The aspect of security needs more consideration in the area of architectures for multidatabase systems. Particularly, the authentication of users which is a main prerequisite for a successful authorization is not considered sufficiently in current architectures. Due to the autonomy and heterogeneity of the component database systems, the problem of authenticationin multidatabase systems is more complex than in traditional database systems. In this paper, we discuss the foundations and prerequisites for architectures of authentication in multidatabase systems. We present several approaches with respect to different degrees of autonomy and heterogeneity. Especially, we work out the authentication process and show the advantages compared with related approaches.