Scientists perfecting picture passwords

Researchers at Newcastle University have developed graphical passwords for mobile devices, and hope to expand the uses of the software.

Computer scientists from Newcastle University have developed software that lets the user draw pictures as an alternative to remembering strings of letters and numbers.

Jeff Yan, a lecturer at Newcastle University, said: "Many people find it difficult to remember a password so choose words that are easy to remember and therefore more susceptible to hackers."

The researchers - Yan, with Phd student Paul Dunphy - took as their starting point the Draw a Secret Scheme (DAS), initially developed by researchers from AT&T Labs, Bell Labs and New York University. The scheme focused on the design and analysis of graphical passwords.

In DAS, the user draws an image, which is then encoded as an ordered sequence of cells. The software recalls the strokes, along with the number of times the pen is lifted.

By superimposing a background over the blank DAS grid, the Newcastle University researchers have created a system called BDAS: Background Draw a Secret. This helps users remember where they began the drawing they are using as a password.

For example, if a person chooses a flower background and then draws a butterfly as their secret password image onto it, they can more easily remember where they began on the grid and the order of their pen strokes. As in other biometric recognition systems, the graphical password is recognised from the template that has been created, not from the drawing itself.

Yan said: "Most of us have forgotten a PIN or a password at least once, which is why we tend to make them so easy to guess. However, the human mind has a much greater capacity for remembering images, and it's certainly true that a picture is worth a thousand words in this instance."

Yan will carry out further research into how easily the BDAS system can be used by people who traditionally have difficulty with textual systems, such as those with dyslexia.

Tom Espiner writes for ZDNet UK