Method for preventing illegitimate use of chip cards

• US 20040112965A1
• Filed: 12/18/2001
• Published: 06/17/2004
• Est. Priority Date: 05/21/1999
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Schepers, Jorg
• Granted Patent: US 7,025,278 B2
• Time in Patent Office: Days
• US Class Current: 235/492
• CPC Class Codes: G06K 19/073 Special arrangements for circuits, e.g. for protecting identification code in memory protection against unauthorised use of computer memory G06F12/14
• CPC Class Codes: G06K 19/07372 by detecting tampering with the circuit

Abstract

In order to detect attempted interventions in the vicinity of a smart card, a sensor hierarchy is used. Abnormal operating states are first detected by less sensitive sensors that are connected upstream and which then activate sensors which are connected downstream and have a relatively high degree of sensitivity, or increase the sensitivity of sensors connected downstream.

Claims

1. A method for detecting an attempt at manipulatory intervention in a smart card, which comprises the steps of:

using various sensors for detecting abnormal operating states;

sensing an occurrence of an abnormal operating state by some of the sensors; and

activating the sensors with a relatively high degree of sensitivity relative to an overall sensitivity of the sensors as a group after the abnormal operating state has been sensed.

2. The method according to claim 1, which comprises providing the sensors with different degrees of sensitivity and successively more sensitive sensors are activated after the abnormal operating state has been sensed.

3. The method according to claim 1, which comprises providing the sensors with sensitivities which can be set at different degrees, and the sensors which are used are successively switched to a higher sensitization state after the abnormal operating state has been sensed.