In this paper, the authors present a strong authentication method by examining each user with certain private information related to that user. The proposed method constructs a database for all authenticated users. Each record in this database is assigned to individual users. Some of the fields of user's record are subjected to the user as private questions and the user must answer these questions randomly with a suitable weight assigned to each question. The most important property of this method is that the user for certain privileges must answer some selected candidate questions private to a system group.