IMAGES ENCRYPTIONVIA DISCRETE FRACTIONALFOURIERTRANSFORM AND JIGSAWTRANSFORM. CASE STUDY:FINGERPRINTS
Juan M. Vilardy, Lorenzo Mattos · 2009
A new images encryption method using The Discrete Frac tional Fourier Transform (DFrFT) andthe Jigsaw transform is proposed. The mainfeature ofthis encryption scheme is that the encryptedimage is real andhas the same size as the original one, being this encryptedimage much more conven ient for either its storage or its transmission on digital com munication networks. Using the Jigsaw transform the secu rity of the encrypted image is increased and the random phase masks used in many images cryptosystems based on Fractional Fourier Transform (FrFT) are eliminated Fi nally, for the new proposedencryption method, afingerprint encryption digital algorithm was developed There are twelve keys used in the cryptographic algorithm imple mented, which are constituted by the six DFrFTsfractional orders and the six random permutations used in Jigsaw transform; all these keys arenecessaryfor a correct decryp tion, obtaining a high level security in protecting finger printsfor a particular application.