Based on the results of the information and communications technologies (ICTs), a new “digital” economy and society are arising. This new computer- and communication-networked environment needs new set of services and technologies besides new rules and values, which determine the behavior of its actors. In the starting phase of information society the Internet, later on the Internet-based technologies (e.g., the Web) have changed the way business was done the world over, and is now changing the way government interacts with citizens and business sector. With the dramatic increase of the Internet as a business tool and the incredible growth of e-technologies have changed not only the economy but the society as well. According to researchers, early e-government was a form of e-commerce as both used Internet-based technology for the benefit of the information society. Today, e-government can be defined as online government services, that is, any interaction one might have with any government body or agency, using the Internet or World Wide Web. As the mobility is an important characteristic of the information society, new e-government solutions apply wireless/mobile networks as well. The insufficient security of many Internet services is an important limitation of using the Internet. Lack of trustworthy security services is a major obstacle to the use of information systems in private, in business as well as in public services. Trust is intimately linked to citizens’ rights, like security, identification, authentication, privacy, and confidentiality. Secure identification, authentication of the users and communication security are main problems in today’s networked systems. These demands for trust and security are valid in an increased extent in case of digital government applications.