A data communication method of a V2X communication device, the data communication method comprising: receiving, a first authentication token, AT, of the V2X communication device for security authentication, from a discovery authenticate server; transmitting, to an external V2X communication device, a device discovery message based on an WAVE Short Message, WSM, wherein the device discovery message comprises the first AT; receiving, a discovery response message regarding the device discovery message from the external V2X communication device, wherein the discovery response message comprises a second AT of the external V2X communication device for the security authentication; performing the security authentication on the second AT included in the discovery response message with the discovery authenticate server; and adding the second AT of the external V2X communication device to a trust device authentication token list, TDAL, of the V2X communication device, based on the security authentication on the second AT, wherein based on the second AT of the external V2X communication device being added to the TDAL, a device discovery on the external V2X communication device is performed by using Discovered AT_INFO generated based on the TDAL, wherein the device discovery message comprises a Identification for the device discovery message, a first time slot field, a first Length field, a data field related to the device discovery message, and a field of the Discovered AT_INFO, and wherein the discovery response message comprises a Identification for the device response message, a second time slot field, a second Length field, and a data field related to the device response message. receiving, a first authentication token, AT, of the V2X communication device for security authentication, from a discovery authenticate server; transmitting, to an external V2X communication device, a device discovery message based on an WAVE Short Message, WSM, wherein the device discovery message comprises the first AT; receiving, a discovery response message regarding the device discovery message from the external V2X communication device, wherein the discovery response message comprises a second AT of the external V2X communication device for the security authentication; performing the security authentication on the second AT included in the discovery response message with the discovery authenticate server; and adding the second AT of the external V2X communication device to a trust device authentication token list, TDAL, of the V2X communication device, based on the security authentication on the second AT, wherein based on the second AT of the external V2X communication device being added to the TDAL, a device discovery on the external V2X communication device is performed by using Discovered AT_INFO generated based on the TDAL, wherein the device discovery message comprises a Identification for the device discovery message, a first time slot field, a first Length field, a data field related to the device discovery message, and a field of the Discovered AT_INFO, and wherein the discovery response message comprises a Identification for the device response message, a second time slot field, a second Length field, and a data field related to the device response message. <EOS>