The present invention uses a group key management scheme for admission control while enabling various conventional approaches toward establishing peer-to-peer security. Various embodiments of the invention can provide peer-to-peer confidentiality and authenticity, such that other parties, such as group members, can not understand communications not intended for them. A group key may be used in combination with known unicast security protocols to establish, implicitly or explicitly, proof of group membership together with bi-lateral secure communication.