Archive for the ‘Uncategorized’ Category


Posted: July 1, 2012 in Uncategorized

Hello Defcon, 
I will be coming to you one day! ūüôā


Need a team

Posted: July 1, 2012 in Uncategorized

Damnn…. I need a better team. Each of them should specialize in one thing so that I don’t need to go around and check what they are doing. But where can I find those people? :((

Of the 16¬†numbers¬†you¬†see in the¬†Visa¬†or¬†MasterCard¬†credit¬†card,¬†the first¬†6 digits¬†is the”issuer¬†identifier”,¬†ie¬†the credit¬†card type¬†code.¬†If the¬†sixth¬†digit¬†is preceded¬†by 4,¬†meaning the credit¬†card¬†type is Visa.¬†However,¬†if the¬†six¬†digits¬†are¬†preceded by¬†5, meaning¬†the creditcard¬†type is MasterCard.¬†Next,¬†a¬†last digit of¬†16 digit¬†numbers on¬†the credit¬†card¬†serves¬†as a”check¬†digit”,¬†whose function is¬†only¬†for¬†the validation¬†checks¬†credit¬†card numbers.¬†Since the¬†initial¬†6 digits¬†and¬†last¬†digit¬†1¬†is¬†already¬†a¬†significance,¬†meaning¬†remaining¬†9 digits¬†in the middle¬†that serves¬†as an¬†“account number”.¬†Therefore¬†there were 10¬†possible¬†numbers(from¬†the digits 0¬†to 9)¬†which¬†can be inserted¬†into¬†each¬†digit¬†from¬†9 digit¬†“account number” is,¬†then the¬†resulting¬†combination¬†of¬†9 digits¬†amounted to¬†1 billion¬†possible¬†numbers¬†foreach type¬†of credit¬†card¬†(visa¬†or¬†MasterCard).¬†The¬†algorithm¬†used¬†to¬†generate¬†a row of¬†16 points¬†for¬†credit¬†card¬†numbers¬†is called¬†an algorithm¬†“Luhn”¬†or¬†“Mod¬†10”.¬†Back in¬†1954,Hans¬†Luhn¬†of¬†IBM¬†is the¬†person¬†who first¬†proposed the¬†application of¬†algorithms¬†to determine¬†the validity of¬†a¬†credit¬†card number.¬†The workings of¬†a¬†simple¬†algorithm¬†(butexcellent)¬†are as¬†follows:
1.   Starting at the first digit, multiply two-digit occupies all odd numbers, so as a whole will have 8 digits that you multiply by 2, the digit to 1, 3, 5, 7, 9, 11, 13, and 15.
 2.  If the square 2 result in a number of two digits (10, 12, 14, 16, or 18), the sum of each digit numbers to produce a new digit, so that the results of the first and second steps are fixed in the form 8 the number.
3.   The next step, replace all the numbers (credit card number) located in the odd positiondigits with 8 new figures, to generate a new row of 16 points.
4.   The final step, add up to-16 figure.If the sum is a multiple of 10, meaning the credit card number is valid, and conversely, if nota multiple of 10, meaning the credit card number is invalid. Below I give examples of actualcalculations:
As you can see in the picture above this, the credit card number is 4552 7204 1234 5678,because it begins with 4, it means the card type Visa. Now we do the calculations.
If¬†you have¬†carefully¬†calculated, it will be¬†seen that¬†the final count¬†is 61, which is¬†NOT amultiple of 10¬†numbers,¬†so that¬†we can be sure¬†that¬†the credit¬†card number¬†is¬†invalid.¬†If¬†the “check¬†digit”¬†in¬†the example¬†is¬†not 8,¬†but¬†7, then¬†the¬†algorithm,¬†the credit¬†card number¬†will¬†bevalid,¬†because the total¬†sum¬†will be changed to¬†60,¬†a number is¬†a multiple of 10.¬†Here’s another example:
Once again, do the calculations according to Luhn algorithm above for MasterCard creditcard number is 5490 1234 5678 9123.
As you can count itself, the total sum is 65, so the credit card number is invalid, because thenumber 65 is NOT a multiple of 10.
If only,¬†“check¬†digit”¬†credit¬†cards¬†instead of 3,¬†but¬†8, then¬†sum¬†the results¬†would be 70,¬†which is a¬†multiple of 10,¬†so that¬†the credit¬†card number¬†will¬†be¬†valid¬†(the¬†algorithm).¬†Validunderstanding¬†of the above is¬†valid¬†mathematical¬†calculation,¬†it does not mean¬†that creditcard number¬†is absolutely certain¬†that¬†the original¬†credit¬†card number.
Due¬†to¬†credit¬†card¬†checks¬†(at the time of¬†online transactions,¬†for example) is required¬†notonly a¬†credit¬†card number¬†only,¬†but¬†also “expiry¬†date”,¬†and¬†“card¬†security code”¬†or collectively, the¬†CVV¬†(Card¬†Verification¬†Value)¬†or¬†CVC¬†(Card¬†Verification¬†code)¬†which is the¬†last 3 digits¬†behind¬†the credit¬†card.
PS:¬†For¬†American Express credit¬†card,¬†the number of¬†digits¬†instead of 16,¬†but¬†only¬†15, andalways begin¬†with 34¬†or 37¬†for¬†the first¬†2 digits.As for the¬†“account number” it¬†only¬†has a¬†length of 8¬†digits,¬†not 9¬†digits¬†such as¬†credit¬†cardtype¬†Visa¬†or¬†MasterCard.

The Conscience Of A HACKER

Posted: November 13, 2011 in Uncategorized

The Conscience Of A HACKER