An increasing number of people, both inside and outside the science community, are fascinated by the current development and future prospects of what is known under the political or technical keywords, respectively, of "data superhighway" and "global information infrastructure", or "internet" and "world wide web". Fewer people, however, are aware that these facilities are a great challenge for our democratic societies to redefine the balance of power among their users and, accordingly, to invent new technical means to support users in maintaining their security goals of privacy (informational self-determination), confidentiality, integrity, availability, and non-repudiation.