If you lost your ATM card on the street, how easy would it be for someone to correctly guess your PIN and proceed to clean out your savings account? Quite easy, according to data scientist Nick Berry, founder of Data Genetics, a Seattle technology consultancy.
Berry analyzed passwords from previously released and exposed tables and security breaches, filtering the results to just those that were exactly four digits long [0-9]. There are 10,000 possible combinations that the digits 0-9 can be arranged into to form a four-digit code. Berry analyzed those to find which are the least and most predictable. He speculates that, if users select a four-digit password for an online account or other web site, it's not a stretch to use the same number for their four-digit bank PIN codes.
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 were 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 "password" and "123456" topped the list.)
Berry says 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.
We don't like hard-to-remember numbers and "no one thinks their wallet will get stolen," Berry says.
Many of the commonly used passwords are, of course, dates: birthdays, anniversaries, year of birth, 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.