IC-card system.

摘要

A data processing terminal device is on-line connected to a host computer and records on journal paper journal data obtained as a result of communication with the host computer. Data is encrypted, and encrypted data is exchanged between the terminal device and the host computer. The encrypted journal data is printed together with the normal journal data on the journal paper. By comparing the journal data with its encrypted data, journal data alteration can be easily detected. The encrypted journal data transmitted from the host computer is decrypted in an IC card. The decrypted data is printed on paper, and the modified data of the journal data is written in an IC card.