Digitally Scanned Signatures – Can They Be Forged?
18 April 2007
Nazia has produced fantastic work and her project is rightly creating a lot of interest.
”We traditionally guard our signature almost as a badge of honour. It expresses our identity and gives us a useful defence against fraud.
But research at the University of Derby has uncovered alarming evidence that digital signatures which now feature on millions of UK documents such as our driving licences and passports differ from the signatures we would write with a pen – opening up possibilities of fraud.
Final Year BSc Forensic Science student Nazia Mehrban and Dr Ian Turner, University Lecturer in Forensic Science and Biology, explored 150 signatures created with ballpoint, rollerball and fountain pen inks, and sought variations between these and digital versions of the signatures generated on a flatbed scanner..
There were many reported variations, and in one example alone, using forensic signature identification principles, a digital signature differed from the original signature in SIX different ways:
- Details of irregularity of stroke caused by pooling of ink cannot be seen clearly in the digitally scanned signature.
- Although pooling of ink is seen in the digital scan, the colour contrast is much greater in the original version, and therefore clearer.
- Ink spread detail is lost to make the full-stop appear much more rounded in the scanned copy.
- Details of ink spread caused by pooling of ink are not seen in the digital version.
- A slight hook is seen at the beginning of the stroke in the original signature. This feature appears blurred and rounded in the scanned copy.
- Slight ink spread detail is lost in the digital signature.
Nazia, 25, from Almond Street, Derby, created much interest with her work and was the only undergraduate to present work at a lunchtime seminar at the recent Set For Britain Science Enterprise Event at the House of Commons.
Now in its ninth year, this highly successful and popular annual initiative sees Britain's researchers present posters at Westminster on ‘frontier’ science, engineering, medicine and technology research and compete for prestigious national medals, awards and prizes.
Dr Turner said: "Nazia has produced fantastic work and her project is rightly creating a lot of interest. The forgery of signatures is a problem in today’s society and as a result of technological advancement the introduction of digital signatures has become increasingly popular on UK documents such as driving licences and passports.
"The differences found between original and digital signatures has implications on such documents.
"The significance of the ink type used to create some documents which employ digital signatures has been shown and it is possible that by using a specific pen type, the number of differences found can be dramatically reduced."
Nazia has also met Derby North MP Bob Laxton and last week travelled to Brussels with friend Mohammed Sharif to meet officials at the European Union to present her findings and highlight the issue. She plans to undertake further work in this area to see if digital signatures can be forged.
Based within the University’s School of Science, Dr Turner and Nazia used thin layer chromatography and ultraviolet/visible spectroscopy in a series of laboratory experiments to identify variations.
Nazia said: "This study shows a statistically significant difference between original and digitally scanned signatures. Our methods showed that a different ink type used to create the original signature affects the number of differences found.
"Comparing ballpoint, fountain and rollerball pens, the forensic team found differences between the three inks which may contribute to the ability of the signature to be scanned for differing degrees of accuracy.
"These statistical differences show that digital signatures may not be a true representation of an original and that further investigation is needed."
The study also found a combination of rollerball pens and ballpoint pens to be most reliable and a combination of fountain pens and rollerball pens least reliable when signatures were digitally transferred.
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For more details please contact Simon Redfern, Senior Press and PR Officer, University of Derby on 01332 591942, or email s.redfern@derby.ac.uk.
