Security of registration data of fingerprint image with a server by use of the fractional Fourier transform

Recently, the personal identities by the fingerprint authentication have been increasing everywhere, for example, in the automatic logging into a PC, the access control and the diligence & indolence management in an office, and so on. In the fingerprint authentication, the fingerprint does not have to be remembered and there is no worry to be lost like a password, if once the information is registered with a server. The fingerprint, however, cannot be changed like a password if the information leaks out from the server. Therefore, the data processing is necessary not to be able to be decoded by another person. In this study, we use the fractional Fourier transform (FRT) as the method of data processing and analyze the fundamental properties of the decoded image in comparison with the original image.