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Secure data interchange system erasing a card memory upon an invalid response

  • US 5,239,166 A
  • Filed: 09/09/1991
  • Issued: 08/24/1993
  • Est. Priority Date: 01/17/1989
  • Status: Expired due to Fees
First Claim
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1. An electronic card for use in a secure data interchange system having a terminal adapted to receive and communicate with said electronic card, said card having means for communicating with said terminal and having a memory for storing program algorithms and data therein including valid terminal verification data and valid user identification request data;

  • said electronic card comprising;

    means for monitoring, for a predetermined period of time, immediately following insertion of said card in said terminal, an output from said terminal for a terminal verification message and being operable to erase said memory when said terminal verification message is not received within said predetermined period of time and being responsive to said terminal verification message received within said predetermined period of time, by comparing said received terminal verification message to said stored valid terminal verification message and being operable to erase said memory when said received terminal verification message is not valid; and

    means for monitoring, following receipt of a valid terminal verification message, the output from said terminal for a user identification request and being responsive to said user identification request by comparing said received user identification request to said stored valid user identification request and being operable to erase said memory when said user identification request is not valid and being operable to erase said memory when said received request is an attempt to read data from said memory before receipt of said valid user identification request.

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