Security file system and method for securing data in a portable data carrier

US4882474A · kind A · utility

Assignees

• American Telephone and Telegraph, Co. · US
• AT&T Information Systems Inc. · US

Inventors

• Ewald C. Anderl · Middletown, US
• Oren Frankel · Ocean Township, US
• Avi Zahavi · Hod HaSharon, IL

Key dates

• Filing date: Feb 5, 1988
• Grant date: Nov 21, 1989
• Expiry date: Feb 5, 2008

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S283/904
• WIPO field: IT methods for management
• WIPO sector: Electrical engineering

Abstract

A security file system for a portable data carrier provides improved security for the data carrier and for data contained in files in the data carrier. Although the data carrier may be embodied to look and feel much like an ordinary credit card, it contains a computer and a programmable memory with operating power and input and output data provided through a contactless interface. In order to provide security for the data carrier, the security file system on the data carrier includes a stored access code for verifying the identity of an individual attempting to access the data carrier, and an appropriate routine for limiting the number of unsuccessful attempts to access the data carrier. The security file system is also configurable to include select ones of multiple stored access codes for enabling the retrieval and modification of data in corresponding select ones of the files. The routine similarly limits the number of unsuccessful attempts to access these files. Operation of the routine is such that a counter in the data carrier is advanced a count each time a code is externally provided to the data carrier. If this external code compares favorably with the stored access code, …