Transaction authentication system

A transaction authentication system comprising:

• terminal means including:
• first processing means;
• and
• a card reader/writer;
• a first memory means;
• and
• an integrated circuit card which is detachably loaded into said card reader/writer, said integrated circuit card including:
• second processing means:
• and
• second memory means,
• said terminal means supplying at least a transaction data which is related to a transaction and a designated storage region in said second memory means for storing the transaction data to said integrated circuit card when said integrated circuit card makes an access to a service via said terminal means,
• said second processing means of said integrated circuit card writing the transaction data received from said terminal means in the designated storage region of said second memory means and generating a verified data which is renewed every time the transaction data is written into said second memory, said verified data having a value in conformance with a predetermined generating algorithm using the verified data stored previously in said second memory, said verified data being stored in said second memory means and also supplied to said terminal means,
• said first processing means of said terminal means generating transaction historical information which includes at least the designated storage region, the transaction data and the verified data, and storing the transaction historical information in said first memory means, thereby a transaction being authenticated from a correspondence of the verified data stored in said first memory means and the verified data stored in said second memory means.