Abstract: An information processing device that receives, from another information processing device, a communication message generated based on recency information and control data, includes: a recency information generation unit that generates the recency information; and a recency information management unit that extracts the recency information from the received communication message.

Abstract: An arithmetic device includes a communication unit configured to receive a message including a reception authentication code, a storage unit configured to store a key, and a message verification unit configured to generate a generation authentication code, using the key, for data to be verified including data excluding at least the reception authentication code from the message received by the communication unit, a first counter value updated in response to reception of the message and initialized at a time when an abnormality regarding transmission/reception of the message occurs, and a second counter value updated at a time when the abnormality occurs, and to verify the message according to whether the reception authentication code and the generation authentication code match.

Abstract: An information processing device that receives, from another information processing device, a communication message generated based on recency information and control data, includes: a recency information generation unit that generates the recency information; and a recency information management unit that extracts the recency information from the received communication message.