Privacy is becoming a major issue of social, ethical and legal concern on the Internet. The development of information technology and the Internet has major implications for the privacy of individuals. Studies of private or personal information have related it to such concepts as identifiably, secrecy, anonymity, control, etc. Few studies have examined the basic features of this type of information. Also, database models (e.g., 'Hippocratic' [AKX02] database) for this type of information have been proposed. This paper studies the nature of private information and develops a new conceptual model for databases that contain exclusively private information. The model utilizes the theory of infons to define “private infons”, and develops taxonomy of these private infons based on the notions of proprietary and possession. The proposed model also specifies different privacy rules and principles, derives their enforcement, and develops and tests architecture for this type of databases.