US5712912A — Method and apparatus for securely handling a pers…

Claim 1

Independent Claim 87 words

A method for securely storing at least a personal identification number (PIN), comprising the following steps: obtaining a biometric information signal bearing information from a body part; generating a sequence of random characters to obtain a PIN; obtaining a generating function such that said random characters of said PIN are parameters of said generating function; obtaining a transform of said generating function; encrypting said transform of said generating function with said biometric information signal to obtain an encrypted PIN; and writing said encrypted PIN into a store.

Claim 2

Independent Claim 87 words

A method for securely storing at least a personal identification number (PIN), comprising the following steps: obtaining a biometric information signal bearing information from a body part; generating a sequence of random characters to obtain a PIN; obtaining a generating function such that said random characters of said PIN are parameters of said generating function; obtaining a transform of said generating function; encrypting said transform of said generating function with said biometric information signal to obtain an encrypted PIN; and writing said encrypted PIN into a store.

Claim 3

Independent Claim 126 words

A method for recovering a personal identification number (PIN) for use in a device requiring a PIN for operation comprising the following steps: obtaining a biometric information signal bearing information from a body part; retrieving from storage an encrypted transform of a generating function, said generating function having characters of a PIN as parameters, said transform of said generating function previously encrypted with said biometric information signal; decrypting said previously encrypted transform of said generating function utilising said biometric information signal as a key for decryption to obtain a decrypted transformed generating function; undertaking an inverse transform operation on said decrypted transformed generating function to obtain an inverse transformed decrypted generating function; and obtaining parameters from said inverse transformed decrypted generating function to obtain a PIN.

Claim 4

Independent Claim 126 words

A method for recovering a personal identification number (PIN) for use in a device requiring a PIN for operation comprising the following steps: obtaining a biometric information signal bearing information from a body part; retrieving from storage an encrypted transform of a generating function, said generating function having characters of a PIN as parameters, said transform of said generating function previously encrypted with said biometric information signal; decrypting said previously encrypted transform of said generating function utilising said biometric information signal as a key for decryption to obtain a decrypted transformed generating function; undertaking an inverse transform operation on said decrypted transformed generating function to obtain an inverse transformed decrypted generating function; and obtaining parameters from said inverse transformed decrypted generating function to obtain a PIN.

Claim 5

Dependent Claim 30 words

The method of claim 1 including the steps of: encrypting information with a key which is a function of said PIN; and storing said encrypted information on said storage means.

Claim 6

Dependent Claim 30 words

The method of claim 2 including the steps of: retrieving encrypted information from said storage means; and decrypting said information with a key which is a function of said PIN.

Claim 7

Dependent Claim 106 words

The method of claim 1 wherein said step of obtaining a biometric information signal comprises obtaining a Fourier transform of a signal bearing information from a body part, said step of obtaining a transform of said generating function comprises obtaining a transform such that the transform has an inverse transform which exists and can be obtained optically and spatial frequencies which overlap with spatial frequencies of said Fourier transform of said signal bearing information from a body part and said step of encrypting said transform comprises dividing said transform of said generating function by said Fourier transform of said signal bearing information from a body part.

Claim 8

Dependent Claim 42 words

The method of claim 2 wherein said step of obtaining a biometric information signal comprises: obtaining a coherent optical beam modulated with a biometric image of a body part; and obtaining a beam carrying an optical Fourier transform of said biometric image.

Claim 9

Dependent Claim 113 words

The method of claim 6 wherein said step of decrypting said previously encrypted transform further comprises the steps of: addressing a full-complex spatial light modulator (SLM) with said encrypted transform; and illuminating said SLM with said beam carrying the Fourier transform of the biometric image to obtain an output beam; wherein the step of undertaking an inverse transform operation on said decrypted transformed generating function comprises obtaining an optical transform of said output beam; and wherein the step of obtaining parameters from said inverse transformed decrypted generating function to obtain a PIN comprises the steps of: registering an intensity distribution of said transformed output beam; and retrieving said PIN from said intensity distribution.

Claim 10

Dependent Claim 44 words

The method of claim 5 wherein said step of writing the encrypted PIN into storage means further comprises: recording a hologram, a complex amplitude of a spatial grating of said hologram being proportional to said encrypted PIN; and attaching said hologram to storage means.

Claim 11

Dependent Claim 95 words

The method of claim 8 wherein said step of recording a hologram further comprises the steps of: determining a complex conjugate of said encrypted PIN; determining an inverse Fourier transform of said complex conjugate to obtain an inverse transformed addressing signal; addressing a full-complex SLM with said inverse transformed addressing signal; illuminating said SLM with coherent light to produce an object beam; obtaining an optical Fourier transform of said object beam; and recording a reflective hologram by means of interference of said object beam with a reference beam which is coherent with said object beam.

Claim 12

Dependent Claim 122 words

The method of claim 6 wherein said step of decrypting said transform of said generating function further comprises the step of illuminating a prerecorded hologram with said beam carrying the Fourier transform of the biometric image; wherein the step of undertaking an inverse transform operation on said decrypted transformed generating function comprises obtaining an optical transform of a beam diffracted from said hologram; and wherein the step of obtaining parameters from said inverse transformed decrypted generating function to obtain a PIN comprises: registering an intensity distribution of said transformed diffracted beam; and calculating scalar products of said intensity distribution and each of a plurality of basis functions to obtain a PIN, said basis functions being the same as they were during encryption.

Claim 13

Dependent Claim 42 words

The method of claim 1 wherein said step of obtaining a biometric information signal comprises: obtaining a coherent optical beam modulated with a biometric image of a body part; and registering an intensity distribution of a Fourier spectrum of said biometric image.

Claim 14

Dependent Claim 178 words

The method of claim 11 including the steps of: (a) processing said intensity distribution of the Fourier spectrum of the biometric image; and (b) deriving a cipher function from said processed intensity distribution; wherein the step of obtaining a generating function comprises obtaining a generating function such that said random characters are coefficients in an expansion of square of said generating function over basis functions; wherein said step of obtaining a transform of said generating function comprises obtaining a first transform of said generating function such that the first transform has an inverse transform which exists and can be obtained optically and spatial frequencies which overlap with spatial frequencies of said Fourier spectrum of said biometric image; and wherein the step of encrypting said transform of said generating function comprises the steps of: (i) obtaining a product of said first transform of the generating function and a complex exponent of said cipher function; and (ii) obtaining a second transform of said product such that said second transform has an inverse transform which exists and can be performed optically.

Claim 15

Dependent Claim 44 words

The method of claim 12 wherein step (a) comprises: mapping said intensity distribution of the Fourier spectrum of the biometric image with a saturation function; further processing said intensity distribution with a randomizing operator; and obtaining a Gabor transform of said processed intensity distribution.

Claim 16

Dependent Claim 22 words

The method of claim 12 wherein step (b) comprises binarization or quantization of said processed intensity distribution to derive a cipher function.

Claim 17

Dependent Claim 41 words

The method of claim 4 wherein said step of obtaining a biometric information signal comprises: obtaining a coherent optical beam modulated with a biometric image of a body part; and registering an intensity distribution of Fourier spectrum of said biometric image.

Claim 18

Dependent Claim 227 words

The method of claim 15 including the steps of: (a) processing said intensity distribution of the Fourier spectrum of the biometric image; (b) deriving a cipher function from said processed intensity distribution; wherein the step of decrypting said previously encrypted transform of said generating function comprises the steps of: (c) addressing a first full-complex SLM with said encrypted transform; (d) addressing a second phase-only SLM with the sign-inversed cipher function; (e) illuminating said first SLM with a coherent light beam to obtain a beam modulated with said encrypted transform; (f) obtaining an optical transform of said modulation beam such that said transform is inverse to a second transform which was performed during encryption; (g) illuminating said second SLM with said optically transformed beam to obtain an output beam; wherein the step of undertaking an inverse transform operation comprises; (h) obtaining an optical transform of said output beam such that said transform is inverse to a first transform which was performed during encryption; and wherein the step of obtaining parameters from said inverse transformed decrypted generating function to obtain a PIN comprises the steps of: (i) registering an intensity distribution of said transformed output beam; and (j) calculating scalar products of said intensity distribution and each of a plurality of basis functions to obtain a PIN, said basis functions being the same as basis functions used during encryption.

Claim 19

Dependent Claim 44 words

The method of claim 16 wherein step (a) comprises: mapping said intensity distribution of the Fourier spectrum of the biometric image with a saturation function; further processing said intensity distribution with a randomizing operator; and obtaining a Gabor transform of said processed intensity distribution.

Claim 20

Dependent Claim 22 words

The method of claim 16 wherein step (b) comprises binarization or quantization of said processed intensity distribution to derive a cipher function.

Claim 21

Dependent Claim 44 words

The method of claim 12 wherein said step of writing the encrypted PIN into storage means further comprises: recording a hologram, a complex amplitude of a spatial grating of said hologram being proportional to said encrypted PIN; and attaching said hologram to storage means.

Claim 22

Dependent Claim 106 words

The method of claim 19 wherein said recording a hologram comprises the steps of: addressing a first amplitude-only SLM with said generating function; addressing a second phase-only SLM with said cipher function; illuminating said first SLM with a coherent light beam to obtain a beam modulated with said generating function; obtaining a first optical transform of said modulated beam; illuminating said second SLM with said optically transformed beam to obtain an object beam; obtaining a second optical transform of said beam; and recording a reflective hologram by means of interference of said transformed object beam with a reference beam which is coherent with said object beam.

Claim 23

Dependent Claim 179 words

The method of claim 15 wherein said step of decrypting said transform of said generating function further comprises the steps of: addressing a phase-only SLM with the sign-inversed cipher function; illuminating a pre-recorded hologram with a coherent light beam; obtaining an optical transform of a beam diffracted from said hologram such that said transform is inverse to a second complex-conjugated transform which was performed during encryption; illuminating said SLM with said transformed diffracted beam to obtain an output beam; wherein the step of undertaking an inverse transform operation on said decrypted transformed generating function comprising obtaining an optical transform of said output beam such that said transform is inverse to the first complex conjugated transform which was performed during encryption; and wherein the step of obtaining parameters from said inverse transformed decrypted generating function to obtain a PIN comprises: registering an intensity distribution of said transformed output beam; and calculating scalar products of said intensity distribution and each of a plurality of basis functions to obtain a PIN, said basis functions being the same as they were during encryption.

Claim 24

Dependent Claim 91 words

The method of claim 11 including the steps of: encrypting information with a key which is a function of said PIN; and storing said encrypted information on said storage means; and wherein said encrypting a transform of said generating function step further comprises the steps of: (a) processing said intensity distribution of the Fourier spectrum of the biometric image; (b) deriving a unique vector from said processed intensity distribution; and (c) encrypting said transform of said generating function with a symmetric algorithm, said unique vector being a key to said algorithm.

Claim 25

Dependent Claim 25 words

The method of claim 22 wherein step (a) comprises mapping said intensity distribution of the Fourier spectrum of the biometric image with a saturation function.

Claim 26

Dependent Claim 18 words

The method of claim 23 wherein step (a) further comprises obtaining Gabor transform of said processed intensity distribution.

Claim 27

Dependent Claim 112 words

The method of claim 22 wherein step (b) comprises the steps of: selecting a pre-determined number of highest peaks in said processed intensity distribution to generate a selected peaks array; transforming said selected peaks array to a polar co-ordinate system, the centre of which corresponds to the zeroth spatial frequency of said Fourier spectrum, to generate a polar co-ordinates array, each element in said polar co-ordinates array being represented by a vector comprising polar co-ordinates and a peak amplitude; and deriving said unique vector from said polar co-ordinates array such that the number of elements in said unique vector are equal to a dimension of a key required by said symmetric algorithm.

Claim 28

Dependent Claim 111 words

The method of claim 22 wherein step (b) comprises the steps of: transforming said processed intensity distribution to a polar co-ordinates system, the centre of which corresponds to the zeroth spatial frequency of said Fourier spectrum, to generate a polar co-ordinates distribution; calculating a pre-determined number of first coefficients in an expansion of said polar co-ordinates distribution over spherical harmonics; calculating a square of absolute value of each said coefficient, and normalizing said squares to obtain a normalized array; and deriving said unique vector from said normalized array such that the number of elements in said unique vector are equal to a dimension of a key required by said symmetric algorithm.

Claim 29

Dependent Claim 81 words

Apparatus for encrypting a PIN, comprising: means for obtaining a biometric information signal bearing characteristics of a body part; means for generating a sequence of random characters to obtain a PIN; means for obtaining a generating function comprising said random characters as parameters; means for obtaining a transform of said generating function; means for encrypting said transform of said generating function with said biometric information signal to obtain an encrypted PIN; and means for writing said encrypted PIN into a store.

Claim 30

Dependent Claim 81 words

Apparatus for encrypting a PIN, comprising: means for obtaining a biometric information signal bearing characteristics of a body part; means for generating a sequence of random characters to obtain a PIN; means for obtaining a generating function comprising said random characters as parameters; means for obtaining a transform of said generating function; means for encrypting said transform of said generating function with said biometric information signal to obtain an encrypted PIN; and means for writing said encrypted PIN into a store.

Claim 31

Dependent Claim 110 words

Apparatus for decrypting a PIN, comprising: means for obtaining a biometric information signal bearing characteristics of a body part; means for reviewing from storage a transform of a generating function, said generating function having characters of a PIN as parameters, said transform of said generating function previously encrypted with said biometric information signal; means for decrypting said previously encrypted transform of said generating function, said biometric information signal being a key to said encrypted transform; means for undertaking an inverse transform operation on said decrypted transform to obtain an inverse transformed decrypted generating function; and means for obtaining parameters from said inverse transformed decrypted generating function to obtain a PIN.

Claim 32

Dependent Claim 110 words

Apparatus for decrypting a PIN, comprising: means for obtaining a biometric information signal bearing characteristics of a body part; means for reviewing from storage a transform of a generating function, said generating function having characters of a PIN as parameters, said transform of said generating function previously encrypted with said biometric information signal; means for decrypting said previously encrypted transform of said generating function, said biometric information signal being a key to said encrypted transform; means for undertaking an inverse transform operation on said decrypted transform to obtain an inverse transformed decrypted generating function; and means for obtaining parameters from said inverse transformed decrypted generating function to obtain a PIN.

Claim 33

Dependent Claim 29 words

The method of claim 5 wherein the step of obtaining a generating function comprises obtaining a plurality of orthogonal basis functions, said characters being parameters of said basis functions.

Claim 34

Dependent Claim 37 words

The method of claim 5 wherein the step of obtaining a generating function comprises obtaining a generating function such that said random characters are coefficients in an expansion of square of said generating function over basis functions.

Claim 35

Dependent Claim 52 words

The method of claim 7 wherein the step of retrieving said PIN from said intensity distribution comprises calculating scalar products of said intensity distribution and each of a plurality of basis function to obtain a PIN, said basis functions being the same as basis functions used during encryption of said encrypted PIN.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-01-26	2001-07-28	2002-01-27	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-01-26	2005-07-28	2006-01-27	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-01-26	2009-07-28	2010-01-27	$7700.00	Window Closed / Lapsed

Method and apparatus for securely handling a personal identification number or cryptographic key using biometric techniques

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