Method and apparatus for securely handling a personal identification

Abstract

A method and apparatus using biometric information (such as a fingerprint, an iris structure, etc.) as a cipher for encrypting and decrypting a personal identification number (PIN) which is used as an input to a PIN requiring device. The method of encryption of a PIN includes generating a sequence of random characters representing a PIN to be encrypted; obtaining a generating function such that the random characters are coefficients in an expansion of a square of said generating function over basis functions; and dividing a transform of the generating function by Fourier transformed information image signal to obtain the encrypted PIN. The latter is stored digitally or as a hologram in a personal card or a database. To decrypt the PIN, a full-complex spatial light modulator is illuminated with an optical beam carrying the Fourier transform of the biometric image of an individual to be identified. The encrypted PIN may be also stored in a reflective hologram which is nondestructively attached to a personal card, and the decryption of a PIN comprises illuminating the hologram with the beam carrying the Fourier transform of the biometric image. In other embodiments of the invention, a cipher may be derived from an intensity distribution (captured directly by a camera) of the Fourier spectrum of the biometric image. The PIN may be encrypted and decrypted either optically (with phase conjugation techniques) or digitally (using an encryption algorithm).