| 摘要 |
PROBLEM TO BE SOLVED: To provide a mechanism that prevents data for updating a program from being illegally updated in a nonvolatile memory, as suppressing increase in size of the data for updating the program.SOLUTION: A sub CPU is configured to: receive signature data on a beginning of data for updating a program to be transmitted from a main CPU; encrypt the signature data using a preliminarily stored public key; acquire signature source data including a part of text data on the program to be updated, and store the acquired signature source data in a nonvolatile memory; transfer data including the other part of the text data after the signature data on the data for updating the program to a sub CPU indicated by a CPU specification identifier included in the signature source data, as authenticating the data; and update the program by writing the authenticated data in a prescribed area as authenticating the transferred data. When the update of the data after the signature data on the transferred data for updating the program is normally ended, one part of the text data included in the signature source data stored in the nonvolatile memory is transferred.SELECTED DRAWING: Figure 1 |
