An apparatus for a vehicle-to-everything (V2X) service establishes a secure session with a V2X server by using a transport layer security (TLS) handshake on the basis of an X.509 certificate of the V2X server. The apparatus generates a signed V2X message having a digital signature generated on the basis of a pseudonym certificate. The apparatus encodes the signed V2X message on the basis of the X.509 certificate.