Method for secure data transmission between remote stations

• US 5,737,420 A
• Filed: 01/08/1996
• Issued: 04/07/1998
• Est. Priority Date: 09/07/1994
• Status: Expired due to Term

• Current Assignee: Bioscrypt, Inc. (Advent International Corporation)
• Original Assignee: Bioscrypt, Inc. (Advent International Corporation)
• Inventors: Stoianov, Alexei, Tomko, George J.
• Primary Examiner(s): Cain, David C.
• Application Number:
  US08/584,375
• Time in Patent Office: 820 Days
• Field of Search: 380/23, 380/21, 380/44, 380/49, 380/54, 380/3, 380/4
• US Class Current: 380/285
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/40145 Biometric identity checks
• CPC Class Codes: G06V 40/12 Fingerprints or palmprints
• CPC Class Codes: G06V 40/1347 Preprocessing; Feature extraction
• CPC Class Codes: G07C 9/25 using biometric data, e.g. fingerprints, iris scans or voice recognition
• CPC Class Codes: G07C 9/257 electronically G07C9/26 takes precedence
• CPC Class Codes: G07F 7/1008 Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: H04L 9/0866 involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics

Abstract

A method for permitting the secure handling or data between two remote stations firstly involves the generation of an encrypted decryption key which is based on a fingerprint information signal from a user of a first station, a fingerprint information signal from a user of a second station, and a key representing function derived from a random key. The encrypted decryption key is of the type with the property that when it is written to a spatial light modulator (SLM) of an optical correlator, the output of the correlator is similar when input with either one of the fingerprint information signals. The encrypted key is then stored at both stations. Thereafter a message encrypted with the key may be decrypted at either station by retrieving the encrypted key, writing the encrypted key to a filter of an optical correlator, inputting one of the fingerprint information signals to the correlator in order to allow recovery of the decryption key, and applying the decryption key to the encrypted message.

Claims

1. A method for permitting the secure passing of data between two remote stations, comprising the steps of:

obtaining from a user of a first of two remote stations, a first characteristic information signal;

obtaining from a user of a second of two remote stations, a second characteristic information signal;

generating a sequence of random characters to obtain a random key;

obtaining a key function which represents said key;

obtaining a Fourier transform of said key representing function;

obtaining at least one encrypted version of said key based on said Fourier transform of said key representing function, and a least one of said first characteristic information signal and said second characteristic information signal such that said key may be recovered by writing said at least one encrypted version of said encrypted key to a spatial light modulator (SLM) of an optic correlator and inputting either one of said first characteristic information signal and said second characteristic information signal to said optic correlator;

storing said at least one encrypted version of said key at each of said first station and said second station, whereby thereafter any message encrypted in such a way that it may be decrypted by said key may be decrypted at either of said two remote stations by retrieving said stored encrypted key, writing said at least one encrypted version of said encrypted key to a spatial light modulator (SLM) of an optic correlator and inputting either one of said first characteristic information signal and said second characteristic information signal to said optic correlator.

2. The method of claim 1 wherein the step of obtaining a first characteristic information signal comprises obtaining an optical beam modulated with a biometric image of a first body part of said user of said first station, registering said optical beam in a two-dimensional plane and digitizing said registered optical beam.

3. The method of claim 2 wherein the step of obtaining a second characteristic information signal comprises obtaining an optical beam modulated with a biometric image of a second body part of said user of said second station, registering said optical beam in a two-dimensional plane and digitizing said registered optical beam.

4. The method of claim 3 wherein the step of obtaining said key representing function comprises obtaining normalized orthogonal basis functions and, for each basis function, applying a character of said key as a co-efficient.

5. The method of claim 4 wherein said first characteristic information signal is obtained at said first station and including the steps of:

encrypting said digitized registered optical beam modulated with a biometric of a first body part with a pre-selected key to obtain an encrypted first biometric signal;

sending said encrypted first biometric signal to said second station;

utilizing said pre-selected key at said second station to decrypt said encrypted biometric of said first body part; and

obtaining said encrypted key at said second station.

6. The method of claim 4 wherein said key representing function is obtained at said first station and including the steps of:

encrypting said key representing function with a pre-selected key to obtain an encrypted key representing function;

sending said encrypted key representing function to said second station;

utilizing said pre-selected key at said second station to decrypt said encrypted key representing function; and

obtaining said encrypted key at said second station.

10. The method of claim 4 wherein said step of obtaining at least one encrypted version of said key is based on both said first characteristic information and said second characteristic information signal.

7. A method for the secure handling of data between two remote stations, comprising the steps of:

at a base station, encrypting a message such that said message may be decrypted by a decryption key;

passing said message to a remote station;

at said remote station,

obtaining from a user of said remote station a remote station user optical characteristic information signal;

retrieving from storage an encrypted version of said decryption key, said encrypted decryption key having the property that when it is written to a SLM of an optical correlator, the output of said correlator is similar when input with either one of said remote station user characteristic information signal or a base station user optical characteristic information signal;

writing a remote station optical correlator with said encrypted decryption key;

inputting said remote station correlator with a Fourier transform of said remote station user optical characteristic information signal;

regenerating said decryption key from an output of said remote station correlator; and

decrypting said message with said decryption key.

8. The method of claim 7 wherein the step of encrypting a message at said base station comprises encrypting said message utilizing said decryption key.

9. The method of claim 8 wherein the step of encrypting a message at said base station comprises the steps of:

obtaining from a base station user said base station optical characteristic information signal, such that said base station optical characteristic signal is impressed with characteristics of a body part of said base station user;

retrieving from storage said encrypted version of said decryption key;

writing a base station optical correlator with said encrypted decryption key;

inputting said base station correlator with said base station user optical characteristic information signal;

regenerating said decryption key from an output of said base station correlator; and

encrypting said message with said regenerated decryption key.