Patent ID: 8832451

Claim:
A source authentication method which is performed with respect to a transmission packet on a message transmission side, comprising: generating a first hash value of a first message by applying a first hash function using a key value; generating the transmission packet including the first hash value; generating a next packet including the first message; and embedding the key value in the transmission packet or the next packet, wherein the key value is one of at least one key value generated in advance by applying a second hash function, and the first message is not included in a same packet containing the first hash value, wherein the second hash function is a one-way hash function, and the key value is one of at least one key value generated by applying the one-way hash function before generating an initial transmission packet, and wherein the key value used in the generation of the first hash value is included in a 2n th transmission packet after the initial packet is transmitted, wherein n is a natural number, one different key value is selected from among the key values generated in advance as the key value used in the generation of the first hash value after the transmission packet including the key value is transmitted, and the one different key value is selected in the opposite order to that in which the key values are generated.