FUJITSU. 68, 4, p. 59-65 07, 2017 59 あ ら ま し 2016 1 IC 4 IC PKI Public Key Infrastructure IC Abstract In January 2016, the Social Security and Tax Number System (My Number System) was inaugurated and issuance of Individual Number Cards to applicants started as well. An Individual Number Card is an IC card equipped with both contact and contactless external interfaces and information including the