Kitchens by Riland

One of the most used or rather misused inventions in this modern world is the credit card system. It allows the individuals to shop or dine or stay in exotic hotels without having to carry cash. But with such uses comes the case of credit card security issues. Various standards institutes around the globe have set up certain specifications for numbering the credit card.

The very first digit present on your credit-card represents the MII (The Major Industry Identifier) which indicates the category under which the system that issued the credit card falls. For example if the credit card starts with the number ‘0’ then the card is issued by an ISO or some industry assignments, or if the credit card number starts with ‘4’ or ‘5’ then the credit card is issued by a banking organization. The standards organizations have given a list of the numbers from ‘0’ to ‘9’ and each of these numbers means they have been issued by a different organization.

The first 6 digits of the credit card represent the identifier for the issuer of the credit card. These 6 digits include the MII represented by the first digit of the credit card. The first three digits inclusive of the MII is the issuers identification code for example for American Express the codes start as ‘304’ or ‘307’. Then the remaining three digits are specified by the various standards organizations depending on the type of the credit card or the type of organization of the issuer of the credit card. The digits from 7 to the second last digit of the credit card represent the account number of the individual with the credit card issuing organization. The final digit of the credit card represents the check number. An algorithm is used to arrive at the check number. The algorithm preferred by the standards organizations are the Luhn Algorithm. Luhn Algorithm specifies that if the credit card contains an even number of digits, then the check number is arrived by finding the product of the digits, and if it’s greater than 9 then every odd digit number is doubled and from this 9 is subtracted. Now add all even digits and also the sum achieved by above process. If the result achieved is a multiple of ten, then the card number is valid else invalid. For credit cards with odd number of numbers, then the same procedure is carried out only difference is we double the even digits.