A method and an apparatus for transmitting a message to a plurality of wireless devices that are classified into units of groups are provided. The method includes operations of: (a) determining whether the message is a predetermined message for detecting a device in a network; (b) encrypting the message with one of a plurality of keys respectively corresponding to a plurality of groups according to a determination result obtained in operation (a), each group comprising one or more devices in the network; and (c) transmitting the encrypted message. Accordingly, it is possible to prevent a guest wireless device that is unknown to a user from detecting a home wireless device of the user and controlling the detected home wireless device without authorization from the user.