‘False matches’
The Home Office has responded to John Daugman’s warning that a deluge of false fingerprint matches would scupper the ID card scheme. The BBC tacked this report on to the end of an item about biometric visas:
Last month, Cambridge University IT expert Professor John Daugman warned that using fingerprints to identify individuals meant one in a thousand card-holders would be wrongly matched with other people’s details.
He said: “I don’t want to be very pessimistic and say this whole system is doomed to fail but I will say that just from analysing the mathematical requirements, if it is just fingerprint, it is unlikely to be able to succeed.”
…
But a Home Office spokesman said it was “not true” to suggest the database could not cope with vast records.
In the US, the FBI had a system with 47 million records and the US-Visit scheme – which records fingerprints of those arriving in the country – held details from more than 80 million people, he added.
The spokesman added: “The National Identity Scheme biometric checking processes are expected to utilise two biometrics (face and fingerprint), as well as manual inspection and biographic checks where necessary.
“We have not ruled out the use of iris technology for the NIS. However, we are sensibly starting with fingerprints, as these are in any case being introduced in passports and immigration documents.”
August 9th, 2007 at 07:38
Note how the Home Office spokesman is (deliberately?) rebutting the wrong point. No-one says that it’s hard to store 40-80 million sets of flat fingerprint images in one database. What the Prof. Daugman is saying is that trying to match a subject’s flat fingerprint against a database of 40 million sets of flat fingerprints could yield 40,000 false matches, making the fingperint database useless.
Storing someone’s own flat fingerprints on their own passport is different to collecting 40 million sets in a central database. It’s quite possible for the first to be useful and the second to be useless.
August 9th, 2007 at 14:43
Today marks another milestone in delivery of the National Identity Scheme with the start of the procurement process. (sic)
The notice for the National Identity Scheme Strategic Supplier Framework in the Official Journal of the European Union is available at: http://www.ukaea.org.uk/contract/ojeu.htm.
IPS press release
http://www.identitycards.gov.uk/press-2007-08-09.asp
August 10th, 2007 at 11:27
“False matches” is one problem. According to Professor Daugman, in the case of flat print fingerprints, the problem is of the order of one in a thousand.
That is bad enough.
But consider the problem of false non-matches. Again in the case of flat print fingerprionts, that problem is of the order of 200 in a thousand.
No-one sensible expects certainty from biometric systems. But this level of error surely suggests that the uncertainty is so great that any scheme based on these biometrics is a waste of money.