Why you shouldn't keep birthdates as ATM pins

If your ATM pin code is your birth date, a year in the 1900s, or an obvious numerical sequence, the chances of thieves cracking your password are way higher, according to a new study.

Researchers from the data analysis firm Data Genetics have found that the three most popular combinations -- '1234', '1111', and '0000' -- account for close to 20 per cent of all four-digit passwords.

Every four-digit combination that starts with '19' ranks above the 80th percentile in popularity, with those in the upper -- 1900s coming in the highest, Slate magazine reported.

Also quite common are combinations in which the first two digits are between '01' and '12' and the last two are between '01' and '31'.

So choosing your birthday, your birth year, or a number that might be a lot of other people's birthday or birth year makes your password significantly easier to guess.

On the other end of the scale, the least popular combination -- 8068 -- appears less than 0.001

per cent of the time.

Rounding out the bottom five are '8093', '9629', '6835', and '7637'.

Data Genetics came up with the numbers by analysing a database of 3.4 million stolen passwords that have been made public over the years.

Most of these are passwords for websites.

But by looking specifically at those that comprise exactly four characters, all of which are numerals, the researchers figured they could get a decent proxy for ATM pins as well.

The data also showed that people prefer even numbers to odd, so '2468' ranks higher than '1357'.

Far more passwords start with '1' than any other number.

In a distant second and third are '0' and '2'.

Among seven-digit passwords, the fourth-most popular is '8675309,' which should ring familiar to fans of '80s music.

The 17th-most popular 10-digit password is '3141592654'.

Two-digit sequences with large numerical gaps, such as '29' and '37' were found often among the least popular passwords.