In our paper we argue that the building of trust in electronic commerce depends only partly on technical security and the knowledge of security gaps and ways of closing them. It is not only a technical system which is trusted but rather a socio-technical system, including users, business practices and related institutions. We will take a closer look at the concept of trust and its relation to knowledge, describe the current situation in electronic commerce, and analyse different technical approaches, that aim at providing security, and nontechnical possibilities to enhance security and trust through institutions.