A combined motion detection and access control method comprising: receiving, from one of a multiplicity of motion detectors deployed within a premises, an indication of motion detection within the premises; ascertaining an indication of an area of said premises within which a motion was detected, by ascertaining which one of the multiplicity of motion detectors has detected the motion; responsive to said ascertaining said area of said premises within which said motion was detected, broadcasting, within said area, within which said motion was detected, an encoded area identification of said area within which said motion was detected; receiving, by a mobile transceiver (130, 230) associated with an individual, said encoded area identification, of said area within which said motion was detected; responsive to said receiving said encoded area identification of said area within which said motion was detected, attesting to a presence of said individual in said area of said premises encoded in said encoded area identification by broadcasting, by said mobile transceiver (130, 230) associated with said individual, an encoded identification of said individual together with said encoded area identification of said area within which said motion was detected; receiving said encoded identification of said individual together with said encoded area identification of said area within which said motion was detected; and responsive to said receiving said encoded identification of said individual together with said encoded area identification, of said area within which said motion was detected, ascertaining whether said individual identified by the encoded identification is allowed access to said area of said premises encoded in said encoded area identification within which said motion was detected. receiving, from one of a multiplicity of motion detectors deployed within a premises, an indication of motion detection within the premises; ascertaining an indication of an area of said premises within which a motion was detected, by ascertaining which one of the multiplicity of motion detectors has detected the motion; responsive to said ascertaining said area of said premises within which said motion was detected, broadcasting, within said area, within which said motion was detected, an encoded area identification of said area within which said motion was detected; receiving, by a mobile transceiver (130, 230) associated with an individual, said encoded area identification, of said area within which said motion was detected; responsive to said receiving said encoded area identification of said area within which said motion was detected, attesting to a presence of said individual in said area of said premises encoded in said encoded area identification by broadcasting, by said mobile transceiver (130, 230) associated with said individual, an encoded identification of said individual together with said encoded area identification of said area within which said motion was detected; receiving said encoded identification of said individual together with said encoded area identification of said area within which said motion was detected; and responsive to said receiving said encoded identification of said individual together with said encoded area identification, of said area within which said motion was detected, ascertaining whether said individual identified by the encoded identification is allowed access to said area of said premises encoded in said encoded area identification within which said motion was detected.