Selecting a 4 digit pin code is hardly random

There are 10,000 possible pin codes that could be made with four digits (0-9) but what pins we select to use are hardly random:

What he found, he says, was a “staggering lack of imagination” when it comes to selecting passwords. Nearly 11% of the 3.4 million four-digit passwords he analyzed are 1234. The second most popular PIN in is 1111 (6% of passwords), followed by 0000 (2%). (Last year SplashData compiled a list of the most common numerical and word-based passwords and found that the “password” and “123456” topped the list.)

Berry says that a whopping 26.83% of all passwords could be guessed by attempting just 20 combinations of four-digit numbers (see first table). “It’s amazing how predictable people are,” he says…

Many of the commonly used passwords are, of course, dates: birthdays, anniversaries, the year you were born, etc. Indeed, using a year, starting with 19__ helps people remember their code, but it also increases its predictability, Berry says. His analysis shows that every single 19__ combination be found in the top 20% of the dataset…

Somewhat intriguing was #22 on the most common password list: 2580. It seems random, but if you look at a telephone keypad (or ATM keypad) you’ll see those numbers are straight down the middle — yet another sign we’re uncreative and lazy password makers…

The least-used PIN is 8068, Berry found, with just 25 occurrences in the 3.4 million set, which equates to 0.000744%. (See the second table for the least popular passwords.) Why this set of numbers? Berry guesses, “It’s not repeating pattern, it’s not a birthday, it’s not the year Columbus discovered America, it’s not 1776.” At a certain point, these numbers at the bottom of the list are all kind of “the lowest of the low, they’re all noise,” he says.

This is a great example of two things:

1. There are often patterns among supposedly “random” numbers.

2. Humans don’t particularly like to use “random” numbers but instead prefer numbers that are meaningful to them (which corresponds with them being able to remember their codes).

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