Abstract: A system and method distributes keys from a central node to branch nodes in a tree network. The central node and the branch nodes within the tree network are initialized. A root public/private key pair is generated by the central node. Each branch node is loaded with the root public key and a unique branch public/private key pair. A generated group key is distributed to the associated branch nodes. New branch nodes are given the group key after they are associated with the network. Re-keying of the group key throughout the system is done via the central node either at the expiration of the group key, when a node is not sure if a group key is still valid, or when the group key has been compromised.