UK start-up tackles PIN fraud with patterns

We all know that the weakest link in almost any security system is the user. We puny humans are prone to errors, and so we tend to write down complicated passwords, or choose ones which are stupidly easy to guess.

Same with PINs. How many of you (be honest now) use your birth year? A PIN also stays the same all the time. But no one wants to carry around a token to generate a new PIN each time. People are also rubbish at remembering numbers (which is why a reasonable portion of us even write down our PINs. You probably know someone who does this).

Factor in proper criminal types doing a spot of shoulder surfing while you're at the cashpoint, and really it is close to being a miracle that all of us don't have cash drained from our banks every day.

Stephen Howes, director and CEO of GrIDsure, a Cambridgeshire based start-up, reckons he has the solution.

"People are very good at remembering patterns," he says. So he and his fellow inventor, Jonathan Craymer, came up with a simple scheme. Take a grid filled with pseudo-randomly generated numbers and choose a pattern. It could be anything from four squares in a row, to a tick shape, to the beginning of a zigzag.

You remember your pattern, not a PIN. Each time you need to authenticate yourself, a terminal (or the screen of your computer/mobile phone/whatever) will show you a grid. You read off the numbers that match your pattern and enter them on the normal keypad. Each time you see the grid, the numbers are different, so even if you are shoulder surfed, it doesn't matter.

"For a five by five grid, and a four cell pattern, you have 25⁴ possible patterns. That's 390,625 possible arrangements, compared to the 10,000 possible combinations of four digits in a traditional PIN," he says.

Howes add that the numbers are also repeated, so even if someone did see the number you entered, it would be very hard for them to work out which set of digits you were reading off.

Usability testing run by Angela Sasse, professor of human centred technology at UCL, suggests the system is easy to grasp and the pattern is easier for people to remember than a normal PIN, especially if there are long periods between uses. After 12 weeks, a group of test subjects were asked to use the pattern they had selected. More than 90 per cent remembered it first go.

She said the system "has the potential to offer good usability and increased security at the same time".

GrIDsure is an IP-based firm with some "support" from Price WaterhouseCoopers. It has a global patent application in, and says it is very sure it is not infringing anyone else's ideas. The technology is available "as a strict licensing model. We're not competing with chip and PIN, but we could make it a lot more secure", Howes says.

The firm is working with third party software developers to build the actual solutions, and is in the early stages of setting up a certification system.

The technology has plenty of applications, which is reflected in the range of people GrIDsure is talking to. It is in talks with local authorities (South Lakeland district council has just started running a pilot scheme), the Cabinet Office, and various "very large" software vendors. It's also had interest from a Canadian healthcare organisation which wants to use the technology to authenticate emails.

Howes notes that it could even be used with children, because it doesn't require literacy. He suggests it would make a sensible alternative to fingerprinting kids for library access at school, and for that alone, we salute him. ®