“…To avoid the exposure of privacy, effective technical and institutional measures need to be adopted. In the technical aspect, previous studies have done inspiring research in many daily life applications, such as archive management, digital libraries, e-commerce websites, online financial transactions, and personalized information retrieval [50][51][52][53][54][55]. Researchers have proposed a series of effective and low-cost technical methods to avoid user privacy leakage [56][57][58][59].…”