we look at the trust issues of digital products. Trust is an interdisciplinary issue, involving at least sociological, psychological, but also technical issues. Our concern will be on the technical aspects mainly with a focus on security and privacy. The remainder of this paper is structured as follows: in section 2 categories of digital products are given and the properties that influence trust are discussed. In section 3 we describe a technical infrastructure with focus on security and privacy for trading digital products. In section 4 - as an example of an innovative digital product and the use of the infrastructure mentioned above - we introduce digital emission permits. Emission permits are very up-to-date because their use is demanded in the Kyoto protocol as a means to reduce the greenhouse gas emissions. This protocol was passed at the conference of the UN Framework Convention on Climate Change in Kyoto and signed and ratified by the industrial countries. It will come into effect in 2005.