Wallet thieves have chance at guessing card PINs

Powered by SC Magazine
 

British researchers calculate probabilities.

A "competent" thief could guess the four-digit PIN of one payment card in every 11-18 wallets they stole, according to University of Cambridge researchers.

The research [pdf] is based on a mathematical analysis of two leaked datasets combined with the results of a survey of 1177 people.

The research project aimed to estimate the difficulty of guessing a human-chosen four-digit PIN.

Banks and credit card operators often allow customers to change their PIN, rather than use a supplied number.

Of those surveyed by researchers, 1108 had a PIN with exactly four digits. About 63 percent said the PIN was the one supplied by the bank or was one from a previous bank.

Another 21 percent used "pseudo-random" digits extrapolated from a phone number or other identification number.

Of those users found to have "non-random PINs", the highest proportion used a date for their four-digit PIN. Common were birthdays (theirs or a partner's) or an important life event.

In percentage terms, nearly seven percent of those surveyed based their PIN on their birth date.

The researchers said the incidence of birth dates as PINs - and the fact a stolen wallet often contained forms of identification with birth dates - could make "manual guessing by thieves [a] worthwhile" exercise.

"A lost or stolen wallet will be vulnerable up to 8.9 percent of the time in the absence of denied PIN lists, with birthday-based guessing the most effective strategy," the researchers said.

Banks could ameliorate some risk by blacklisting users from setting their PINs as a birthdate or an otherwise common set of numbers, such as 1234, the researchers said.

However, they also noted that "preventing birthday-based guessing requires a move away from customer-chosen PINs entirely".

Copyright © SC Magazine, Australia


Wallet thieves have chance at guessing card PINs
 
 
 
Top Stories
Photos: Microsoft's new Surface 3 tablet
Microsoft has pared down the specs in favour of portability.
 
Is your lawyer smarter than IBM's Watson?
Sparke Helmore CIO Peter Campbell expects machine learning to take a chunk out of law firm profits. But he’s far from downcast.
 
Australia passes data retention into law
Mammoth last-ditch effort by Greens, indies knocked back.
 
 
Sign up to receive iTnews email bulletins
   FOLLOW US...
Latest Comments
Polls
Do you support the Government's data retention scheme?

   |   View results
Yes
  9%
 
No
  91%
TOTAL VOTES: 1428

Vote