Introducing the technological step into this new 3^rd millennium, advanced communication means like global networks including the Internet become more and more important for a fast and convenient information exchange across regional and even national borders. Concerning the sector of public and private healthcare and welfare, new health information system, or citizens’ information systems in general, are coming up to meet the needs of the whole information society. Thus, developing and implementing those systems is one of the most important aims of the present and the near future. Access to, and communication of, relevant patient-related administrative and medical information items always means a secure and trustworthy way of dealing with data. Concerning the main aspects of specific legal, social, ethical, technical, organisational, and even political requirements for secure access and secure communication of health data in terms of data protection, data security, privacy, safety and quality using unprotected networks as, e.g., the Internet, there is a strong and even growing need for the fundamental technology of Trusted Third Parties to meet the whole range of the security categories as integrity, confidentiality, availability, accountability, and access control.