Cracking Cancelable Fingerprint Template of Ratha

Cancelable biometrics may be a good approach to address the security and privacy concerns on biometric authentication. It uses some parameterized transforms to convert an original biometric template into a new version for authentication. The security of cancelable biometrics lies on noninvertibility of the transformed template, that is, the transforms should be noninvertible so that the original template can not be recovered. One way to achieve the noninvertibilty is through the use of many-to-one transforms. The idea of Ratha's scheme of generating fingerprint templates just depends on this. However, it is revealed in this paper that the form of the transforms and the parameters chosen in his implementation weaken the many-to-one property. This results in the possible recovery of original minutiae from one transformed template.