INFORMATION PROCESSING DEVICE, INFORMATION PROCESSING METHOD, AND INFORMATION PROCESSING SYSTEM

PROBLEM TO BE SOLVED: To prevent eavesdropping by a third party when a key is updated without performing complicated processing.SOLUTION: An IC card 30 comprises: a non-volatile memory 35 for storing a first key; a communication unit 31 for receiving encrypted data which is data of a second key, which is a new key, encrypted by use of a key identical to the first key; and a CPU 32 for performing control to decrypt the received encrypted data to the second key by use of the first key stored in the non-volatile memory 35, and to rewrite the first key stored in the non-volatile memory 35 to the second key.