UW CSEP 590 Term paper Biometric Authentication Shankar Raghavan

Definition and Advantages Physical or behavioral characteristics  Much longer, random than a traditional password  Always there with the person  Unique to a person

Common biometric identifiers Biometric Identifier Distinctive ness Permanen ce Performan ce Acceptabil ity Fingerprint HighMediumHighMedium HandMedium IrisHigh Low RetinalHigh Low VoiceLow High SignatureLow High FRR/FAR are measures for accuracy

Authentication mechanism, threats  If template is compromised, is the biometric identifier lost for ever?  Is there any good method for Tye 1 or type 2 attacks?

Fingerprint minutiae

Attacks and Defences  Dummy finger (Type 1)  Gummy finger – Matsumoto (Type 1)  Hill climbing attack (Type 4)  Liveness detection (Type 1)  WSQ data hiding (Type 2)  Advantages of iris/retinal scannings  Image based challenge response systems

Fuzziness in biometrics  n of N attributes match  Application of Shamir’s secret sharing  Identity based encryption using bilinear maps Uses different polynomials for each user Generates a private key for every attribute user has, this is distinct and not shared with another user. Interpolates polynomial in an exponent

Fuzzy biometrics (backup)  Fuzzy commitment x and x’ will both decode to a similar value Not able to handle rotational/translational aspects of order invariances in an image very well.  Fuzzy vault Maps a set that hold the key to a secret onto a polynomial p ie each value in the set is an x coordinate for a point evaluated by p. Adds some noise or chaff so that the encrypted set becomes p(x),

Questions?