Mutual authentication is performed. A reader/writer (R/W) transmits to an IC card a code C.sub.1 that is a random number R.sub.A encrypted using a key K.sub.B. The IC card decrypts the code C.sub.1 into plain text M.sub.1 using the key K.sub.B. The IC card transmits to the R/W a code C.sub.2 that is...http://www.google.com.hk/patents/US6073236?utm_source=gb-gplus-share專利 US6073236 - Authentication method, communication method, and information processing apparatus
