## Saturday, August 4, 2018

### “All credit card PIN numbers in the World leaked”

From DataGenetics:

PIN Analysis
A good friend of mine, Ian, recently forwarded me an internet joke. The headline was something like:
“All credit card PIN numbers
in the World leaked”
The body of the message simply said 0000 0001 0002 0003 0004

Ian’s messages made me chuckle. Then, later the same day, I read this XKCD cartoon. The merging of these two humorous topics created the seed for this article.
What is the least common PIN number?
There are 10,000 possible combinations that the digits 0-9 can be arranged to form a 4-digit pin code. Out of these ten thousand codes, which is the least commonly used?

Which of these pin codes is the least predictable?
Which of these pin codes is the most predictable?

If you were given the task of trying to crack a random credit card by repeatedly trying PIN codes, what order should you try guessing to maximize your chances of selecting the correct number in the shortest time?

If you had to make predication about what the least commonly used 4-digit PIN is, what would be your guess?

This tangentially relates to the XKCD cartoon. In Randall’s cartoon, the perpetrator’s plan backfired because his selected license plate was so unique that it was very memorable. What is the least memorable license plate? Ask any spy you know (snigger) what the best way to blend into a crowd is. Their answer will be not stand out, to appear “normal”, and not be notable in any way.

If you had to make predication about what the least commonly used 4-digit PIN is, what would be your guess?

People are notoriously bad at generating random passwords. I hope this article will scare you into being a little more careful in how you select your next PIN number.
Are you curious about what the least commonly used PIN number might be?