A first infrastructure system device other than a mobile station generates an encryption key and encrypts the encryption key with a first intrakey associated with a first zone that includes a second infrastructure system device other than a mobile station, yielding a first encrypted encryption key. The first intrakey is used only by infrastructure system devices other than a mobile station for encrypting at least the encryption key prior to transport within the first zone. The first infrastructure system device forwards the first encrypted encryption key to the second infrastructure system device.