though various studies on message encryption and usability have been made, there is no study discussing utility function such as searching and sorting. In this paper, the search function is focused. We aim to investigate the usability problems on encrypted search. Therefore, a method that applies encrypted search transparently is proposed at first. The implementation of the proposed method is achieved using Google Chrome Extension for Gmail, and evaluation both performance and usability is conducted. We found that participants do not mind whether the search function is encrypted or not if both have almost identical UI and encrypted search operates at high speed.