  Fingerprint is widely used in a variety of applications. Security measures
have to be taken to protect the privacy of fingerprint data. Cancelable
biometrics is proposed as an effective mechanism of using and protecting
biometrics. In this paper we propose a new method of constructing cancelable
fingerprint template by combining real template with synthetic template.
Specifically, each user is given one synthetic minutia template generated with
random number generator. Every minutia point from the real template is
individually thrown into the synthetic template, from which its k-nearest
neighbors are found. The verification template is constructed by combining an
arbitrary set of the k-nearest neighbors. To prove the validity of the scheme,
testing is carried out on three databases. The results show that the
constructed templates satisfy the requirements of cancelable biometrics.
