Constructing cancellable template with synthetic minutiae

Security measures have to be taken to protect the privacy of biometric data. Cancellable biometrics is proposed as an effective mechanism of using and protecting biometrics. The authors propose a new approach of constructing cancellable fingerprint template by mapping real minutiae to randomly generated minutiae in a synthetic template. The synthetic minutiae are selected based on the k -nearest neighbour method. One synthetic neighbour of each real minutia is utilised to construct the verification template (VT). Since the synthetic template is determined by a user-specific PIN and a random salt, the proposed method is in fact a two-factor authentication scheme. Multiple VTs can be generated easily by applying different PINs and salts to a real template. To prove the validity of the scheme, testing is carried out on three databases. A few factors affecting matching are also investigated. The results show that the constructed templates satisfy the requirements of cancellable biometrics. False non-match rate and False matching rate with the transformed templates can be much lower than those with the original templates by properly selecting the size of the synthetic templates and the ordinal number of the nearest neighbours. The proposed approach can also be utilised for multi-generation template transformation.