Method of Dynamically Encrypting Fingerprint Data and Related Fingerprint Sensor

Abstract

A dynamic encryption type fingerprint sensor includes a capacitive array sensing fingerprints and producing fingerprint data, an embedded non-volatile memory (eNVM) storing a one-time code (OTC) and an encryption algorithm indicator, and a logic algorithm circuit encrypting the fingerprint data produced by the capacitive array according to the OTC and the encryption algorithm indicator. The logic algorithm circuit includes an encryption circuit having a plurality of logic encryption circuits selected using the encryption algorithm indicator, the encryption circuit encrypting the fingerprint data using selected logic encryption circuits of the plurality of logic encryption circuits according to the OTC. A control circuit is used for controlling operation of the capacitive array, the eNVM, and the logic algorithm circuit.

What is claimed is: 
     
         1 . A dynamic encryption type fingerprint sensor, comprising:
 a capacitive array sensing fingerprints and producing fingerprint data;   an embedded non-volatile memory (eNVM) storing a one-time code (OTC) and an encryption algorithm indicator;   a logic algorithm circuit encrypting the fingerprint data produced by the capacitive array according to the OTC and the encryption algorithm indicator, the logic algorithm circuit comprising:
 an encryption circuit comprising a plurality of logic encryption circuits selected using the encryption algorithm indicator, the encryption circuit encrypting the fingerprint data using selected logic encryption circuits of the plurality of logic encryption circuits according to the OTC; and 
   a control circuit for controlling operation of the capacitive array, the eNVM, and the logic algorithm circuit.   
     
     
         2 . The dynamic encryption type fingerprint sensor of  claim 1 , wherein one or more of the plurality of logic encryption circuits is selected using the encryption algorithm indicator, and the one or more selected logic encryption circuits encrypt the fingerprint data according to the OTC. 
     
     
         3 . The dynamic encryption type fingerprint sensor of  claim 1 , wherein the encryption algorithm indicator is updated periodically, and an updated encryption algorithm indicator is stored in the eNVM. 
     
     
         4 . The dynamic encryption type fingerprint sensor of  claim 1 , wherein the encryption algorithm indicator is updated after every time the logic algorithm circuit is used for encrypting fingerprint data, and an updated encryption algorithm indicator is stored in the eNVM. 
     
     
         5 . The dynamic encryption type fingerprint sensor of  claim 1 , wherein the OTC is encrypted. 
     
     
         6 . The dynamic encryption type fingerprint sensor of  claim 1 , wherein the OTC is received from outside the dynamic encryption type fingerprint sensor. 
     
     
         7 . The dynamic encryption type fingerprint sensor of  claim 1 , wherein the logic algorithm circuit further comprises a new OTC generation circuit for generating a new OTC after the OTC has been used for encrypting fingerprint data. 
     
     
         8 . The dynamic encryption type fingerprint sensor of  claim 7 , wherein new OTC is generated randomly or generated based on a previous value of the OTC. 
     
     
         9 . The dynamic encryption type fingerprint sensor of  claim 1 , wherein the dynamic encryption type fingerprint sensor is formed on a single chip. 
     
     
         10 . The dynamic encryption type fingerprint sensor of  claim 1 , wherein the eNVM further stores a product identification of the dynamic encryption type fingerprint sensor to identify the dynamic encryption type fingerprint sensor. 
     
     
         11 . A method of dynamically encrypting fingerprint data with a fingerprint sensor, the method comprising:
 sensing fingerprints with a capacitive array of the fingerprint sensor and producing corresponding fingerprint data;   receiving an encryption algorithm indicator and a one-time code (OTC);   selecting one or more logic encryption circuits of a plurality of logic encryption circuits using the encryption algorithm indicator; and   encrypting the fingerprint data produced by the capacitive array with the one or more selected logic encryption circuits according to the OTC.   
     
     
         12 . The method of  claim 11 , wherein the OTC and the encryption algorithm indicator are stored in an embedded non-volatile memory (eNVM) of the fingerprint sensor. 
     
     
         13 . The method of  claim 12 , wherein the encryption algorithm indicator is updated periodically, and an updated encryption algorithm indicator is stored in the eNVM. 
     
     
         14 . The method of  claim 12 , wherein the encryption algorithm indicator is updated after every time the logic algorithm circuit is used for encrypting fingerprint data, and an updated encryption algorithm indicator is stored in the eNVM. 
     
     
         15 . The method of  claim 12 , wherein the eNVM further stores a product identification of the fingerprint sensor to identify the fingerprint sensor. 
     
     
         16 . The method of  claim 11 , wherein the OTC is encrypted. 
     
     
         17 . The method of  claim 11 , wherein the OTC is received from outside the fingerprint sensor. 
     
     
         18 . The method of  claim 11 , further comprising generating a new OTC after the OTC has been used for encrypting fingerprint data. 
     
     
         19 . The method of  claim 18 , wherein new OTC is generated randomly or generated based on a previous value of the OTC. 
     
     
         20 . The method of  claim 11 , wherein the fingerprint sensor is formed on a single chip.