US Patent 7181614 Method and arrangement in a communication network

The present invention relates to establishing security within an ad hoc network. Such ad hoc networks do not have on-line connections to a particular server for getting desired public keys or certificates, thereby requiring them to create trust relations among their respective nodes wherein some of the nodes have a mutual trust relation to each other, thus constituting a trust group. When a particular candidate node desires to join the trust group, an X-node is identified, being a member of a trust group and having a trust relation with the candidate node. The X-node then certifies the candidate node and establishes and distributes trust relations between the members of the trust group and the candidate node.