Cracking the Credit Card Code

Credit cards are everywhere, almost everyone around us has one or more than one. This post will show you how to crack the 16-digit code on your credit card.

4417 1234 5678 9113
4 - the first digit is the Major Industry Identifier.It designates the category of the entity which issued the card.
1 and 2 are airlines
3 is Travel and Entertainment
4 and 5 are Banking and Financial
6 is Merchandizing and Baking
7 is Petroleum
8 is Telecommunications
9 is National assignment

The first 6 digits are the Issuer Identification Number. It will identify the institution that issued the card.
Visa: 4xxxxx
Mastercard: 51xxxx - 55xxxx
Discover:6011xx, 644xxx, 65xxxx
Amex: 34xxxx, 37xxxx

Cards can be looked up by their IIN (Issuer Identification Number).
A card that starts with 376211 is a Singapore Airlines Krisflyer
American Express Gold Card.
529962 designates a pre-paid Much-Music MasterCard.

The 7th and following digits, excluding the final digit, are the person`s account number. This leaves a trillion possible combinations if the maximum of 12 digits is used. Many cards only use 9 digits.

3 The final digit is the check digit or checksum. It is used to validate the credit card number using the Luhn algorithm.

How to validate a credit card with your mind

Take the above number (or any credit card number)
4417 1234 5678 9113 (And double every other digit from the left)
*   *   *  *    *  *    *  *
2  2   2  2   2  2   2  2
=
8  2   2  6  10 14 18 2
Add these new digits to undoubled ones
  4  7   2  4   6   8  1   3


All double digit numbers are added as a sum of their digits,so 14 becomes 1 + 4

8+4+2+7 + 2+2+6+4 + 1+0+6+1+4+8 + 1+8+1+2+3
=70

If the final sum is divisible by 10,then the credit card number is valid.
If it`s not divisible by 10, the number is invalid or fake.