when a special relationship is present between ic card owners , authority of one of the ic card owners cannot be easily given to the other owner of the ic card . however , an ic card of a second owner can issue a public key certificate of the ic card of a first owner so that the ic card of the first owner can be recognized as a child card of the ic card of the second owner . thus , the first generation card authenticated by a route authentication station is set as an ancestor which can generate a descendent card which receives the authentication . by checking which parent card has issued the public key authentication owned by the child card , it is possible to given the authority of the parent card to the child card .