I’m going to talk about secure group management in ad-hoc networks. This is joint work with Tuomas Aura and it is partly funded by Finnish defence forces. Just when things started to look better, for example, in access control, we are now running into troubles again. The point is that in traditional security models, access control usually relied on on-line servers which needed fast and reliable global communication. That was becoming true in the Internet and other networks but at the same time we are developing new networks that again have limited capacity, poor coverage, unreliable links and nodes.