Information processor, mobile body apparatus, and communication system

An information processor comprising:

• a memory storing a program, and
• at least one processor configured to execute the program to perform operations comprising:
• protecting at least a portion of a first communication in which a frame is transmitted or received, wherein the frame includes first packet data of multiple lines, the frame includes a packet header and a packet data payload, and the packet data payload is separated into an extended packet header and a legacy payload including the first packet data;
• performing an arithmetic operation of a first message authentication code that protects a portion or an entirety of the first packet data, on a basis of first communication message authentication policy information indicating which first communication message authentication policy is selected from alternatives including a first message authentication policy, a second message authentication policy, a third message authentication policy, and a fourth message authentication policy, wherein
• the first communication message authentication policy information is stored in the extended packet header within the packet data payload,
• the first message authentication policy is a policy that applies the protection by the first message authentication code to the entirety of the first packet data,
• the second message authentication policy is a policy that excludes the protection by the first message authentication code for a portion of the first packet data in a line vertical direction,
• the third message authentication policy is a policy that excludes the protection by the first message authentication code for a portion of the first packet data in a line horizontal direction, and
• the fourth message authentication policy is a policy that excludes the protection by the first message authentication code for the entirety of the first packet data;
• executing an arithmetic operation of at least one of a second message authentication code or CRC, which protects at least a portion of second communication;
• and
• transmitting or receiving a message group in the second communication, wherein
• a final message in the message group includes information indicating whether or not the arithmetic operation of at least one of the second message authentication code or the CRC can be completed.

A non-transitory computer readable medium storing a program, the program being executable by at least one processor to perform operations comprising:

• protecting at least a portion of a first communication in which a frame is transmitted or received, wherein the frame includes first packet data of multiple lines, the frame includes a packet header and a packet data payload, and the packet data payload is separated into an extended packet header and a legacy payload including the first packet data;
• performing an arithmetic operation of a first message authentication code that protects a portion or an entirety of the first packet data, on a basis of first communication message authentication policy information indicating which first communication message authentication policy is selected from alternatives including a first message authentication policy, a second message authentication policy, a third message authentication policy, and a fourth message authentication policy, wherein
• the first communication message authentication policy information is stored in the extended packet header within the packet data payload,
• the first message authentication policy is a policy that applies the protection by the first message authentication code to the entirety of the first packet data,
• the second message authentication policy is a policy that excludes the protection by the first message authentication code for a portion of the first packet data in a line vertical direction,
• the third message authentication policy is a policy that excludes the protection by the first message authentication code for a portion of the first packet data in a line horizontal direction, and
• the fourth message authentication policy is a policy that excludes the protection by the first message authentication code for the entirety of the first packet data;
• storing, in a functional register, information related to an upper limit of a data amount that can be held for an arithmetic operation of a second message authentication code that protects at least a portion of a second communication;
• and
• verifying the second message authentication code for a data group within a range not exceeding the upper limit of the data amount;
• and
• inhibiting, by the at least one processor, execution of processing of write data, read data, or decryption in response to successful verification of the second message authentication code.

A non-transitory computer readable medium storing a program, the program being executable by at least one processor to perform operations comprising:

• protecting at least a portion of a first communication in which a frame is transmitted or received, wherein the frame includes first packet data of multiple lines, the frame includes a packet header and a packet data payload, and the packet data payload is separated into an extended packet header and a legacy payload including the first packet data;
• performing an arithmetic operation of a first message authentication code that protects a portion or an entirety of the first packet data, on a basis of first communication message authentication policy information indicating which first communication message authentication policy is selected from alternatives including a first message authentication policy, a second message authentication policy, a third message authentication policy, and a fourth message authentication policy, wherein
• the first communication message authentication policy information is stored in the extended packet header within the packet data payload,
• the first message authentication policy is a policy that applies the protection by the first message authentication code to the entirety of the first packet data,
• the second message authentication policy is a policy that excludes the protection by the first message authentication code for a portion of the first packet data in a line vertical direction,
• the third message authentication policy is a policy that excludes the protection by the first message authentication code for a portion of the first packet data in a line horizontal direction, and
• the fourth message authentication policy is a policy that excludes the protection by the first message authentication code for the entirety of the first packet data;
• executing an arithmetic operation of at least one of a second message authentication code or CRC, which protects at least a portion of second communication;
• and
• transmitting or receiving a message group in the second communication, wherein
• a final message in the message group includes information indicating whether or not the arithmetic operation of at least one of the second message authentication code or the CRC can be completed.