Picture this: image-based passwords

MS prototype

Darko Kirovski, cryptography and anti-piracy researcher at Microsoft, last week showed the press a prototype of an image-based password system at the software giant's offices in Mountain View, California.

He clicked on a number of points on a screen emblazoned with the flags of different countries which, he explained, represented a password which users can remember more easily than a text string, but is harder for crackers to break. Users would need only to recall where and in what order they clicked on the images on display.

There's little doubt that users frequently pick insecure default passwords (a recent study discovered 50 per cent base passwords on the name of a family member, partner or a pet while 30 per cent choose a pop idol or sporting hero). Ethical hackers and security consultants tell us weak or default passwords are a major security risk.

But are picture-based passwords any more secure than their text-based alternative?

For one thing, the electronic representation of a series of image selections has to be stored somewhere, and it isn't too hard to imagine someone coming up with a Lopht crack-style utility to break the code.

Implementation is crucial, and any image-based system would be more complex than a text-based system, creating more scope for sloppy coders to make a hash of it.

Neil Barrett, technical director at Information Risk Management (IRM), a security consultancy, said an image-based password system may seem like a good idea but the "devil is in the detail".

IRM has set up a system for children to access a child protection Web site run by the NSPCC (National Society for the Prevention of Cruelty to Children) using an easy-to-use picture-based password system.

Despite this, Barrett is against more widespread use of picture-password technology; he argues that educating users to use strong text-based passwords is a better solution.

Experience shows that would-be crackers often find passwords to user PCs through one of three techniques: dictionary attacks, finding notes on wish someone has written their password and 'shoulder surfing'.

Barrett, who tells us he spent months learning to work out passwords using shoulder surfing, said image-based passwords might make easier to do this.

That's because it is easier to look at mouse movements on a screen than what a user types in, he told us. ®

Sponsored: How to determine if cloud backup is right for your servers