Title:
METHOD FOR CHECKING SMART CARD AND CIRCUIT NETWORK
Document Type and Number:
Japanese Patent JP3516465
Kind Code:
B2
Abstract:
PURPOSE: To provide a method and a circuit network for checking a smart card for sufficiently preventing an illegal means.
CONSTITUTION: A prepaid smart card 12 for purchasing a service from for example, a public telephone includes a memory 18 for a value unit, and those value units are withdrawn according to the purchased service, and the smart card is marked with 'consumed'. The smart card 12 is provided with a test code circuit 16, and response data are generated according to a secret algorithm from an applied test word. Therefore, at the time of using the smart card 12, whether or not it is valid is checked. The illegality of using the valid smart card having the test code circuit 16 by combining it with another operable memory may be planned. The algorithm of the test code circuit 16 is deformed dependently of the content of the memory 18 of the valid smart card 12, and the smart card 12 is checked by using the test code circuit at least after the value units are withdrawn so that the illegality can be prevented. Thus, the illegal usage of an outside memory can be invalidated immediately.
Inventors:
Armbrust, Dirk
Brechtel, Holger
Timm, Volker
Brechtel, Holger
Timm, Volker
Application Number:
JP14227293A
Publication Date:
April 05, 2004
Filing Date:
June 14, 1993
Export Citation:
Assignee:
PHILIPS ELECTRON NV
International Classes:
G06K19/07; G06F21/12; G06F21/14; G06K19/073; G07F7/02; G07F7/08; G07F7/10; G07F7/12; H04M17/00; (IPC1-7): G06K19/07; G06K19/073
Attorney, Agent or Firm:
杉村 興作 （外４名）
Previous Patent: FRONT COVER FOR MOTORCYCLE
Next Patent: ILLUMINATOR AND LIQUID CRYSTAL DISPLAY DEVICE
Next Patent: ILLUMINATOR AND LIQUID CRYSTAL DISPLAY DEVICE