# US 12,003,631 B2 · Unique identifiers based on quantum effects > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,003,631 B2 - Document ID: US12003631B2 - Status: Granted - Kind: B2 - Application number: 18/118,694 - Filed: 2023-03-07 - Published: 2023-11-02 - Granted: 2024-06-04 - Earliest claimed: 2017-10-17 - Assignees: Crypto Quantique Limited - Applicants: Crypto Quantique Limited - Inventors: Shahram Mossayebi; Patrick Camilleri; Henry Edward William Montagu - Web page: https://patentgrep.com/patent/US12003631B2 ## CPC - H04L 9/0866: {involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics} - G06F 7/588: {Random number generators, i.e. based on natural stochastic processes} - G09C 1/00: Apparatus or methods whereby a given sequence of signs, e.g. an intelligible text, is transformed into an unintelligible sequence of signs by transposing the signs or groups of signs or by replacing them by others according to a predetermined system (cryptographic typewriters G09C3/00) - H04B 10/07: Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems - H04L 9/0852: {Quantum cryptography (transmission systems employing electromagnetic waves other than radio waves, e.g. light, infrared H04B10/00; wavelength-division multiplex systems H04J14/02; WDM arrangements H04J14/03)} - H04L 9/3278: {using physically unclonable functions [PUF]} - H10H 20/812: within the light-emitting regions, e.g. having quantum confinement structures - H10W 42/405: {using active circuits} - G06N 7/01: Probabilistic graphical models, e.g. probabilistic networks - H10D 30/6891: {characterised by the shapes, relative sizes or dispositions of the floating gate electrode} - H10D 48/383: {Quantum effect devices, e.g. of devices using quantum reflection, diffraction or interference effects} - H10D 62/814: {Quantum box structures} - 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) - G09C: CIPHERING OR DECIPHERING APPARATUS FOR CRYPTOGRAPHIC OR OTHER PURPOSES INVOLVING THE NEED FOR SECRECY - H04B: TRANSMISSION - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract A method is provided for determining a unique identifier of a device, the device including a quantum tunnelling barrier unique to the device. The method comprises applying a potential difference across the quantrum tunnelling barrier, the potential difference sufficient to enable tunnelling barrier. The method further comprises measuring an electrical signal, the electrical signal representative of a tunnelling current through the quantrum tunnelling barrier. The method further comprises determining, from the measured electrical signal, a unique identifier for the device. Related apparatuses, systems, computer-readable media and methods are also provided herein. ## Claims ### Claim 1 A method for determining a unique identifier of a device, the device including a unique quantum tunnelling barrier, the method comprising: applying a potential difference across the quantum tunnelling barrier, the potential difference sufficient to enable tunnelling of charge carriers through the quantum tunnelling barrier; measuring an electrical signal representative of a characteristic of the tunnelling of charge carriers through the quantum tunnelling barrier; and determining, from the measured electrical signal, a unique identifier for the device. ### Claim 2 (depends on 1) The method according to claim 1, wherein the device includes a single quantum tunnelling barrier. ### Claim 3 (depends on 1) The method according to claim 1, wherein the quantum tunnelling barrier has an average thickness of less than or equal to five nanometres. ### Claim 4 (depends on 1) The method according to claim 1, further comprising providing the unique identifier for use in a communication protocol or a data transaction, optionally in encrypting or authenticating an aspect thereof, and/or providing the unique identifier as a digital identifier of a physical object or a digital object. ### Claim 5 (depends on 1) The method according to claim 1, further comprising using the unique identifier in a communication protocol or a data transaction and/or using the unique identifier as a digital identifier of a physical object or a digital object. ### Claim 6 (depends on 1) The method according to claim 1, wherein the characteristics of the quantum tunnelling barrier revealed by the measured electrical signal result from one or more distinctive nanoscale properties of the device that arise from device-to-device variability between ostensibly identical devices produced by the same semiconductor manufacturing process. ### Claim 7 (depends on 6) The method according to claim 6, wherein the distinctive nanoscale properties that are variable from device-to-device are beyond the control of a semiconductor manufacturing process used to produce the device. ### Claim 8 (depends on 1) The method according to claim 1, further comprising: applying a same potential difference across the quantum tunnelling barrier of an ostensibly identical second device, measuring an electrical signal representative of a second tunnelling current through the second quantum tunnelling barrier, and determining a second unique identifier for the ostensibly identical second device, wherein the electrical signals are representative of tunnelling currents through the quantum tunnelling barrier of the ostensibly identical first and second devices are different. ### Claim 9 (depends on 1) The method according to claim 1, further comprising comparing the unique identifier of the device with a database containing the unique identifier for the device and unique identifiers for other devices, wherein each of the other devices includes a quantum tunnelling barrier unique to that other device. ### Claim 10 (depends on 1) The method according to claim 1, further comprising, prior to applying the potential difference, receiving a challenge from a third party. ### Claim 11 (depends on 10) The method according to claim 10, further comprising communicating the unique identifier to the third party in response to the challenge. ### Claim 12 (depends on 1) The method according to claim 1, wherein the device comprises a physically unclonable function, and wherein the unique identifier is a unique identifier of the physically unclonable function. ### Claim 13 (depends on 1) The method according to claim 1, wherein determining a unique identifier for the device comprises determining a mean value of the tunnelling current. ### Claim 14 (depends on 1) The method according to claim 1, wherein measuring an electrical signal comprises measuring an electrical signal multiple times, and wherein determining a unique identifier for the device comprises interpolating a current spectrum from the multiple measurements of the electrical signal. ### Claim 15 (depends on 1) A non-transitory computer readable medium having instructions stored thereon which, when executed by a processor, cause the processor to determine a unique identifier of a device by performing a method according to claim 1. ### Claim 16 A device comprising: a first terminal and a second terminal; a quantum tunnelling barrier unique to the device, the quantum tunnelling barrier located between the first terminal and the second terminal; and a processor configured to: apply a potential difference between the first terminal and the second terminal and across the quantum tunnelling barrier, the potential difference sufficient to enable tunnelling of charge carriers through the quantum tunnelling barrier; measure an electrical signal representative of the tunnelling of charge carriers through the quantum tunnelling barrier; and determine, from the measured electrical signal, a unique identifier for the device. ### Claim 17 (depends on 16) The device according to claim 16, wherein the device comprises a complementary metal-oxide-semiconductor, CMOS, chip. ### Claim 18 (depends on 16) The device according to claim 16, wherein the device comprises a single unique quantum tunnelling barrier. ### Claim 19 (depends on 16) The device according to claim 16, wherein the quantum tunnelling barrier has an average thickness of less than or equal to five nanometres. ### Claim 20 (depends on 16) The device according to claim 16, wherein the device further comprises a power supply for applying the potential difference.