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Coding formula for verifying checks and credit cards

  • US 5,754,653 A
  • Filed: 07/26/1995
  • Issued: 05/19/1998
  • Est. Priority Date: 07/26/1995
  • Status: Expired due to Fees
First Claim
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1. A method of verifying that a credit card transaction is being completed by an authorized user of a credit card, comprising the steps of:

  • a. issuing a credit card to a credit card holder with an account;

    b. assigning a security code formula to said credit card holder'"'"'s account and making said formula known to said credit card holder, said formula consisting of two variables, namely;

    (1) a constant, multiple-digit numerical base code, said base code being separated into a first part and a second part;

    (2) one or more arithmetic modes;

    c. upon presentation of said credit card for payment of a transaction, having said credit card holder be informed of a total transaction amount;

    d. requiring said credit card holder to calculate a verification code number which is a mathematical result of performing said arithmetic mode upon the transaction amount and the first part of said base code, and then performing said arithmetic mode or a second arithmetic mode upon the result and the second part of said base code;

    e. requiring said credit card holder to inscribe said verification code number on a transaction slip and to inscribe any single-digit number or numbers to complete an eight-digit entry;

    f. verifying said verification code number by comparing it to the verification code number which would be produced by said security code formula for said account.

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