A system for transmitting and receiving data based on a vehicle network and a method therefor are provided. The method includes generating, by a first hardware security module (HSM), a first session key using a first random number and a first fixed key and, encrypting, by a first electric control unit (ECU), a message using the first session. The method also includes generating, by a second HSM, a second session key using a second random number and a second fixed key, and decrypting, by a second ECU, the message using the second session key.