Brain activity provides novel biometric key
Kristina Kirby
15:17 16 January 2007
Source: NewScientist.com news service
By: Will Knight
An electronic security system that identifies people by monitoring the
unique pattern of electrical activity within their brain is being
tested by European scientists.
This novel biometric system should be difficult to forge, making it
suitable for high-security applications, claim the researchers behind
it. The system was developed by Dimitrios Tzovaras and colleagues at
the Centre for Research and Technology Hellas, in Greece. It uses an
established method for measuring activity in the brain, called
electroencephalography (EEG).
EEG measurements identify the location and intensity of
millisecond-long fluctuations in electrical activity in the brain via
electrodes positioned around a person's scalp. This can help
neuroscientists understand the function of different brain areas and
may also be used to diagnose and monitor neurological conditions such
as epilepsy and dementia.
Neural pathways
Since an individual's brain activity is determined by the unique
pattern of neural pathway in their brain, the same technique can be
used for identification, Tzovaras says. "It could be a very good
security control," he told New Scientist.
The authentication system requires a user to have EEG measurements
taken beforehand with further measurements for each authentication
test. This is done via a removable cap, which communicates wirelessly
with a computer that analyses the data gathered. The cap has fewer
electrodes than are normally used for EEG measurements, but can still
provide enough information for authentication, according to Tzovaras.
Currently users must sit quietly with their eyes shut during each test.
"We ask them to close their eyes and not speak"," Tzovaras says, which
provides "a much clearer picture".
The result of each authentication test is compared with the user's
pre-recorded measurements, using signal-processing algorithms. These
algorithms can be tuned to different security levels.
But users could eventually be required to perform specific tasks during
each test, he suggests, as this should also produce a unique EEG
"signature". The researchers envisage the set-up being used as part of
a building or computer security system and plan to test it as the
security control system for a laboratory in Germany in 2007.
Multiple biometrics
The biometric system is part of a wider European project called Human
Monitoring and Authentication using Biodynamic Indicators and
Behavioural Analysis (HUMABIO). The aim of this project is to combine
several different biometrics to create a more efficient and secure
overall system.
A separate group, led by Rafal Wardziński at Warsaw University of
Technology in Poland, is also working on EEG biometrics. In testing,
this group found that the method could identify subjects with 88%
accuracy.
However, John Daugman, a biometrics researcher at the University of
Cambridge, UK, questions the practicality of the approach. He says an
EEG cap could prove too cumbersome and invasive. "Wearing a wired
helmet with sensors on one's scalp might change the ambiance of the
workplace somewhat," he says.
Similarly, neuroimaging expert Olaf Hauk, also at the University of
Cambridge, believes using the system in a wide variety of situations,
particularly stressful ones, could complicate the results
significantly. "EEG varies greatly depending on a person's alertness,
or mental operations," Hauk told New Scientist. "You might not want to
be taken for someone else at the airport just because you had a bad
night before."