IC card with a stored data change inhibition function

US5148543A · kind A · utility

Assignee

• Kabushiki Kaisha Toshiba · JP

Inventors

• Masuo Tamada · Yokohama, JP
• Tsutomu Tanaka · Nishinomiya, JP

Key dates

• Filing date: Mar 9, 1989
• Grant date: Sep 15, 1992
• Expiry date: Mar 9, 2009

Classification

• Technology area (CPC G): Physics
• CPC primary: G06Q20/35765
• WIPO field: IT methods for management
• WIPO sector: Electrical engineering

Abstract

A nonvolatile memory has an area defining information area for storing area defining information corresponding to user data write areas. Each area defining information contains identification information representing whether a corresponding user data write area is an area in which stored data can be changed in accordance with a command from a keyboard. When a command for changing stored data in one of the user data write areas is supplied from the keyboard, a control element identifies in accordance with the identification information contained in the area defining information corresponding to the user data write area designated by the keyboard whether the designated user data write area is an area in which stored data can be changed. If the designated user data storage area is an area from which stored data cannot be changed, the control element inhibits stored data change processing for the designated user data write area.