ENCRYPTED DATA COMMUNICATION UNIT AND ENCRYPTED DATA COMMUNICATION METHOD

摘要

PROBLEM TO BE SOLVED: To prevent key data from leaking through communication an external unit illegally connected. SOLUTION: The encrypted data communication unit 20 of this invention uses key data K stored in advance in a memory 23 to communicate data including encrypted data with a prescribed device 10. A command sequence memory 27 stores, in advance, a sequence of command data sent to or received from the prescribed device 10 in normal communication. A discrimination means 26 discriminates whether or not the command data sent to or received from an external device are in accordance with the sequence stored in the command sequence memory 27. A key data delete means 28 deletes the key data K stored in the memory 23 when the means 26 discriminates that the command data sent to or received from the external device are not in accordance with the sequence stored in the command sequence memory 27.