The present disclosure relates to a technology for a sensor network, machine-to-machine (M2M) communication, machine-type communication (MTC), and Internet of things (IoT). According to the present disclosure, provided is a method of a first device in a communication system, which includes the operations of: detecting a request of sharing security information of the first device by a second device; registering information about the second device to a service provider; receiving authentication information, which the second device uses for sharing the security information of the first device, from the service provider; and transmitting the authentication information to the second device.