Office Action 2: Final Rejection (2024-05-31)
Rejection types: 102 - Lack of Novelty

CLAIMS:
Listing of Claims:

This listing of claims will replace all prior versions, and listings, of claims in the application.

1\. (Currently Amended) A PUF circuit comprising one or more sensors, the PUF circuit comprising a processor configured to receive information about a subset of sensor components of a sensor, the PUF circuit being configured to apply one or more challenges to the subset of sensor components under uniform conditions, the PUF circuit comprising a receiver configured to receive output signal values from the subset of sensor components, in response to a challenge applied to said subset of sensor components, wherein the PUF circuit comprises a data communication channel, and the PUF circuit is configured to:
determine one or more statistical properties of \[\[the\]\] a noise distribution of said output signal values;
receive input data IN from one or more external data sources using the data communication channel;
determine a response R to said one or more challenges from said statistical properties and said selected input data IN received from said one or more external data sources, said response being a digital signature, wherein the input Data IN are used to handle of the PUF circuit.

2\. (Currently Amended) The circuit of Claim 1, wherein the circuit is configured to communicate data OUT to one or more external entities using said data communication channel.

3\. (Currently Amended) The circuit of Claim 1, wherein the received data IN calibrates said one or more sensors.

4\. (Currently Amended) The circuit of Claim 1, wherein the received data IN comprises information leading directly or indirectly to disabling of the PUF circuit.

5\. (Currently Amended) The circuit of Claim 1, wherein the received data IN, or parts thereof, serves as or contributes to a challenge of the PUF circuit, said circuit providing a response in response to said one or more challenges.

6\. (Currently Amended) The circuit of Claim 1, wherein the received data IN, or parts thereof, signs a challenge of the PUF circuit.

7\. (Currently Amended) The circuit of Claim \[\[1\]\] 2, wherein said at least one external entities comprise at least one computer or another PUF circuit.

8\. (Currently Amended) The circuit of Claim 1, wherein an applied challenge C modifies and/or controls and/or influences communicated data OUT.

9\. (Currently Amended) The circuit of Claim 1, wherein communicated data OUT modifies an applied challenge C.

10\. (Previously Presented) The circuit of Claim 1, wherein data IN modifies the response R, while or after the response R is produced.

11\. (Currently Amended) The circuit of Claim 1, wherein \[\[a\]\] the response R retroacts on data IN.

12\. (Previously Presented) The circuit of Claim 1, wherein the response R modifies the challenge C.

13\. (Currently Amended) A system comprising two or more \[\[of\]\] PUF circuits according to Claim 1, the PUFs circuits comprising a first PUF circuit and a second PUF circuit, wherein communicated data OUT of a first circuit is taken as an input data IN by a second circuit.

14\. (Currently Amended) \[\[The\]\] A system comprising two or more efPUF circuits according to Claim 1, the PUFs circuits comprising a first PUF circuit and a second PUF circuit, wherein the response R of a first circuit is taken as an input data IN by a second circuit.

15\. (Currently Amended) \[\[The\]\] A system comprising two or more efPUF circuits according to Claim 1, the PUFs circuits comprising a first PUF circuit and a second PUF circuit, wherein communicated data OUT of a first circuit is taken as a challenge C by a second circuit.

16\. (Currently Amended) \[\[The\]\] A system comprising two or more efPUF circuits according to Claim 1, the PUFs circuits comprising a first PUF circuit and a second PUF circuit, wherein the response R of a first circuit is taken as a challenge C by a second circuit.

17\. (Currently Amended) A method for generating a digital signature, the method being implemented by a PUF circuit comprising one or more sensors, the method comprising receiving information about a subset of sensor components of a sensor, applying one or more challenges to the subset of sensor components under uniform conditions, and receiving output signal values from the subset of sensor components, in response to a challenge applied to said subset of sensor components,wherein method comprises:determining one or more statistical properties of the noise distribution of said output signal valueSVG {EMBED HERE} 0.0770.133 receiving input data IN from one or more external data sources using the data communication channel;
determining a response to the challenge from said statistical properties and selected input data IN received from said one or more external data sources, said response being a digital signature,
wherein the input Data IN are used to handle of the PUF circuit

Office Action Dated: September 13, 2023

.

18\. Cancelled.

OFFICE ACTION:
DETAILED ACTION
Notice of Pre-AIA  or AIA  Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Acknowledgment is made of priority based on European Patent Application EP18305929.4 filed on July 11, 2018.
Information Disclosure Statement
Acknowledgment is made of the information disclosure statements filed on February 6, 2024. The U.S. patents and Foreign Patents have been considered.
Response to Amendment
The following is a final office action in response to communications received on December 7, 2023.
Claims 1-9, 11, and 13-17 have been amended.
Claim 18 has been canceled.
Applicant’s amendment and response to the claims are sufficient to overcome the 35 USC 112 (b) and the 35 U.S.C. 101 rejection set forth in the previous office action. The examiner has withdrawn the rejections.
Response to Arguments
Applicant's arguments filed on December 7, 2023, have been fully considered, but they are not all persuasive.
As per the prior art rejection of claim 1 in page 6-9, applicant argues that Cambou does not teach or suggest at least these features of amended independent claim 1.
The examiner respectfully disagrees. Cambou discloses a PUF circuit comprising one or more sensors, the PUF circuit comprising a processor configured to receive information about a subset of sensor components of a sensor, the PUF circuit being configured to apply one or more challenges to the subset of sensor components under uniform conditions; the PUF circuit comprising a receiver configured to receive output signal values from the subset of sensor components, in response to a challenge applied to said subset of sensor components, wherein the PUF circuit comprises a data communication channel (The art teaches in Parag. [0033] and FIG. 4 a sensor system 400 that can be authenticated using calibration table based PUF challenge-response pairs (CRPs) alone or in combination with SRAM based PUF CRPs. The sensor system 400 includes a sensor 402, an ADC 404, a digital processor 406, a calibration able 408 (The calibration tables each store calibration data for corresponding sensors, see Parag. [0032]), a SRAM cache 410, and a PUF generator 416. The PUF generator 416 is connected to both the digital processor 406 and the calibration table 408. The art teaches in Parag. [0034] that “secure terminal” refers to a device (e.g., computer hardware) connected to a computer network that uses PUF verification (e.g., PUF verification performed using sensor system 400. The art teaches in Parag. [0038] that sensor system 400 is configured as a single-PUF system that uses only data from the calibration table 408 as a basis for PUF CRP generation, the PUF generator 416 initially generates one or more PUF challenges using the bit stream of calibration data stored in the calibration table 408. The sensor system 400 is connected to a secure terminal 418 which is connected to a secure memory 420), and the PUF circuit is configured to:
determine one or more statistical properties of a noise distribution of said output signal values (The art teaches Parag. [0026] that sensor systems such as the sensor system 100 need to be calibrated with known detectable (e.g., physical or chemical) signals that produce known (i.e., expected) electrical signals when processed by a sensor such as the sensor 102. Possible calibrations may include determining a reset position (i.e. obtaining a zero as an output signal when no detectable signal parameter is sensed) to correct deviations for accurate reading, and to enhance the linearity of the electric signal. Other corrections that may be part of the calibration process include adjusting temperature coefficients, biasing conditions, and cancelling background noise);
receive input data IN from one or more external data sources using the data
communication channel (The art teaches in Parag. [0029] at 230, a processor generates calibration data by comparing the sensor data to the expected results associated with the known detectable signals. The art teaches in Parag. [0030] at 240, the calibration data is stored in a calibration table in non-volatile memory of the sensor system. The processor may be a digital processor that is external to the sensor system (the input data is received from an external data source through a communication channel));
determine a response R to said one or more challenges from said statistical properties and said selected input data IN received from said one or more external data sources, said response being a digital signature, wherein the input Data IN are used to handle of the PUF circuit (The art teaches in Parag. [0039] that PUF challenge data includes both the instructions for PUF response generation and the PUF challenges that were initially generated while setting up the initial cryptographic protocol for the sensor system 400. The instructions are sent to the PUF generator 416, which then extracts one or more PUF responses (digital signatures) from the calibration table 408 based on the instructions. The art teaches in Parag. [0033] that sensor system 400 that can be authenticated using calibration table based PUF challenge-response pairs (CRPs) alone or in combination with SRAM based PUF CRPs).
Claim Objections
Claim 17 is objected to because of the following informality:
In claim 17, line 8, “the noise distribution” should read “a noise distribution.”
Appropriate correction is required.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-17 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Cambou (Pub. No. US 2018/0006830).
Claim 1.	Cambou discloses a PUF circuit comprising one or more sensors, the PUF circuit comprising a processor configured to receive information about a subset of sensor components of a sensor, the PUF circuit being configured to apply one or more challenges to the subset of sensor components under uniform conditions; the PUF circuit comprising a receiver configured to receive output signal values from the subset of sensor components, in response to a challenge applied to said subset of sensor components, wherein the PUF circuit comprises a data communication channel (The art teaches in Parag. [0033] and FIG. 4 a sensor system 400 that can be authenticated using calibration table based PUF challenge-response pairs (CRPs) alone or in combination with SRAM based PUF CRPs. The sensor system 400 includes a sensor 402, an ADC 404, a digital processor 406, a calibration able 408 (The calibration tables each store calibration data for corresponding sensors, see Parag. [0032]), a SRAM cache 410, and a PUF generator 416. The PUF generator 416 is connected to both the digital processor 406 and the calibration table 408. The art teaches in Parag. [0034] that “secure terminal” refers to a device (e.g., computer hardware) connected to a computer network that uses PUF verification (e.g., PUF verification performed using sensor system 400. The art teaches in Parag. [0038] that sensor system 400 is configured as a single-PUF system that uses only data from the calibration table 408 as a basis for PUF CRP generation, the PUF generator 416 initially generates one or more PUF challenges using the bit stream of calibration data stored in the calibration table 408. The sensor system 400 is connected to a secure terminal 418 which is connected to a secure memory 420), and the PUF circuit is configured to:
determine one or more statistical properties of a noise distribution of said output signal values (The art teaches Parag. [0026] that sensor systems such as the sensor system 100 need to be calibrated with known detectable (e.g., physical or chemical) signals that produce known (i.e., expected) electrical signals when processed by a sensor such as the sensor 102. Possible calibrations may include determining a reset position (i.e. obtaining a zero as an output signal when no detectable signal parameter is sensed) to correct deviations for accurate reading, and to enhance the linearity of the electric signal. Other corrections that may be part of the calibration process include adjusting temperature coefficients, biasing conditions, and cancelling background noise);
receive input data IN from one or more external data sources using the data
communication channel (The art teaches in Parag. [0029] at 230, a processor generates calibration data by comparing the sensor data to the expected results associated with the known detectable signals. The art teaches in Parag. [0030] at 240, the calibration data is stored in a calibration table in non-volatile memory of the sensor system. The processor may be a digital processor that is external to the sensor system (the input data is received from an external data source through a communication channel));
determine a response R to said one or more challenges from said statistical properties and said selected input data IN received from said one or more external data sources, said response being a digital signature, wherein the input Data IN are used to handle of the PUF circuit (The art teaches in Parag. [0039] that PUF challenge data includes both the instructions for PUF response generation and the PUF challenges that were initially generated while setting up the initial cryptographic protocol for the sensor system 400. The instructions are sent to the PUF generator 416, which then extracts one or more PUF responses (digital signatures) from the calibration table 408 based on the instructions. The art teaches in Parag. [0033] that sensor system 400 that can be authenticated using calibration table based PUF challenge-response pairs (CRPs) alone or in combination with SRAM based PUF CRPs).
Claim 2.	Cambou discloses the circuit of Claim 1,
Cambou further discloses wherein the circuit is configured to communicate data OUT
to one or more external entities using said data communication channel (The art teaches in Parag. [0022] that one method of calibration involves performing preliminary calibration of a sensor during manufacture of the sensor and storing associated calibration data (data IN) in a calibration table. The calibration data is applied to the output signals of the sensor in order to standardize the sensor output signals (e.g., the sensor response) and to ensure the accuracy of the sensor. In this way, the manufacturing variations of individual sensors and their effects on the responses of these sensors are accounted for).
Claim 3.	Cambou discloses the circuit of Claim 1,
Cambou further discloses wherein the received data IN calibrates said one or more sensors (The art teaches in Parag. [0022] that one method of calibration involves performing preliminary  calibration of a sensor during manufacture of the sensor and storing associated calibration data (data IN) in a calibration table. The calibration data is applied to the output signals of the sensor in order to standardize the sensor output signals (e.g., the sensor response) and to ensure the accuracy of the sensor).
Claim 4. 	Cambou discloses the circuit of Claim 1,
Cambou further discloses wherein the received data IN comprises information leading directly or indirectly to disabling of the PUF circuit (The art teaches in Parag. [0038] that non-sequential extraction of the bit stream (from the calibration table) may further obscure the authorization process, thereby increasing security of the sensor system 400. The PUF challenges are then transferred to the secure terminal 418 and is stored in the secure memory 420 to be used for future authentication of the sensor system 400. Instructions for generating PUF responses are also stored in the secure memory 420. These instructions indicate the order or pattern according to which some or all of the bit stream should be extracted when generating a PUF response to authenticate the sensor system 400. This increases the level of security in case a hacker finds a way through side channel attacks to read the calibration table. With lack of instructions, the hacker faces the difficulty of finding out where to read the responses within the calibration tables, which becomes difficult when the size of the non-volatile memories storing the calibration table is large enough (the instructions (information) is leading indirectly to disabling the circuit, where the hacker won’t be able to read the calibration data (data IN) with lack of instructions)).
Claim 5.	Cambou discloses the circuit of Claim 1,
Cambou further discloses wherein the received data IN, or parts thereof, serves as or contributes to a challenge of the PUF circuit, said circuit providing a response in response to said one or more challenges (The art teaches in Parag. [0039] that PUF challenge data includes both the instructions for PUF response generation and the PUF challenges that were initially generated while setting up the initial cryptographic protocol for the sensor system 400. The instructions are sent to the PUF generator 416, which then extracts one or more PUF responses from the calibration table 408 (data IN) based on the instructions. The PUF generator 416 sends the PUF responses to the secure terminal 418, which compares the PUF responses to the PUF challenges in order to determine if the CPRs match).
Claim 6. 	Cambou discloses the circuit of Claim 1,
Cambou further discloses wherein the received data IN, or parts thereof, signs a challenge of the PUF circuit (The art teaches in Parag. [0039] that PUF challenge data includes both the instructions for PUF response generation and the PUF challenges that were initially generated while setting up the initial cryptographic protocol for the sensor system 400. The instructions are sent to the PUF generator 416, which then extracts one or more PUF responses from the calibration table 408 (data IN) based on the instructions. The PUF generator 416 sends the PUF responses to the secure terminal 418, which compares the PUF responses to the PUF challenges in order to determine if the CPRs match).
Claim 7. 	Cambou discloses the circuit of Claim 2,
Cambou further discloses the circuit wherein said at least one external entities comprise at least one computer or another PUF circuit (The art teaches in Parag. [0038] that system 400 is configured as a single-PUF system that uses only data from the calibration table 408 as a basis for PUF CRP generation, the PUF generator 416 initially generates one or more PUF challenges using the bit stream (data OUT communicated to PUF) of calibration data stored in the calibration table 408. The PUF challenges may be extracted from some or all of the bit stream of the calibration table 408 in any desired order or pattern, not just in the sequential order in which the bit stream is arranged in the calibration table 408).
Claim 8. 	Cambou discloses the circuit of Claim 1,
Cambou further disclose wherein an applied challenge C modifies and/or controls and/or influences communicated data OUT (The art teaches in Parag. [0038] that system 400 is configured as a single-PUF system that uses only data from the calibration table 408 as a basis for PUF CRP generation, the PUF generator 416 initially generates one or more PUF challenges using the bit stream (data OUT) of calibration data stored in the calibration table 408. The PUF challenges may be extracted from some or all of the bit stream of the calibration table 408 in any desired order or pattern, not just in the sequential order in which the bit stream is arranged in the calibration table 408).
Claim 9. 	Cambou discloses the circuit of Claim 1,
Cambou further disclose wherein communicated data OUT modifies an applied challenge C (The art teaches in Parag. [0038] that system 400 is configured as a single-PUF system that uses only data from the calibration table 408 as a basis for PUF CRP generation, the PUF generator 416 initially generates one or more PUF challenges using the bit stream (data OUT) of calibration data stored in the calibration table 408. The PUF challenges may be extracted from some or all of the bit stream of the calibration table 408 in any desired order or pattern, not just in the sequential order in which the bit stream is arranged in the calibration table 408).
Claim 10. 	Cambou discloses the circuit of Claim 1,
Cambou further disclose wherein data IN modifies the response R, while or after the response R is produced (The art teaches in Parag. [0048] that PUF generator extracts PUF responses from a calibration table in the sensor system according to instructions in the PUF challenge data that was received by the PUF generator from the secure terminal at 610. If desired, the PUF responses may be generated based on only a portion of the calibration data (data IN) stored in the calibration table and/or the calibration data used to generate the PUF responses may be read non-sequentially according to an order defined in the instructions).
Claim 11. 	Cambou discloses the circuit of Claim 1,
Cambou further disclose wherein the response R retroacts on data IN (The art teaches in Parag. [0048] that PUF generator extracts PUF responses from a calibration table in the sensor system according to instructions in the PUF challenge data that was received by the PUF generator from the secure terminal at 610. If desired, the PUF responses may be generated based on only a portion of the calibration data (data IN) stored in the calibration table and/or the calibration data used to generate the PUF responses may be read non-sequentially according to an order defined in the instructions).
Claim 12.	 Cambou discloses the circuit of Claim 1,
Cambou further disclose wherein the response R modifies the challenge C (The art teaches in Parag. [0039] that during authentication of the sensor system 400, the secure terminal 418 retrieves PUF challenge data from the secure memory 420. The PUF challenge data includes both the instructions for PUF response generation and the PUF challenges that were initially generated while setting up the initial cryptographic protocol for the sensor system 400. The instructions are sent to the PUF generator 416, which then extracts one or more PUF responses from the calibration table 408 based on the instructions).
Claim 13. 	Cambou discloses a system comprising two or more PUF circuits according to Claim 1,
The PUFs circuit comprising a first PUF circuit and a second PUF circuit (The art teaches in Parag. [0040] that a multi-PUF architecture may be used that uses both the calibration table 408 and the SRAM cache 410 as sources for PUF challenges and PUF responses, rather than the single PUF architecture described above, which only uses the calibration table 408); wherein communicated data OUT of a first circuit is taken as an input data IN by a second circuit (The art teaches in Parag. [0045] that PUF challenge data 502 includes instructions 510 and calibration table based PUF challenges 512. PUF response data 504 includes PUF responses 514 that are generated according to instructions 510 (e.g., at PUF generator 416). The PUF challenges 512 and the PUF responses 514 (data OUT) are fed (taken as an input data IN) into comparator 506 (second circuit) as CRPs. The art teaches in Parag. [0050] that comparator circuitry in the secure terminal compares the PUF responses to corresponding PUF challenges in the PUF challenge data).
Claim 14. 	Cambou discloses a system comprising two or more PUF circuits according to Claim 1,
Cambou further disclose the PUFs circuits comprising a first PUF circuit and a second PUF circuit (The art teaches in Parag. [0040] that a multi-PUF architecture may be used that uses both the calibration table 408 and the SRAM cache 410 as sources for PUF challenges and PUF responses, rather than the single PUF architecture described above, which only uses the calibration table 408); wherein the response R of a first circuit is taken as an input data IN by a second circuit (The art teaches in Parag. [0045] that PUF challenge data 502 includes instructions 510 and calibration table based PUF challenges 512. PUF response data 504 includes PUF responses 514 that are generated according to instructions 510 (e.g., at PUF generator 416). The PUF challenges 512 and the PUF responses 514 are fed (taken as an input data IN) into comparator 506 (second circuit) as CRPs).
Claim 15.	Cambou discloses a system comprising two or more PUF circuits according to Claim 1,
Cambou further disclose the PUFs circuits comprising a first PUF circuit and a second PUF circuit (The art teaches in Parag. [0040] that a multi-PUF architecture may be used that uses both the calibration table 408 and the SRAM cache 410 as sources for PUF challenges and PUF responses, rather than the single PUF architecture described above, which only uses the calibration table 408); wherein communicated data OUT of a first circuit is taken as a challenge C by a second circuit (The art teaches in Parag. [0045] that PUF challenge data 502 includes instructions 510 and calibration table based PUF challenges 512. PUF response data 504 includes PUF responses 514 that are generated according to instructions 510 (e.g., at PUF generator 416). The PUF challenges 512 and the PUF responses 514 (data OUT) are fed into comparator 506 (second circuit) as CRPs. The art teaches in Parag. [0050] that comparator circuitry in the secure terminal compares the PUF responses to corresponding PUF challenges in the PUF challenge data (the data OUT is taken as a challenge for comparison)).
Claim 16.	Cambou discloses a system comprising two or more PUF circuits according to Claim 1,
Cambou further disclose the PUFs circuits comprising a first PUF circuit and a second PUF circuit (The art teaches in Parag. [0040] that a multi-PUF architecture may be used that uses both the calibration table 408 and the SRAM cache 410 as sources for PUF challenges and PUF responses, rather than the single PUF architecture described above, which only uses the calibration table 408); wherein the response R of a first circuit is taken as a challenge C by a second circuit (The art teaches in Parag. [0045] that PUF challenge data 502 includes instructions 510 and calibration table based PUF challenges 512. PUF response data 504 includes PUF responses 514 that are generated according to instructions 510 (e.g., at PUF generator 416). The PUF challenges 512 and the PUF responses 514 are fed into comparator 506 (second circuit) as CRPs. The art teaches in Parag. [0050] that comparator circuitry in the secure terminal compares the PUF responses to corresponding PUF challenges in the PUF challenge data (the response is taken as a challenge for comparison)).
Claim 17. 	Cambou discloses a method for generating a digital signature, the method being implemented by a PUF circuit comprising one or more sensors, the method comprising receiving information about a subset of sensor components of a sensor, applying one or more challenges to the subset of sensor components under uniform conditions, and receiving output signal values from the subset of sensor components, in response to a challenge applied to said subset of sensor components (The art teaches in Parag. [0033] and FIG. 4 a sensor system 400 that can be authenticated using calibration table based PUF challenge-response pairs (CRPs) alone or in combination with SRAM based PUF CRPs. The sensor system 400 includes a sensor 402, an ADC 404, a digital processor 406, a calibration able 408 (The calibration tables each store calibration data for corresponding sensors, see Parag. [0032]), a SRAM cache 410, and a PUF generator 416. The PUF generator 416 is connected to both the digital processor 406 and the calibration table 408. The art teaches in Parag. [0034] that “secure terminal” refers to a device (e.g., computer hardware) connected to a computer network that uses PUF verification (e.g., PUF verification performed using sensor system 400. The art teaches in Parag. [0038] that sensor system 400 is configured as a single-PUF system that uses only data from the calibration table 408 as a basis for PUF CRP generation, the PUF generator 416 initially generates one or more PUF challenges using the bit stream of calibration data stored in the calibration table 408. The sensor system 400 is connected to a secure terminal 418 which is connected to a secure memory 420), wherein method comprises:
determining one or more statistical properties of the noise distribution of said output signal values (The art teaches Parag. [0026] that sensor systems such as the sensor system 100 need to be calibrated with known detectable (e.g., physical or chemical) signals that produce known (i.e., expected) electrical signals when processed by a sensor such as the sensor 102. Possible calibrations may include determining a reset position (i.e. obtaining a zero as an output signal when no detectable signal parameter is sensed) to correct deviations for accurate reading, and to enhance the linearity of the electric signal. Other corrections that may be part of the calibration process include adjusting temperature coefficients, biasing conditions, and cancelling background noise);
receiving input data IN from one or more external data sources using the data communication channel (The art teaches in Parag. [0029] at 230, a processor generates calibration data by comparing the sensor data to the expected results associated with the known detectable signals. The art teaches in Parag. [0030] at 240, the calibration data is stored in a calibration table in non-volatile memory of the sensor system. The processor may be a digital processor that is external to the sensor system (the input data is received from an external data source through a communication channel));
determining a response to the challenge from said statistical properties and selected input data IN received from said one or more external data sources, said response being a digital signature, wherein the input Data IN are used to handle of the PUF circuit (The art teaches in Parag. [0039] that PUF challenge data includes both the instructions for PUF response generation and the PUF challenges that were initially generated while setting up the initial cryptographic protocol for the sensor system 400. The instructions are sent to the PUF generator 416, which then extracts one or more PUF responses (digital signatures) from the calibration table 408 based on the instructions. The art teaches in Parag. [0033] that sensor system 400 that can be authenticated using calibration table based PUF challenge-response pairs (CRPs) alone or in combination with SRAM based PUF CRPs).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure (see PTO-form 892).
The following Patents and Papers are cited to further show the state of the art at the time of Applicant’s invention with respect to Physically Unclonable Functions.
Tuyls (Pub. No. US 2012/0179952); “Physically Unclonable Function with Tamper Prevention and Anti-aging;”
Teaches Methods and systems for configuring computing devices using mobile workspace contexts based on proximity to locations (see Abstract).
Teaches a system for generating an identifying response pattern (see Parag. [0001]).
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.

APPLICANT REBUTTAL: REMARKS Claims 1-18 are pending, with claims 1 and 17 being independent. Claims 1-18 stand rejected. Claims 1-9, 11, and 13-17 are amended herein. Claim 18 is cancelled herein. No new subject matter has been added. Claim Rejections - 35 U.S.C. § 112 Claims 1-18 stand rejected under 35 U.S.C. § 112(b), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter. Office Action, at 2. Applicant has amended the claims to address the rejections under 35 U.S.C. § 112(b), second paragraph. Reconsideration and withdrawal of the rejections is respectfully requested. Claim Rejections - 35 U.S.C. § 101 Claim 18 stands rejected under 35 U.S.C. § 101 for allegedly being directed to non- statutory subject matter. Office Action, at 4. Claim 18 has been cancelled. Claim Rejections - 35 U.S.C. § 102 Claims 1-18 stand rejected under 35 U.S.C. § 102(a)(1) as being anticipated by U.S. Publication No. 2018/0006830 (hereinafter "Cambou"). Office Action, at 4. In order for a reference to anticipate a claim, the reference must teach each and every feature of the claim. Here, the Office Action has not shown that a single reference teaches each and every feature of the claims. Without conceding the propriety of the rejection, Applicant has amended claim 1. Amended independent claim 1 recites, in part, "PUF circuit comprising one or more sensors, the PUF circuit comprising a processor configured to receive information about a subset of sensor components of a sensor, the PUF circuit being configured to apply one or more challenges to the subset of sensor components under uniform conditions, the PUF circuit comprising a receiver configured to receive output signal values from the subset of sensor components, in response to a challenge applied to said subset of sensor components." Support for this amendment to claim 1 can be found throughout Applicant's specification, in at least lines 20-36 of page 5. Independent claim 1 further recites, "the PUF circuit comprises a data communication channel." Support for this amendment to claim 1 can be found throughout Applicant's specification, in at least line 24 of page 7. Support for the feature "one or more statistical properties of the noise distribution of said output signal values," of amended claim 1 can be found throughout Applicant's specification, in at least lines 22 and 30 of page 5 and line 10 of page 6. Support for the feature "determine a response to the challenge from said statistical properties and selected input data IN received from said one or more external data sources, said response being a digital signature," of amended claim 1 can be found throughout Applicant's specification, in at least lines 9-24 of page 14. Support for the feature "wherein the input Data IN are used to handle the PUF circuit" of amended claim 1 can be found throughout Applicant's specification, in at least lines 14-15 of page 13. Similar amendments have been made to independent claim 17. Applicant has also amended the dependent claims. Support for the amendments to claims 2 and 7 can be found throughout Applicant's specification, in at least lines 3-7 of page 10. Amended claim 1 recites, in part, "A PUF circuit . .. [that] comprises a data communication channel, and the PUF circuit is configured to: determine one or more statistical properties of a noise distribution of said output signal values; receive input data IN from one or more external data sources using the data communication channel; [and] determine a response R to said one or more challenges from said statistical properties and said selected input data IN received from said one or more external data sources, said response being a digital signature, wherein the input Data IN are used to handle of the PUF circuit." Cambou does not teach or suggest at least these features of amended independent claim 1. Rather, Cambou describes a solution that intends to improve the cybersecurity of sensor based systems using PUFs and aims to exploit the natural physical variations of sensors, to generate cryptographic physically unclonable functions (PUF). More specifically, Cambou describes a system comprising: a secure terminal having a secure memory that stores PUF challenge data that includes instructions and a set of PUF challenges; a sensor system comprising a sensor operable to measure detectable signals and a calibration table that stores calibration data for the sensor; and a physically unclonable function (PUF) generator connected to the calibration table that receives the PUF challenge data from the secure terminal and that generates a set of PUF responses from the calibration data stored in the calibration table according to the instructions in the PUF challenge data. Cambou's detectable signals are physical signals and chemical signals. Cambou describes a first architecture based on the extraction of a stream of bits from the calibration table of each sensor to generate reference patterns (PUF challenges), which can be stored in secure servers. The authentication of the sensor is positive when the data streams that are generated on demand, called PUF responses, match the challenges. Cambou further describes s a second authentication architecture that is disclosed is based on differential sensors, one of them having the calibration module disconnected. The response to a physical or chemical signal from such a sensor is then used to authenticate a specific pair of sensors. Though Cambou refers to PUF generation using sensors, both the first and the second architecture of Cambou are quite different from amended claim 1. In particular, none of these architectures uses "[a] PUF circuit . .. [that] comprises a data communication channel, and the PUF circuit is configured to: determine one or more statistical properties of a noise distribution of said output signal values; receive input data IN from one or more external data sources using the data communication channel; [and] determine a response R to said one or more challenges from said statistical properties and said selected input data IN received from said one or more external data sources, said response being a digital signature, wherein the input Data IN are used to handle of the PUF circuit," as claimed. The claimed circuit provides a Synthetic PUF (designated in the specification by acronym "SPUF") by using a synthetic or composite assembly of sensors selected for the statistical properties of the distribution of their noise. The above noted features of claim 1 enable the synthetic PUF circuit to produce its response. The synthetic PUF itself stems from a particular selection of available components found in a computer device and from a specific manipulation performed on the statistical properties of the noise distribution of the selection. This enables providing stabilized responses, reinforcing of unclonability, and improved controllability of PUF devices. The skilled person trying to solve such problems would have been incited to implement the method of Cambou, which generates a unique response to a physically unclonable function equipped with challengeable memories using the same challenge signal, thereby not arriving at the claimed circuit. Further, one of ordinary skill in the art would not have been motivated to utilize the teachings of Cambou to solve such problem, as Cambou relates to a totally different PUF architecture. Because the Office Action fails to show that a single reference teaches each and every feature of amended claim 1, amended claim 1 is patentable and the rejection under Section 102 should be withdrawn. Because amended independent claim 17 recites features that are similar, albeit not identical, to the features recited in amended independent claim 1, Applicant submits that independent claim 17 is patentable for at least the same reasons as those submitted for independent claim 1. Because dependent claims 2-17 depend, either directly or indirectly from one of independent claims 1 and 17, they too are patentable for at least the same reasons as claims 1 and 17, as well as for the additional features they recite. Reconsideration and withdrawal of the § 102 rejection of these dependent claims is also respectfully requested. CONCLUSION Applicant respectfully submits that the present application is in condition for allowance. Reconsideration of the application and an early Notice of Allowance are respectfully requested. In the event that the Examiner cannot allow the application for any reason, the Examiner is encouraged to contact Applicant's representative. Date: 12/6/2023SVG {EMBED HERE} 0.122.917Katharine Y. Domitrovich Registration No. 77,712 BakerHostetler 999 Third Avenue Suite 3900 Seattle, WA 98104 Telephone: 206.332.1380 Facsimile: 206.624.7317

NEXT OFFICE ACTION: DETAILED ACTION
Notice of Pre-AIA  or AIA  Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection.  Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on October 25, 2024 has been entered.
Response to Amendment
The amendment filed on September 23, 2024 has been entered.
Claims 1, 7-13, and 17 have been amended.
Claim 2-3 have been canceled.
Claims 19-20 have been added.
Response to Arguments
Applicant’s arguments filed on September 23, 2024 that the prior art of record fails to disclose the subject matter of the independent claims, as amended, are persuasive.
Allowable Subject Matter
Claims 1, 4-8, 10-17, and 19-20 are allowed. The following is the examiner’s statement of reasons for allowance:
In interpreting the currently amended claims, in light of the specification, the Examiner finds the claimed invention to be patentably distinct from the prior art of record.
1/ The closest prior art of Bauer et al. (Patent No. US 10,256,983) discloses: various technologies pertaining to authentication of integrated circuits by using external factors to affect or modify an output of a physically unclonable function (PUF) circuit. In an example, the output of the PUF circuit in response to a challenge signal can be sensitive to changes in environmental factors. In another example, the output of the PUF circuit can be sensitive to user-selectable configuration parameters of the PUF circuit. In yet another example, the output of the PUF circuit can be modified by additional circuitry external to the PUF circuit based upon one or more selectable or configurable inputs. A PUF-based device authentication system that uses external factors as authentication inputs to affect a challenge response of the device authentication system can enhance authentication capabilities by permitting multi-factor authentication (See Abstract).
2/ The closest prior art of Okura et al. (Pub. No. US 2021/0127080) discloses: a solid-state imaging device includes a pixel part, a reading part for reading a pixel signal from the pixel part and a response data generating part including a fuzzy extractor. The response data generating part generates response data including a unique key in association with at least one selected from among variation information of pixels and variation information of the reading part. The response data generating part generates, when regenerating a key, a unique key using helper data acquired in generation of an initial key, variation information acquired in the regeneration of the key, and reliability information determined based on the variation information acquired in the regeneration of the key (See Abstract).
3/ The closest prior art of Flikkema et al. (Pub. No. US 2020/0045033) discloses: a method and system that generates a giant ternary key as a combination of multiple authentication keys such as passwords, pin codes, physically unclonable function (PUF) challenges, or other binary data streams. The longest key is kept as the original binary stream. The following keys are first converted into a decimal data stream and used to insert ternary states inside the original binary stream with an edit distance algorithm. The giant ternary key can be stored in the memory for future authentication. For example, the giant ternary key can be generated, based at least on one or more PUFs embodied in a memory device, as a PUF challenge later used in a challenge response pair to authenticate the memory device. The method reduces the efficiency of sequential attacks because it eliminates partial authentications with a single factor; the entropy of a giant ternary key can be much higher than the entropy of separate binary keys combined (See Parag. [0020]).
The prior art references above, individually or in combination, do not disclose all the claimed limitations. For at least these reasons, claims 1, 4-8, 10-17, and 19-20 are allowed.
Examiner’s amendment
An examiner’s amendment to the record appears below. Should the changes and/or additions be unacceptable to applicant, an amendment may be filed as provided by 37 CFR 1.312. To ensure consideration of such an amendment, it MUST be submitted no later than the payment of the issue fee.
Authorization for this examiner’s amendment was given by Applicant’s representative Katharine Domitrovich Registration No. 77,712.
The application is amended as follows:
1. (Currently amended) A PUF circuit comprising one or more imaging sensors, the PUF circuit comprising a processor configured to receive information about a subset of sensor pixels of an image sensor, the PUF circuit being configured to apply one or more challenges to the subset of sensor pixels under spatially uniform conditions, the PUF circuit comprising a receiver configured to receive output signal values from the subset of sensor pixels, in response to a challenge applied to said subset of sensor pixels, wherein the PUF circuit comprises a bidirectional data communication channel, and the PUF circuit is configured to:
determine one or more statistical moments of a noise distribution of said output signal values;
further receive input data IN through said data communication channel from one or more external data sources using the data communication channel, said data IN relating to an external environment in which the PUF circuit is used;
determine a PUF response R from said one or more statistical moments and said selected input data IN received from said one or more external data sources, said response being a digital signature, wherein the input Data IN are used to handle of the PUF circuit,
wherein the PUF circuit is further configured to communicate data OUT to one or more external entities using said data communication channel, the data OUT being related to internal information of the circuit; and wherein said communicated data OUT is configured to modify an applied challenge C.
2-3. Cancelled.
4. (Previously Presented) The circuit of Claim 1, wherein the received data IN comprises information leading directly or indirectly to disabling of the PUF circuit.
5. (Previously Presented) The circuit of Claim 1, wherein the received data IN, or parts thereof, serves as or contributes to a challenge of the PUF circuit, said circuit providing a response in response to said one or more challenges.
6. (Previously Presented) The circuit of Claim 1, wherein the received data IN, or parts thereof, signs a challenge of the PUF circuit.
7. (Previously Presented) The circuit of Claim 1, wherein said at least one external entities comprise at least one computer or another PUF circuit.
8. (Currently Amended) The circuit of Claim 1, wherein the applied challenge C is configured to modify and/or control and/or influence communicated data OUT.
9. Cancelled.
10. (Previously Presented) The circuit of Claim 1, wherein said data IN is configured to modify the response R, while or after the response R is produced.
11. (Previously Presented) The circuit of Claim 1, wherein the response R is configured to retroact on data IN.
12. (Previously Presented) The circuit of Claim 1, wherein the response R is configured to modify the challenge C.
13. (Currently Amended) A system comprising two or more PUF circuits according to Claim 1, the PUFs circuits comprising a first PUF circuit and a second PUF circuit, wherein the communicated data OUT of the first PUF circuit is taken as an input data IN by the second PUF circuit.
14. (Currently Amended) A system comprising two or more PUF circuits according to Claim 1, the PUFs circuits comprising a first PUF circuit and a second PUF circuit, wherein the response R of the first circuit is taken as an input data IN by the second circuit.
15. (Currently Amended) A system comprising two or more PUF circuits according to Claim 1, the PUFs circuits comprising a first PUF circuit and a second PUF circuit, wherein communicated data OUT of the first circuit is taken as a challenge C by the second circuit.
16. (Currently Amended) A system comprising two or more PUF circuits according to Claim 1, the PUFs circuits comprising a first PUF circuit and a second PUF circuit, wherein the response R of the first circuit is taken as a challenge C by the second circuit.
17. (Currently Amended) A method for generating a digital signature, the method being implemented by a PUF circuit comprising one or more imaging sensors, the method comprising receiving information about a subset of sensor pixels of an imaging sensor, applying one or more challenges to the subset of sensor pixels under spatially uniform conditions, and receiving output signal values from the subset of sensor pixels, in response to a challenge applied to said subset of sensor pixels, wherein the PUF circuit comprises a bidirectional data communication channel, and
wherein the method comprises:
determining one or more statistical properties of a noise distribution of said output signal values;
receiving input data IN from one or more external data sources, through said data communication channel, said data IN relating to an external environment in which the PUF circuit is used;
determining a PUF response R from said one or more statistical properties and selected input data IN received from said one or more external data sources, said response being a digital signature,
wherein the input Data IN are used to handle of the PUF circuit,
wherein the method comprises communicating data OUT to one or more external entities using said data communication channel, the data OUT being related to internal information of the circuit; and wherein said communicated data OUT is configured to modify an applied challenge C.
18. Cancelled.
19. (Currently Amended) The circuit of claim 1, wherein the processor is configured to determine the statistical moment of order i of a temporal distribution of the output signal value of the each sensor pixel, the processor being further configured to determine one or more an identifier from the determined outliers' pixels.
20. (Currently Amended) The circuit of claim 1, wherein the processor is configured to:
for each pixel of the subset of sensor pixels, determine the statistical moment of order i of a temporal distribution of the output signal value of each sensor pixel; and
determine one or more pathological sensor pixels, the pathological pixels being pixels whose sum of statistical moment values of the two temporal distributions associated to the pixels obtained when challenging the subset of sensor pixels under uniform conditions,
the processor being further configured to generate an identifier from the determined pathological sensor pixels.
Conclusion

CITED REFERENCE SUMMARIES: Ref US20180006830A1: Claims:
A system comprising: a secure terminal having a secure memory that stores PUF challenge data that includes instructions and a set of PUF challenges; and a sensor system comprising: a sensor operable to measure detectable signals; a calibration table that stores calibration data for the sensor; and a physically unclonable function (PUF) generator connected to the calibration table that receives the PUF challenge data from the secure terminal and that generates a set of PUF responses from the calibration data stored in the calibration table according to the instructions in the PUF challenge data.
a secure terminal having a secure memory that stores PUF challenge data that includes instructions and a set of PUF challenges; and
a sensor system comprising: a sensor operable to measure detectable signals; a calibration table that stores calibration data for the sensor; and a physically unclonable function (PUF) generator connected to the calibration table that receives the PUF challenge data from the secure terminal and that generates a set of PUF responses from the calibration data stored in the calibration table according to the instructions in the PUF challenge data.
a sensor operable to measure detectable signals;
a calibration table that stores calibration data for the sensor; and
a physically unclonable function (PUF) generator connected to the calibration table that receives the PUF challenge data from the secure terminal and that generates a set of PUF responses from the calibration data stored in the calibration table according to the instructions in the PUF challenge data.
The system of claim 1 , wherein the detectable signals are selected from the group consisting of physical signals and chemical signals.
The system of claim 1 , wherein the secure terminal includes comparator circuitry that compares the set of PUF responses to the set of PUF challenges to determine a rate at which the set of PUF responses and the set of PUF challenges match.
The system of claim 3 , wherein the comparator circuitry comprises exclusive-OR logic gates.
The system of claim 3 , wherein the secure terminal authenticates the sensor system when the secure terminal determines that the rate at which the set of PUF responses and the set of PUF challenges match is at or above a predetermined threshold.
The system of claim 3 , wherein the sensor system further comprises: a random access memory (RAM) cache comprising a plurality of RAM cells.
a random access memory (RAM) cache comprising a plurality of RAM cells.
The system of claim 6 , wherein the PUF generator generates an additional set of PUF responses based on a percentage of the plurality of RAM cells that are in an ON state after powering on the RAM cache.
The system of claim 7 , wherein the PUF challenge data includes an additional set of PUF challenges, and wherein the comparator circuitry compares the additional set of PUF responses to the additional set of PUF challenges to determine an additional rate at which the additional set of PUF responses and the additional set of PUF challenges match.
The system of claim 8 , wherein the secure terminal authenticates the sensor system when the secure terminal determines that the rate at which the set of PUF responses and the set of PUF challenges match is at or above a predetermined threshold and that the additional rate at which the additional set of PUF responses and the additional set of PUF challenges match is at or above the predetermined threshold.
A system comprising: a signal source that produces detectable signals; a secure terminal having a secure memory that stores physically unclonable function (PUF) challenge data; and a sensor system comprising: a calibration table that stores calibration data; a first sensor that converts the detectable signals into calibrated sensor data according to the calibration data; a second sensor that converts the detectable signals into uncalibrated sensor data; and a PUF generator that generates PUF responses by performing logical exclusive-or (XOR) operations on the calibrated sensor data and the uncalibrated sensor data, wherein the secure terminal compares the PUF responses to corresponding PUF challenges in the PUF challenge data to authenticate the sensor system.
a signal source that produces detectable signals;
a secure terminal having a secure memory that stores physically unclonable function (PUF) challenge data; and
a sensor system comprising: a calibration table that stores calibration data; a first sensor that converts the detectable signals into calibrated sensor data according to the calibration data; a second sensor that converts the detectable signals into uncalibrated sensor data; and a PUF generator that generates PUF responses by performing logical exclusive-or (XOR) operations on the calibrated sensor data and the uncalibrated sensor data, wherein the secure terminal compares the PUF responses to corresponding PUF challenges in the PUF challenge data to authenticate the sensor system.
a calibration table that stores calibration data;
a first sensor that converts the detectable signals into calibrated sensor data according to the calibration data;
a second sensor that converts the detectable signals into uncalibrated sensor data; and
a PUF generator that generates PUF responses by performing logical exclusive-or (XOR) operations on the calibrated sensor data and the uncalibrated sensor data, wherein the secure terminal compares the PUF responses to corresponding PUF challenges in the PUF challenge data to authenticate the sensor system.
The system of claim 10 , wherein the detectable signals are selected from the group consisting of physical signals and chemical signals.
The system of claim 10 , wherein the secure terminal includes a comparator, and wherein comparing the PUF responses to the corresponding PUF challenges is performed by the comparator to determine a rate at which the PUF responses and the corresponding PUF challenges match.
The system of claim 12 , wherein the comparator circuitry comprises exclusive-OR logic gates.
The system of claim 12 , wherein the secure terminal authenticates the sensor system when the secure terminal determines that the rate at which the PUF responses and the corresponding PUF challenges match is at or above a predetermined threshold.
A method for authenticating a sensor system comprising: with a secure terminal, issuing physically unclonable function (PUF) challenge data to the sensor system; with a PUF generator in the sensor system, generating PUF responses from calibration data in a calibration table in the sensor system; with the PUF generator, sending the PUF responses to the secure terminal; and with the secure terminal, comparing the PUF responses with corresponding PUF challenges in the PUF challenge data to determine a rate at which the PUF responses and the corresponding PUF challenges match.
with a secure terminal, issuing physically unclonable function (PUF) challenge data to the sensor system;
with a PUF generator in the sensor system, generating PUF responses from calibration data in a calibration table in the sensor system;
with the PUF generator, sending the PUF responses to the secure terminal; and
with the secure terminal, comparing the PUF responses with corresponding PUF challenges in the PUF challenge data to determine a rate at which the PUF responses and the corresponding PUF challenges match.
The method of claim 15 , further comprising: with the secure terminal, authenticating the sensor system when the rate at which the PUF responses and the corresponding PUF challenges match is at or above a predetermined threshold.
with the secure terminal, authenticating the sensor system when the rate at which the PUF responses and the corresponding PUF challenges match is at or above a predetermined threshold.
The method of claim 16 , wherein the PUF challenge data further comprises instructions, wherein the PUF responses are generated according to the instructions in the PUF challenge data.
The method of claim 16 , wherein the calibration data is for calibrating the output of a sensor in the sensor system.
The method of claim 16 , wherein comparing the PUF responses with the corresponding PUF challenges in the PUF challenge data to determine the rate at which the PUF responses and the corresponding PUF challenges match further comprises: with exclusive-OR (XOR) logic in comparator circuitry in the secure terminal, comparing the PUF responses with the corresponding PUF challenges in the PUF challenge data by performing XOR logic operations on the PUF responses and the corresponding PUF challenges to determine the rate at which the PUF responses and the corresponding PUF challenges match
with exclusive-OR (XOR) logic in comparator circuitry in the secure terminal, comparing the PUF responses with the corresponding PUF challenges in the PUF challenge data by performing XOR logic operations on the PUF responses and the corresponding PUF challenges to determine the rate at which the PUF responses and the corresponding PUF challenges match
The method of claim 15 , further comprising: with the PUF generator, generating additional PUF responses based on a percentage of random access memory (RAM) cells in a RAM cache that are in an ON state when the RAM cache is powered on; with the secure terminal, comparing the additional PUF responses with corresponding additional PUF challenges in the PUF challenge data to determine an additional rate at which the PUF responses and the corresponding PUF challenges match; and with the secure terminal, authenticating the sensor system when the rate at which the PUF responses and the corresponding PUF challenges match and the additional rate at which the PUF responses and the corresponding PUF challenges match are each at or above a predetermined threshold.
with the PUF generator, generating additional PUF responses based on a percentage of random access memory (RAM) cells in a RAM cache that are in an ON state when the RAM cache is powered on;
with the secure terminal, comparing the additional PUF responses with corresponding additional PUF challenges in the PUF challenge data to determine an additional rate at which the PUF responses and the corresponding PUF challenges match; and
with the secure terminal, authenticating the sensor system when the rate at which the PUF responses and the corresponding PUF challenges match and the additional rate at which the PUF responses and the corresponding PUF challenges match are each at or above a predetermined threshold.
Ref US20120179952A1: Claims:
A system for generating an identifying response pattern comprising a memory used as a physically unclonable function comprising a plurality of re-writable memory locations each memory location having at least two possible logical states, and an input for receiving an activation signal so as to cause each of said memory locations to enter one of its possible logical states, the entered state being dependent on physical, at least partially random characteristics of said memory, and thereby generating a response pattern of logical states useful for identifying the system, the generation of the response pattern is sensitive to degradation after repeated applications of the activation signal, a memory-overwriting device configured for overwriting at least a first portion of the plurality of memory locations to obscure the response pattern in the memory, and an anti-degradation device configured to write to each respective location of a second portion of the plurality of memory locations an inverse of a logical state previously read from the respective location of the second portion.
a memory used as a physically unclonable function comprising a plurality of re-writable memory locations each memory location having at least two possible logical states, and an input for receiving an activation signal so as to cause each of said memory locations to enter one of its possible logical states, the entered state being dependent on physical, at least partially random characteristics of said memory, and thereby generating a response pattern of logical states useful for identifying the system, the generation of the response pattern is sensitive to degradation after repeated applications of the activation signal,
a memory-overwriting device configured for overwriting at least a first portion of the plurality of memory locations to obscure the response pattern in the memory, and
an anti-degradation device configured to write to each respective location of a second portion of the plurality of memory locations an inverse of a logical state previously read from the respective location of the second portion.
A system for generating an identifying response pattern as in claim 1 comprising a helper data memory, the helper data memory comprising error-correcting data for correcting deviations between the entered logical states and logical states previously read from the plurality of memory locations, wherein the memory-overwriting device is configured for overwriting the helper data memory.
A system for generating an identifying response pattern as in claim 1 comprising a tampering flag and wherein the memory-overwriting device is configured for overwriting conditionally upon the tampering flag being set.
A system for generating an identifying response pattern as in claim 1 , wherein the memory-overwriting device is configured for overwriting the first portion of the plurality of memory locations with a sequence of random values.
A system for generating an identifying response pattern as in claim 1 , comprising an exclusive-or device, wherein the memory-overwriting device is configured to obscure the response pattern in the memory by writing to the respective locations of the first portion of the plurality of memory locations an exclusive- or of the respective location's entered state and a respective value from a sequence of random values.
A system for generating an identifying response pattern as in claim 4 or 5 , wherein the first portion of the plurality of memory locations and/or at least part of the sequence of random values is obtained by applying a pseudorandom function ( 150 ) to a fixed random-number seed.
A system for generating an identifying response pattern as in claim 6 wherein at least part of the sequence of random values is true random.
A system for generating an identifying response pattern as in claim 7 , wherein the random-number seed is dependent upon the identifying response pattern.
A system for generating an identifying response pattern as in claim 1 , comprising a helper data memory, the helper data memory comprising error-correcting data for correcting deviations between the entered logical states and logical states previously read from the plurality of memory locations, and an enrollment-string reconstruction device to reconstruct the logical states previously read from the plurality of memory locations configured to apply an error-correcting function to the error-correcting data and to the entered logical states to correct deviations between the entered logical states and the logical states previously read,
a helper data memory, the helper data memory comprising error-correcting data for correcting deviations between the entered logical states and logical states previously read from the plurality of memory locations, and
an enrollment-string reconstruction device to reconstruct the logical states previously read from the plurality of memory locations configured to apply an error-correcting function to the error-correcting data and to the entered logical states to correct deviations between the entered logical states and the logical states previously read,
wherein the anti-degradation device is configured to write to each respective location of the second portion of the plurality of memory locations an inverse of the reconstructed logical state previously read from the respective location of the second portion.
A system for generating an identifying response pattern as in claim 1 , comprising a temperature-sensor, wherein the anti-degradation device is configured to write to the second portion conditionally upon a temperature measurement of the temperature-sensor being above a predetermined upper temperature threshold, or, the memory-overwriting device is configured for overwriting at least a first portion of the plurality of memory locations conditionally upon a temperature measurement of the temperature-sensor being below a predetermined lower temperature threshold.
the anti-degradation device is configured to write to the second portion conditionally upon a temperature measurement of the temperature-sensor being above a predetermined upper temperature threshold, or,
the memory-overwriting device is configured for overwriting at least a first portion of the plurality of memory locations conditionally upon a temperature measurement of the temperature-sensor being below a predetermined lower temperature threshold.
A system for generating an identifying response pattern as in claim 1 , wherein the memory-overwriting device comprises a tuning parameter input for receiving a tuning parameter, the memory-overwriting device being configured to set the proportion between the number of locations in the first portion and the number of locations in the second portion in dependency upon the tuning parameter.
A system for generating an identifying response pattern as in claim 12 , wherein the tuning parameter is temperature dependent.
A method of generating an identifying response pattern from a memory used as a physically unclonable function, the memory comprising a plurality of re-writable memory locations each memory location having at least two possible logical states, wherein the generation of the response pattern is sensitive to degradation after repeated applications of the activation signal,
the method comprising applying an activation signal to an input of the memory so as to cause each of said memory locations to enter one of its possible logical states, the entered state being dependent on physical, at least partially random characteristics of said memory, and thereby generating the response pattern of logical states useful for identifying the memory, reading out the response pattern from the memory,
applying an activation signal to an input of the memory so as to cause each of said memory locations to enter one of its possible logical states, the entered state being dependent on physical, at least partially random characteristics of said memory, and thereby generating the response pattern of logical states useful for identifying the memory,
reading out the response pattern from the memory,
wherein the method further comprises overwriting at least a first portion of the plurality of memory locations to obscure the response pattern in the memory, writing to each respective location of a second portion of the plurality of memory locations an inverse of a logical state previously read from the respective location of the second portion.
overwriting at least a first portion of the plurality of memory locations to obscure the response pattern in the memory,
writing to each respective location of a second portion of the plurality of memory locations an inverse of a logical state previously read from the respective location of the second portion.
A method of generating a response as in claim 14 , comprising obtaining a temperature measurement, and wherein the writing to each respective location of a second portion of the plurality of memory locations is done conditionally upon the temperature measurement being above a predetermined temperature threshold, or the overwriting of at least a first portion of the plurality of memory locations is done conditionally upon the temperature measurement being below a predetermined lower temperature threshold.
the writing to each respective location of
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