# US 7,797,606 B2 · Method for coding biometric data, method for controlling identity and devices for carrying out said methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,797,606 B2 - Document ID: US7797606B2 - Status: Granted - Kind: B2 - Application number: 11/570,992 - Filed: 2005-06-22 - Published: 2009-07-09 - Granted: 2010-09-14 - Earliest claimed: 2004-06-22 - Assignees: Morpho - Inventors: Hervé Chabanne - Web page: https://patentgrep.com/patent/US7797606B2 ## CPC - H04L 9/304: {based on error correction codes, e.g. McEliece} - G06F 21/32: using biometric data, e.g. fingerprints, iris scans or voiceprints - H04L 9/3231: {Biological data, e.g. fingerprint, voice or retina (network architectures or network communication protocols for supporting authentication of entities using biometrical features in a packet data network H04L63/0861)} - H04L 2209/16: Obfuscation or hiding, e.g. involving white box - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract The invention relates to a coding method consisting of the following steps: biometric data associated with an individual is obtained; a word, relating to an error correction code, selected in order to correct a quantity of errors in a relation to a statistical quantity of errors between two biometric measurements relating to the same individual, is generated, said word dissimulating information relating to said individual with the aid of a private function; and a combination is created between the biometric data thus obtained and the word thus generated. ## Claims ### Claim 1 A method of coding biometric data associated with respective individuals, comprising the following steps: obtaining biometric data associated with an individual; generating a word relating to an error correcting code chosen so as to correct a quantity of errors in conjunction with a statistical quantity of errors between two biometric measurements relating to one and the same individual, the word concealing, with the aid of a private function, an item relating to said individual; performing a combination between the biometric data obtained and the word generated. ### Claim 2 (depends on 1) The method as claimed in claim 1, in which said combination is an exclusive OR between the biometric data obtained and the word generated. ### Claim 3 (depends on 1) The method as claimed in claim 1, in which the item concealed in the word generated is an identity of said individual. ### Claim 4 (depends on 1) The method as claimed in one of the preceding claim 1, in which the generation of the word concealing, with the aid of a private function, an item relating to said individual is in accordance with the McEliece cryptosystem. ### Claim 5 (depends on 1) The method as claimed in claim 1, in which a substantially predetermined quantity of binary elements of the word generated or of the result of the combination between the biometric data obtained and the word generated is modified or erased. ### Claim 6 (depends on 5) The method as claimed in claim 5, in which the substantially predetermined quantity of binary elements of the word generated that is modified or that is erased is fixed as a function of a preset level of difficulty of retrieving the item concealed in said word, without knowing said private function, and of the statistical quantity of errors between two biometric measurements relating to one and the same individual. ### Claim 7 (depends on 5) The method as claimed in claim 5, in which the sum of said substantially predetermined quantity of binary elements of the word generated that is modified or that is erased and of said statistical quantity of errors between two biometric measurements relating to one and the same individual is less than or equal to the quantity of errors that the error correcting code chosen can correct. ### Claim 8 (depends on 1) The method as claimed in claim 1, in which the result of the combination between the biometric data obtained and the word generated is stored. ### Claim 9 A method of checking identity on the basis of previously stored biometric data, the biometric data being associated with respective individuals and each being coded with a respective word relating to an error correcting code, each word concealing, with the aid of a private function, an item relating to the individual associated with the corresponding biometric data, the error correcting code being chosen so as to correct a quantity of errors in conjunction with a statistical quantity of errors between two biometric measurements relating to one and the same individual, the method comprising the following steps: performing a biometric measurement relating to an individual; performing a combination between said biometric measurement and certain at least of the stored coded biometric data; and decoding the result of said combination on the basis of said private function, so as to retrieve the item concealed in the word with which the biometric data associated with said individual have been previously coded. ### Claim 10 (depends on 9) The method as claimed in claim 9, in which said combination is an exclusive OR between said biometric measurement and certain at least of the stored coded biometric data. ### Claim 11 (depends on 9) The method as claimed in claim 9, in which said item concealed in a word relating to the error correcting code, with which the biometric data associated with an individual are coded, is an identity of said individual. ### Claim 12 (depends on 11) The method as claimed in claim 11, furthermore comprising a step in which a check is carried out to verify that the identity retrieved after decoding of the result of the combination between the biometric measurement relating to said individual and certain at least of the stored coded biometric data corresponds to an identity provided by said individual. ### Claim 13 (depends on 9) The method as claimed in claim 9, in which the coding of the biometric data with a respective word relating to an error correcting code, each word concealing, with the aid of a private function, an item relating to the individual associated with the corresponding biometric data, complies with the McEliece cryptosystem. ### Claim 14 (depends on 9) The method as claimed in claim 9, in which each word with which respective biometric data are coded comprises a substantially predetermined quantity of modified or erased binary elements. ### Claim 15 (depends on 14) The method as claimed in claim 14, in which the substantially predetermined quantity of modified or erased binary elements for each word is fixed as a function of a preset level of difficulty of retrieving the item concealed in said word, without knowing said private function, and of said statistical quantity of errors between two biometric measurements relating to one and the same individual. ### Claim 16 (depends on 14) The method as claimed in claim 14, in which the sum of said substantially predetermined quantity of modified or erased binary elements for each word and of said statistical quantity of errors between two biometric measurements relating to one and the same individual is less than or equal to the quantity of errors that the error correcting code chosen can correct. ### Claim 17 A coding device for coding biometric data associated with respective individuals, the coding device comprising: means for obtaining biometric data associated with an individual; means for generating a word relating to an error correcting code chosen so as to correct a quantity of errors in conjunction with a statistical quantity of errors between two biometric measurements relating to one and the same individual, the word concealing, with the aid of a private function, an item relating to said individual; means for performing a combination between the biometric data obtained and the word generated. ### Claim 18 (depends on 17) The coding device as claimed in claim 17, in which the means for performing a combination between the biometric data obtained and the word generated are arranged for calculating an exclusive OR between the biometric data obtained and the word generated. ### Claim 19 (depends on 17) The coding device as claimed in claim 17, in which the item concealed in the word generated is an identity of said individual. ### Claim 20 (depends on 17) The coding device as claimed in claim 17, in which the means for generating a word concealing, with the aid of a private function, an item relating to said individual are in accordance with the McEliece cryptosystem. ### Claim 21 (depends on 17) The coding device as claimed in claim 17, comprising means for modifying or erasing a substantially predetermined quantity of binary elements of the word generated or of the result of the combination between the biometric data obtained and the word generated. ### Claim 22 (depends on 21) The coding device as claimed in claim 21, in which the substantially predetermined quantity of binary elements of the word generated that is modified or that is erased by said means for modifying or erasing is fixed as a function of a preset level of difficulty of retrieving the item concealed in said word, without knowing said private function, and of the statistical quantity of errors between two biometric measurements relating to one and the same individual. ### Claim 23 (depends on 21) The coding device as claimed in claim 21, in which the sum of said substantially predetermined quantity of binary elements of the word generated that is modified or that is erased by said means for modifying or erasing and of said statistical quantity of errors between two biometric measurements relating to one and the same individual is less than or equal to the quantity of errors that the error collecting code chosen can correct. ### Claim 24 (depends on 17) The coding device as claimed in claim 17, comprising means for storing the result of the combination between the biometric data obtained and the word generated. ### Claim 25 A checking device for checking identity on the basis of previously stored biometric data, the biometric data being associated with respective individuals and each being coded with a respective word relating to an error correcting code, each word concealing, with the aid of a private function, an item relating to the individual associated with the corresponding biometric data, the error correcting code being chosen so as to correct a quantity of errors in conjunction with a statistical quantity of errors between two biometric measurements relating to one and the same individual, the checking device comprising: means for performing a biometric measurement relating to an individual; means for performing a combination between said biometric measurement and certain at least of the stored coded biometric data; and means for decoding the result of said combination on the basis of said private function, so as to retrieve the item concealed in the word with which the biometric data associated with said individual have been previously coded. ### Claim 26 (depends on 25) The checking device as claimed in claim 25, in which the means for performing a combination between said biometric measurement and certain at least of the stored coded biometric data are arranged for calculating an exclusive OR between said biometric measurement and certain at least of the stored coded biometric data. ### Claim 27 (depends on 25) The checking device as claimed in claim 25, in which said item concealed in a word relating to the error correcting code, with which the biometric data associated with an individual are coded, is an identity of said individual. ### Claim 28 (depends on 27) The checking device as claimed in claim 27, furthermore comprising means for verifying that the identity retrieved after decoding of the result of the combination between the biometric measurement relating to said individual and certain at least of the stored coded biometric data corresponds to an identity provided by said individual. ### Claim 29 (depends on 25) The checking device as claimed in claim 25, in which the coding of the biometric data with a respective word relating to an error correcting code, each word concealing, with the aid of a private function, an item relating to the individual associated with the corresponding biometric data, complies with the McEliece cryptosystem. ### Claim 30 (depends on 25) The checking device as claimed in claim 25, in which each word with which respective biometric data are coded comprises a substantially predetermined quantity of modified or erased binary elements. ### Claim 31 (depends on 30) The checking device as claimed in claim 30, in which the substantially predetermined quantity of modified or erased binary elements for each word is fixed as a function of a preset level of difficulty of retrieving the item concealed in said word, without knowing said private function, and of said statistical quantity of errors between two biometric measurements relating to one and the same individual. ### Claim 32 (depends on 30) The checking device as claimed in claim 30, in which the sum of said substantially predetermined quantity of modified or erased binary elements for each word and of said statistical quantity of errors between two biometric measurements relating to one and the same individual is less than or equal to the quantity of errors that the error correcting code chosen can correct.