| 摘要 |
PROBLEM TO BE SOLVED: To compensate the balance of the IC card 11 containing electronic coins in case of its breakage. SOLUTION: The card 11 and a compensation institution 13 share secret information; when coin information Mi+1 is generated in the card 11 as a result of payment, last disturbance information hMi-1Mi, and Mi+1 and S are inputted to a unidirectional function arithmetic part 14 to obtain disturbance information hMiMi+1, which is recorded in a recording part 16 of a personal computer together with Mi+1 and also stored in the storage part 12 of the card 11. If the card 11 is broken, the information in the recording part 16 is all supplied to the institution 13, which inputs Mi+1, hMi-1Mi, and S to a unidirectional function arithmetic part 24 in order according to the old information; and its output h(hMi-1Mi, Mi+1, S) and compared with the inputted hMiMi+1 and when they completely match each other, the amount of money determined by from M1 to Mi+1 is compensated. |
