Monday, November 19, 2007

Reconstructing fingerprint images from templates

This is for everyone who thinks fingerprints cannot be reverse engineered from biometric systems, and especially for Jim Knight MP, the Labour Minister for Schools and Learners, who offered up the below incorrect information in a parliamentary debate in July this year with Greg Mulholland MP:

"Secondly, as I stated earlier, it is not possible to recreate a fingerprint using the numbers that are stored. The algorithm generates a unique number, producing no information of any use to identity thieves. I shall quote from a statement from the Information Commissioner’s Office—a thoroughly independent source—that says in the third paragraph:

“Full fingerprint images are not stored and cannot be generated (‘reverse engineered’) from the template.”

I hope that that is clear to all those listening, because it is an important reassurance on the points that the hon. Gentleman has made." ...absolutely crystal Jim.

1. Original fingerprint scan
2. Stored fingerprint template

3. Print reconstructed from template
Arun Ross, Member, IEEE, Jidnya Shah, and Anil K. Jain, Fellow, IEEE
April 2007
(as shown on the Leave Them Kids Alone site)


Anonymous said...

At the public meeting held at Morley High School, parents were reassured that only a sequence of numbers would be stored and that it could not be reversed! This was clearly stated by the biometric salesman.

Also, on the BBC Radio 4 "You & Yours" interview with regards to the biometric system at Morley High School, MP Jim Knight stated the following:
"children are not fingerprinted, there is no ink pad, all that happens is that a long number is generated from part of the finger. That can't be reversed back into a fingerprint"

Anonymous said...

Fingerprint minutiae are an intermediate "half-way" house to a template. A template is non-reversible back to minutiae. Schools deciding whether to implement fingerprint systems should ask whether minutiae data are being stored in the system, or templates only. The drawback of storing templates only is that it may lock you in to a particular vendor's fingerprint technology (fingerprint images and minutiae are inter-operable). There are other systems, such as iris recognition in which a digital photograph of the eye is taken, which do not have the forensic connotations of fingerprint. These are coming down in price and are now competitive with fingerprint.