Device for detecting manipulation on a quantum random number generator

Abstract

The invention relates to a device (10) for detecting manipulation on a quantum random number generator, comprising: a quantum random number generator (20) having a semiconductor substrate (22) which comprises an entropy source (24) in the form of a photon source (26), and a detector (28) which is designed to detect radiation emitted from the entropy source (24); and a manipulation detector (30) which is designed to detect radiation that is detectable by the detector (28). The manipulation detector (30) is located in the surroundings of the detector (28). It is shielded with respect to the entropy source (24) in such a way that only radiation from outside the entropy source (24) can be detected.

Description

[0001] Device for detecting manipulation of a quantum random number generator

[0002] The present invention relates to a device for detecting manipulation of a quantum random number generator, an integrated circuit comprising such a device, a network comprising a plurality of quantum random number generators and a corresponding method.

[0003] In today's world, the secure and reliable generation of true random numbers is becoming increasingly important, especially for encryption and cryptography, but also in networks or distributed networks without a central control authority. Security today often depends directly on the quality and unpredictability of random numbers. This is especially true for encryption, authentication, and other security-relevant operations. Random number generators must therefore generate completely unpredictable sequences, with quantum mechanisms and the generation of photons being among the best methods. For example, DE 10 2022 125 572 A1 discloses a computer that includes at least one quantum process-based generator for true random numbers (QRNG) as a random number generator with a high random bit output rate, particularly for encryption.

[0004] Random number generators, and especially quantum random number generators (QRGNs), often represent an interesting and worthwhile target for attacks and cyberattacks. They must therefore be particularly resistant to manipulation from outside or by third parties.

[0005] To increase security, quantum random number generators (QRNGs) are used. These comprise an entropy source, which is a photon source, and a detector in a semiconductor substrate. The entropy source and detector are arranged perpendicular to each other and to a surface of the semiconductor substrate, enabling a particularly high random number data rate. Such quantum random number generators, with a vertical arrangement in the semiconductor substrate, guarantee that the generated random numbers are truly random, unpredictable, and of high entropy. "Entropy" refers to the uncertainty or information contained in a random number and represents the degree of unpredictability. This can be verified using a guideline developed by the National Institute of Standards and Technology (NIST), NIST SP800-22.

[0006] Quantum random number generators (QRNGs) are preferably constructed monolithically and integrally within the semiconductor substrate. In addition to the entropy source (photon source) and the detector, further elements are present in the semiconductor substrate. These may include: one or more analog amplifiers and / or filter circuits for conditioning the output signal of the entropy source for subsequent analog-to-digital conversion; a single- or multi-bit analog-to-digital converter (ADC), which in the case of a single-bit analog-to-digital converter may be a comparator; one or more time-to-digital converters (TDCs) and / or one or more time-to-pseudo-random number converters (TPRNCs) for assigning a unique binary number to a time interval between two pulses of the entropy source; one or more entropy extraction devices for extracting one or more random bits from these binary numbers;one or more finite state machines for converting the data stream of random bits into random numbers; one or more interfaces for accessing these random numbers by one or more external computer systems and / or for controlling the quantum random number generator; one or more components or elements for carrying out and / or supporting a health check of one or more of the elements and / or their interaction; one or more elements for generating the internal operating voltages within the quantum random number generator for operating the various elements or components of the quantum random number generator.

[0007] Such or similar quantum random number generators (quantum-based random number generators), which can be used in the context of the invention, are known, for example, from DE 10 2023 126 168 A1 or WO 2024 / 074170 A1. Quantum random number generators for generating random numbers based on optical methods with one or more SPADs (Single Photon Avalanche Diodes) as detectors are also known from Francesco Ceccarelli et al.; "Recent Advances and Future Perspectives of Single-Photon Avalanche Diodes for Quantum Photonics Applications"; Adv. Quantum Technol. 2021, 4, 2000102.

[0008] The possibility of disrupting and influencing a quantum random number generator using external light, thus enabling manipulation or prediction of the random numbers, was demonstrated, for example, in Juan Carlos Garcia-Escartin, et al.; "Attacking quantum key distribution by light injection via ventilation openings"; PLOS ONE | https: / / doi.orq / 10.1371 / iournal.pone.0236630; August 3, 2020.

[0009] Options for detecting such attacks usually include start-up, live, and total-failure tests. The start-up test checks whether all components are functioning properly when the QRNG is powered on. The live test verifies the quality of the random numbers using statistical tests during operation of the QRNG. The total-failure test detects a total failure of the QRNG's entropy source or detector. Such tests are described in Werner Schindler et al.; "Evaluation Criteria for True (Physical) Random Number Generators Used in Cryptographic Applications"; B.S. Kaliski Jr. et al. (Eds.): CHES 2002, LNCS 2523, pp. 431-449, 2003. There is still a great need to improve the security of quantum random number generators that use an entropy or photon source and to make them robust against external interference, in particular against interference from radiation or optical interference via photon radiation.

[0010] The object is achieved by a device having the features of claim 1, by an integrated circuit (IC) having the features of claim 19, a network having the features of claim 22 and by a method having the features of claim 23.

[0011] In one aspect, the present invention relates to a device for detecting tampering with a quantum random number generator (QRNG), comprising a quantum random number generator with a semiconductor substrate and a tamper detector. The quantum random number generator has a semiconductor substrate that includes an entropy source and a detector. The entropy source is a photon source. The detector is designed and configured to detect radiation emitted by the entropy source. The emitted radiation can, for example, be photon radiation. However, the radiation can also consist of individual photons, so that the receiver is designed accordingly, i.e., is suitable for detecting individual photons.

[0012] The tamper detector is designed to detect radiation that can be detected by the QRNG's detector. Accordingly, the tamper detector can detect photon radiation and / or individual photons.

[0013] The entropy source and detector are preferably vertically integrated such that the entropy source radiates perpendicularly to a surface of the semiconductor substrate. Viewed from the surface, the entropy source is preferably closer to the surface than the detector. The entropy source faces away from the surface, so that it radiates toward the detector. This results in a vertical arrangement of entropy source and detector, with the detector positioned below the entropy source.

[0014] According to the invention, the tamper detector is arranged in the vicinity of the detector. The distances to the detector are preferably in the micrometer range (pm range), particularly preferably in the range of less than 100 pm, less than 50 pm, less than 20 pm, less than 10 pm, less than 5 pm.

[0015] The tamper detector is shielded from the entropy source in such a way that only radiation from outside the entropy source is detectable. The tamper detector is thus shielded in such a way that no radiation from the entropy source is measured by the tamper detector. The tamper detector's detection is therefore free from radiation, photons, or single photons emitted by the entropy source. This ensures that the tamper detector does not measure the radiation emitted by the entropy source, but rather other radiation that reaches the quantum random number generator from outside the entropy source, preferably from outside the quantum random number generator. Thus, the tamper detector can be used to detect external radiation and influences based on radiation, in particular electromagnetic radiation, especially visible or invisible light.

[0016] In a further aspect, the invention relates to an integrated circuit comprising a semiconductor substrate in which a quantum random number generator is arranged, comprising an entropy source configured as a photon source, and comprising a detector for detecting radiation from the photon source. The integrated circuit (IC) has a tamper detector configured and configured to detect radiation to which the detector of the quantum random number generator is sensitive. The tamper detector is arranged in the vicinity of the detector and is shielded from the entropy source such that no radiation from the entropy source is detected. Detection by the tamper detector is therefore free of radiation from the entropy source. Only radiation other than that from the entropy source is detected.Thus, for example, external radiation, interference, or other radiation-like influences acting on the integrated circuit can be detected. The integrated circuit (IC) can comprise a quantum random number generator and a tamper detector as described above. The IC can therefore be a particular embodiment of the inventive device described above.

[0017] In a further aspect, the invention relates to a network with multiple quantum random number generators and at least one tamper detector. Each of the quantum random number generators has a semiconductor substrate, which has a photon source designed as an entropy source, and a detector. The detector is designed to detect radiation emitted by the entropy source. The tamper detector is designed to detect radiation that is detectable by the detector of the random number generator. Furthermore, the tamper detector is shielded from entropy sources of the quantum random number generators of the network. In this way, radiation applied to the network from the outside, which is free of radiation components or radiation from the quantum random number generators, is detected. Several random number generators can share a tamper detector.

[0018] Of course, it is possible to provide multiple tamper detectors in the network, with some or all of them being integrated into the quantum random number generator, e.g., in the semiconductor substrate of the quantum random number generator. Shielding the tamper detector against radiation from the entropy sources can be achieved by means of shielding elements, such as metal sheets or metallized surfaces, or by a suitable spatial arrangement, for example, a suitable spatial arrangement within the semiconductor substrate. The network can thus comprise multiple devices according to the invention or parts of the devices and a common tamper detector.A further aspect relates to a QRNG, a corresponding method, a method configured according to the device, a vehicle, and a computer program product with program code for performing the steps of the method when the program code is executed on a computer or a microprocessor. A vehicle and a device according to the invention form a system for detecting manipulation of a quantum random number generator.

[0019] Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those to be explained below can be used not only in the respective combinations specified, but also in other combinations or alone, without departing from the scope of the present invention. In particular, the method and the computer program product can be implemented according to the embodiments described for the device in the dependent claims.

[0020] According to the invention, the device detects manipulation of a quantum random number generator caused by external influences, i.e., from outside the random number generator. In particular, interference caused by interference radiation, in particular electromagnetic radiation and / or photon radiation and / or light radiation in the visible or invisible range, is detected. This is particularly possible if the manipulation detector is sensitive not only to the type of radiation detectable by the detector of the quantum random number generator, but also to other radiation. This can be achieved by appropriately selecting the type and nature of the manipulation detector, by setting an operating mode, or by selecting the detector voltage.

[0021] The tamper detector can also be arranged outside the quantum random number generator. It can be a single, separate component. Alternatively, and preferably, it is integrated into the quantum random number generator, in any case into the semiconductor substrate of the generator. The tamper detector is preferably monolithic, just as the quantum random number generator can be monolithic. The entropy source or photon source can be designed as a Si diode or a Zener diode. The entropy source is preferably a planar Zener diode, for example, a Si LED, arranged above the detector. The detector is preferably a planar SPAD.In the QRNG, a vertical integration of the entropy source and the detector can preferably be designed such that the entropy source radiates perpendicular to a surface of the semiconductor substrate, preferably away from the surface, so that a detector arranged below the entropy source can be designed, for example, as a SPAD or DeepSPAD and a compact design can be realized.

[0022] In a preferred embodiment of the device, the manipulation detector is shielded from the entropy source by arranging the manipulation detector relative to the entropy source. This arrangement is such that no radiation from the entropy source reaches the manipulation detector. Alternatively, and equally preferably, the manipulation detector is shielded by a shielding element arranged between the manipulation detector and the entropy source. The arrangement is also such that no radiation from the entropy source reaches the manipulation detector, and consequently, no radiation from the entropy source can be detected by the manipulation detector.

[0023] The shielding of the tamper detector thus causes a shadow region of the entropy source to be exploited or created. The shadow region of the entropy source is the region that is free of radiation from the entropy source. In this region, no radiation from the entropy source can be detected. According to the preferred embodiment, the tamper detector is arranged in this shadow region. The shadow region can be intrinsic to the entropy source, i.e., it can exist on its own. This can be achieved, for example, by arranging the individual doping areas within the semiconductor substrate and by a corresponding arrangement of the tamper detector in the semiconductor substrate. Alternatively, the shadow region can also be created by means of a shield or a shielding element, thus creating the shadow region artificially.

[0024] The shielding of the tamper detector ensures that any detection of radiation by the tamper detector is free from radiation originating from the entropy source or the photon source. The reception of radiation from the entropy source is thus excluded by the shielding. This is particularly true if the tamper detector is located in the shadow area of ​​the entropy source, where the shadow area is predetermined by the photon source or created by a shielding element.

[0025] In a further preferred embodiment, the tamper detector is a photodiode or an avalanche diode. The tamper detector is preferably a single-photon avalanche diode (SPAD), which makes it possible to detect even single photons. In further, equally preferred embodiments, the tamper detector is designed as a "deep SPAD," or as an n-SPAD, or as a p-SPAD. An n-SPAD has a corresponding near-surface n-doping; a p-SPAD has a corresponding near-surface p-doping. In this way, different sensitivities can be created, particularly for different wavelength ranges of light. For example, a p-SPAD is highly sensitive to high-energy radiation, particularly blue or green light. An n-SPAD is sensitive to low-energy radiation. It therefore reacts sensitively to red light or infrared light.

[0026] A "deepSPAD" is an arrangement of an avalanche diode in the semiconductor substrate, as described, for example, in DE 10 2023 126 168 A1. Such a design is also preferably used for the detector of the quantum random number generator.

[0027] In a further embodiment, the tamper detector is integrated into the semiconductor substrate of the quantum random number generator. It can be arranged next to the detector or at the same height as the detector. A same height is characterized by the same vertical distance to the surface of the semiconductor substrate. The distance in the horizontal direction, i.e., parallel to the surface of the semiconductor substrate, can vary and depend on the spatial conditions or other requirements. In particular, the distance between the tamper detector and the detector can be chosen to be large enough that the tamper detector is arranged in the shadow area of ​​the entropy source.

[0028] Alternatively, the tamper detector can be arranged in the semiconductor substrate at a different height than the detector. The distance to the surface of the semiconductor substrate is then different from the distance of the detector to the surface. Thus, the tamper detector is arranged next to the entropy source or photon source. The distance parallel to the surface can vary and can be adjusted according to the design of the quantum random number generator.

[0029] Alternatively, and equally preferably, the tamper detector can be arranged outside the semiconductor substrate. It can be a standalone element or a standalone component arranged in another semiconductor substrate or outside the semiconductor substrate associated with the quantum random number generator.

[0030] In a preferred embodiment of the invention, the device comprises a plurality of tamper detectors. The tamper detectors are preferably arranged spatially distributed around the entropy source. Particularly preferably, the arrangement is spatially evenly distributed. This can be achieved in particular when significantly more than two tamper detectors are provided, for example four, six, eight, twelve, sixteen or more. The number of tamper detectors can vary depending on the embodiment. Even with a spatially evenly distributed arrangement around the entropy source, the individual tamper detectors can be arranged at different heights, i.e., at different distances from the surface of the semiconductor substrate, if the tamper detectors are provided in the semiconductor substrate. The same applies to externally arranged tamper detectors. The detection of tampering can be improved by having a plurality of tamper detectors.

[0031] In a preferred embodiment with multiple tamper detectors in the device, it can be provided that two of the tamper detectors are different. Preferably, the tamper detectors are different in such a way that they differ in design, type, control and / or operating voltage. For example, one of the tamper detectors can be designed as an n-SPAD, the other as a p-SPAD. In this way, a wide range of light waves can be received. It is also possible to design one tamper detector as a photodiode, another as an avalanche diode and a third as a SPAD. Although the sensitivity of a photodiode is significantly lower than that of an avalanche diode or a SPAD, the photodiode, like the avalanche diode, has a higher dynamic range than a SPAD. The photodiode therefore saturates later than a SPAD.This prevents strong external interference or strong ambient light from driving the detector into saturation, rendering the tamper detector virtually blind and making it impossible to detect external interference. This is particularly prevented by using several different tamper detector types.

[0032] Preferably, the tamper detectors are divided into at least two groups of tamper detectors, each of the groups comprising detectors of the same type. However, the groups have different types. In another particular embodiment, three groups or four groups of tamper detectors are provided. For example, the groups can be controlled with different operating voltages.

[0033] Likewise, only two groups of tamper detectors are preferred, with one group having the same operating voltage as the detector of the quantum random number generator. This way, only one other operating voltage needs to be provided within the device.

[0034] In a further preferred embodiment, the device comprises a plurality of tamper detectors, some or all of which are combined or interconnected to form a photomultiplier. The interconnected tamper detectors are preferably of the same type, for example, photodiodes or avalanche diodes. For example, the interconnected tamper detectors are of the same SPAD type.

[0035] The tamper detectors can therefore be either deep SPADs or additional photodetectors or SPADs mounted in the environment that can detect extraneous light or external interference. These can be simple photodiodes or conventional n-SPADs or p-SPADs. An implementation with "low-voltage SPADs" with a lower operating voltage is also conceivable. A combination of different detector types is conceivable and preferred.

[0036] The use of multiple tamper detectors in the form of SPADs is advantageous because each SPAD has a so-called dark count rate. This means that an event is detected without external light falling on the detector. Using multiple SPADs as tamper detectors eliminates false triggering and incorrect detection of tampering. Simultaneous triggering of multiple SPADs or multiple tamper detectors is attributed to external light, i.e., stray light, external interference, or other interference.

[0037] When connecting tamper detectors to form a photomultiplier, SPADs of the same type and with the same operating voltage are preferred. Thus, in addition to an additional operating voltage, only evaluation or readout electronics are required. It is also possible to control the monitoring detectors or tamper detectors individually, for example, if they are to operate in different operating modes or in different sensitivity ranges. Combining different photodiodes or SPAD types, which typically have different sensitivities depending on the wavelength of the light or the wavelength of the penetrating radiation, is also conceivable and desirable.

[0038] In a preferred embodiment, the tamper detector is equipped with an optical window. Likewise, the semiconductor substrate (or region) associated with the tamper detector is equipped with an optical window. This prevents shadowing by metal surfaces. This increases the detector's sensitivity to external radiation.

[0039] In a preferred embodiment, the device comprises an evaluation unit by which the detector and / or tamper detector can be evaluated and the measurement results can be compared. The detection of events is understood here as a measurement result.

[0040] The evaluation unit is preferably designed to detect tampering from the measurement results or events detected by the tamper detector. The evaluation unit is preferably designed to detect tampering from the measurement results or events detected by the detector and tamper detector, preferably using a comparison criterion. The number of events detected by the detector and the tamper detector can be counted. If the difference between the two numbers of events is less than a predetermined threshold, tampering is detected.

[0041] The same applies if multiple manipulation detectors are used and evaluated. Here, manipulation is detected if several or preferably all or particularly preferably at least 90% of all manipulation detectors, more preferably at least 80%, more preferably at least 70%, more preferably at least 50% of all manipulation detectors detect an event simultaneously. "Simultaneously" in this context means within one processing cycle of the processor or the evaluation unit or an evaluation electronics.

[0042] A preferred embodiment of the device comprises a second quantum random number generator. This can be useful if several true random numbers are to be generated simultaneously and / or independently of one another.

[0043] A further preferred embodiment can provide for the detector of the second quantum random number generator to be used and employed as a manipulation detector. This second detector, i.e., the detector of the second quantum random number generator, is then the manipulation detector. In this case, the device may not comprise a further, explicit manipulation detector, but only the detector of the second generator. Alternatively, the detector of the second quantum random number generator can be used as an additional, i.e., second or further, manipulation detector in order to increase the independence of the manipulation detectors and improve the detection of manipulation.

[0044] The detector of the second quantum random number generator is used as a tamper detector and is deployed when the entropy source of the second quantum random number generator is switched off or out of operation, for example, for power-saving reasons, such as when high data rates are not required. It is then not used as an entropy source. In a preferred embodiment, the second quantum random number generator can be designed without shadowing, i.e., without any shadowing or external shielding.

[0045] A preferred embodiment of the device provides that the tamper detector detects at least the type of radiation emitted by the entropy source. The tamper detector is therefore sensitive to the radiation generated by the entropy source. Further preferably, the tamper detector is sensitive to any type of radiation to which the detector of the quantum random number generator is also sensitive, i.e., to the radiation that the detector can detect. However, the tamper detector particularly preferably has a wider sensitivity range than the detector. The tamper detector can therefore detect radiation in a wider frequency range or a wider wavelength range. This ensures that a wide spectrum of interference radiation is detected. The tamper detector is thus an extraneous light detector or extraneous radiation detector.

[0046] If one or more of the tamper detectors are triggered (simultaneously or quasi-simultaneously, i.e., in the same processing cycle), this can trigger actions in the quantum random number generator. In this case, an attack or interference is suspected, or tampering is detected. For example, a message can be sent to a controller or the generation of random numbers can be stopped.

[0047] Overall, the device according to the invention has the advantage that, thanks to the monolithic structure of the quantum random number generator, attacks caused by external radiation or extraneous light can be detected locally, allowing timely measures to be taken, as described above. This is important to guarantee the security of the application in which the quantum random number generator is used and its random numbers are processed.

[0048] In a particular embodiment of the integrated circuit with a semiconductor substrate, at least one second quantum random number generator is integrated into the integrated circuit (IC). Preferably, at least one of the quantum random number generators is shaded or shielded to be resistant to external interference. Particularly preferably, when using multiple quantum random number generators, at least the entropy source of one of the quantum random number generators is switched off, and its detector is used as a tamper detector. With more than two quantum random number generators, all but one of the other quantum random number generators can be switched off, so that the detectors of these random number generators are used as additional tamper detectors.

[0049] A network with multiple quantum random number generators (QRNGs) and at least one tamper detector is a possible application for a QRNG with increased security against external tampering, in particular against radiated and / or optical tampering. This also includes tampering with photons or single photons. The tamper detector is suitable and configured to detect radiation detectable by the detector. It is shielded from the quantum random number generators such that detected radiation is free from radiation from one of the entropy sources of the QRNG in the network. The network can comprise multiple nodes, each node comprising a control unit and / or a QRNG. The tamper detector is preferably included in at least one of the nodes.

[0050] The quantum random number generator, in particular one suitable for a device as described above, has a semiconductor substrate comprising an entropy source and a detector. The entropy source is a photon source. The detector is configured to detect radiation emitted by the entropy source. The photon source and the detector are arranged in the semiconductor substrate such that the photon source is arranged between the detector and a surface of the semiconductor substrate. The entropy source and detector are arranged vertically with respect to the surface normal of the substrate surface.

[0051] The entropy source of the QRNG is preferably a planar Zener diode that radiates radiation over a large area into the planar detector arranged below the entropy source. The area of ​​the entropy source preferably corresponds to the area of ​​the detector; particularly preferably, the surface areas are the same. The planar elements have a planar extent. The planar extent forms the active region of the elements, i.e. the area from which radiation can be emitted or detected. Radiation can therefore be emitted or detected from any point of the planar extent. A planar Zener diode and / or detector or SPAD are not point sources or point receivers. Their area preferably has longitudinal and transverse sides of equal length or of unequal length and is delimited by these. The areas can be the same size or have the same dimension.

[0052] In a preferred embodiment, the entropy source of the QRNG is a planar Zener diode. One or more SPADs are provided in the semiconductor substrate, preferably one or more SPADs are arranged below the entropy source. Particularly preferably, one SPAD is a detector, and one or more SPADs form one or more tamper detectors.

[0053] The detector is preferably an avalanche diode, preferably a SPAD. A tamper detector is preferably configured in the semiconductor substrate such that it is arranged in a radiation-free region without radiation from the entropy source, i.e., in a shadow region.

[0054] In a preferred embodiment, the entropy source of the QRNG is arranged between a metal layer, preferably forming a metal cover, and the detector. The metal layer directs the radiation emitted by the entropy source toward the detector and / or forms a shield against radiation from the environment. This protects the QRNG against external manipulation. This protection can be further improved by the device described above.

[0055] Preferably, the entropy source and the detector are formed monolithically in the semiconductor substrate, and the entropy source is preferably arranged above the detector. Particularly preferably, a metal layer arranged above the entropy source is also integrated into the QRNG. Such a QRNG can be formed or manufactured as follows, for example, in a process using CMOS technology or BCD technology (bipolar CMOS-DMOS technology), preferably also with a tamper detector:

[0056] Forming an entropy source in the form of a photon source in a semiconductor substrate; forming a detector in the form of an avalanche diode or a SPAD in the semiconductor substrate below the entropy source (as viewed from a surface of the semiconductor substrate). The entropy source and the detector are preferably formed monolithically in the semiconductor substrate. Additionally, a metal layer can optionally be arranged or formed above the entropy source to achieve shielding against environmental radiation. It can be integrated into the semiconductor substrate.

[0057] The invention is described and explained in more detail below using selected embodiments in conjunction with the accompanying drawings. They show:

[0058] Figure 1 shows a device according to the invention for detecting manipulation of a quantum random number generator;

[0059] Figure 2 shows a further alternative embodiment of the device;

[0060] Figure 3 shows a further variant of a preferred embodiment of the device;

[0061] Figure 4 shows a variant of a quantum random number generator with multiple manipulation detectors;

[0062] Figure 5 shows an alternative embodiment of the device with a quantum random number generator and several manipulation detectors of different types;

[0063] Figure 6 shows a network with several devices according to the invention; Figure 7 shows a schematic sequence of a method according to the invention and

[0064] Figure 8 shows an application example of a device according to the invention.

[0065] Figures 1 to 6 show several embodiments of a device 10 according to the invention for detecting manipulation of a random number generator.

[0066] Figure 1 shows the device 10 according to the invention with a quantum random number generator 20 and a tamper detector 30. The quantum random number generator 20 has a semiconductor substrate 22 comprising an entropy source 24 and a detector 28. The entropy source 24 is a photon source 26. The detector 28 is designed and configured to detect radiation emitted by the entropy source 24. The operation of such a quantum random number generator 20 is known from the prior art.

[0067] The tamper detector 30 is arranged in the device 10 such that it is located in a shadow region 32. The shadow region 32 refers to the entropy source 24 and is the area into which no radiation from the entropy source 24 or the photon source 26 reaches, but which is shaded from this radiation.

[0068] The device 10 further comprises an evaluation unit 40 for processing measurement results and detections from both the detector 28 and the tamper detector 30. The processing includes, among other things, the ability to detect the intrusion of interfering radiation or extraneous light, and to detect influences or other external tampering, preferably optical tampering. The evaluation unit 40 may comprise a processor. It may also be integrated into the quantum random number generator 20. An output interface 50 is configured and serves to output a tamper signal generated by the evaluation unit 40 for detecting tampering, for example, to a controller or to other components in the environment or to connected parts, components, devices, or systems.

[0069] Figure 1 further shows an optional shield 34, which is created, for example, by a metal plate or metal layer 36. Thus, it is possible to define the shadow area 32 by means of the shield 34, in which the tamper detector 30 is arranged.

[0070] Figure 2 shows an alternative embodiment of the device 10. Here, the quantum random number generator 20 with its semiconductor substrate 22 also includes the tamper detector 30. In other words, the tamper detector 30 is integrated into the semiconductor substrate 22. In this case, too, an optional shield 34 can be implemented, for example, by a metal layer 36.

[0071] The output interface 50 is located outside the quantum random number generator 20. The evaluation unit 40 can be integrated into the generator or located outside.

[0072] In an alternative embodiment, the tamper detector 30 is included in the semiconductor substrate 22, which also includes the semiconductor substrate of the quantum random number generator 20. The tamper detector 30 is preferably arranged on the same semiconductor substrate 22 as the quantum random number generator 20. However, it can also be arranged outside the quantum random number generator 20.

[0073] Figure 3 shows a further alternative embodiment of the device 10 with two quantum random number generators 20 sharing a tamper detector 30. The quantum random number generators 20 and the tamper detector 30 can all be arranged on the same semiconductor substrate 22. An optional shield 34 can also be provided to allow a shadow region 32 in which the tamper detector 30 is arranged. This further ensures that radiation from the photon sources 26 of the quantum random number generators 20 does not reach the tamper detector 30.

[0074] In this embodiment, it is possible for the photon source 26 of one of the quantum random number generators 20 to be deactivated or switched off. The detector 28 of this generator can then be operated as an additional tamper detector 30.

[0075] The manipulation detector 30 is preferably designed with a so-called optical window, preventing shadowing from metal surfaces. This makes the manipulation detector 30 more sensitive to external radiation, i.e., radiation from outside the device, which could be used to influence or manipulate the quantum random number generator 20.

[0076] Figure 4 shows a further embodiment of the device 10 with a quantum random number generator 20 and a plurality of manipulation detectors 30 arranged in the vicinity of the quantum random number generator 20. The manipulation detectors 30 surround the quantum random number generator 20 in this embodiment. Eight manipulation detectors 30 are provided by way of example. It is understood that a different number of manipulation detectors may also be used, for example, two, four, six, eight, nine, ten, twelve, fourteen, sixteen, eighteen, or twenty-four.

[0077] The multiple tamper detectors 30 can be SPADs, for example. In a simple variant, as shown here, the tamper detectors 30 can all be SPADs of the same SPAD type. They are preferably operated with only one operating voltage. Consequently, only one additional operating voltage needs to be provided for the device. These voltage sources are not shown in any of the figures shown. The tamper detectors 30 of the same type shown here can be combined or connected to form a photomultiplier. It is possible to control the tamper detectors 30 individually, for example, by setting them to different operating modes or having them operate with different sensitivity ranges.

[0078] In general, tamper detectors 30 designed as SPADs can be operated with different voltages. Typically, three different operating modes can be set: photodiode mode, avalanche photodiode mode (avalanche mode), and SPAD mode. Generally, the sensitivity of the tamper detector 30 increases with increasing voltage. This means that it can detect smaller amounts of light, down to the detection of individual photons or individual light particles, when the tamper detector 30 is operated in SPAD mode. In SPAD mode, the voltage is highest. It is generally above the breakdown voltage. In avalanche mode, the voltage is below the breakdown voltage; the sensitivity here can be classified as medium. In photodiode mode, the tamper detector is operated with a low operating voltage. The sensitivity is lowest in this mode.However, the dynamic range is highest, and decreases with increasing voltage. The higher the voltage applied to the tamper detector 30, the lower the dynamic range, i.e., the optical power that leads to detector saturation decreases.

[0079] Figure 5 shows an alternative embodiment of the device according to Figure 4. In this example, tamper detectors 30 of two different types are used, which surround, i.e., are arranged around, the one quantum random number generator 20. For example, one type of tamper detector 30 can consist of n-SPAD detectors 38, and the second type of tamper detector 30 can consist of p-SPAD detectors 39.

[0080] Figure 6 shows a network 60 according to the invention with a plurality of quantum random number generators 20 and control units 62, wherein the control units 62 are designed and used for communication between the individual quantum random number generators 20 in the network 60. Only the quantum random number generators 20 are shown in Figure 6; they can of course each be integrated into a device 10 and thus each also include a manipulation detector 30. It is also possible for a single manipulation detector 30 to be provided in each of the network nodes 64 formed by the quantum random number generator 20 and the control unit 62. Alternatively, one or some of the nodes 64 can be designed as a manipulation detector 30 and supply the other nodes 64. The control units 62 also enable communication between the individual nodes 64.

[0081] Figure 7 shows the basic sequence of the inventive method for detecting manipulation of a quantum random number generator by external influence. Detection is performed by means of a manipulation detector 30. The quantum random number generator 20 has a semiconductor substrate 22 comprising an entropy source 24, which is a photon source 26, and a detector 28 configured to detect the radiation emitted by the entropy source 24.

[0082] In a first step S 10, the tamper detector 30 is read. In a further step S 12, external tampering, in particular external optical tampering or interference, is detected. Detection in step S 12 is based on a predetermined criterion. This can be a tamper detection criterion or a comparison criterion.

[0083] In a further step S14, a manipulation signal is generated and further processed. Further processing can, for example, be forwarded via an output interface 50 to transmit the manipulation signal to a controller or to other components of a higher-level unit, device, or system, so that further processing can take place there. Alternatively or additionally, the manipulation signal can be processed directly in the device according to the invention and, for example, result in the deactivation of the quantum random number generator 20.

[0084] In a preferred embodiment of the method, step S 12 comprises further optional steps S 20 to S 28 to detect external manipulation based on a criterion.

[0085] In an optional step S20, photon radiation is emitted by the entropy source 24 or the photon source 26. A step S22 of receiving radiation by the detector 28 follows. In a step S24, the detector 28 is read out. A step S26 comprises comparing the measured values ​​of the detector 28 with the measured values ​​of the tamper detector 30. Measured values ​​of the detectors are understood here to mean that an event occurring in the detector is detected. How this is done is known in the prior art, for example, from DE 102022152572 A1, WO 2024 / 074170 A1, or DE 10223126268 A1.

[0086] In a further step S 28, a decision is made based on the comparison of the measured values ​​and predefined comparison criteria as to whether external manipulation is expected or whether external interference, for example, through radiation, particularly optical radiation, has occurred. This decision is further processed as a criterion in step S 12, so that if the decision is positive, i.e., if it is assumed that interference has occurred, a manipulation signal can be generated.

[0087] Figure 8 shows a vehicle 70 with a device 10 according to the invention, wherein the device 10 can, for example, comprise one of the variants described above according to Figures 1 to 5 or a network 60 according to Figure 6. The vehicle 70 and the device 10 thus form a system comprising these two components. For example, in the system, the device 10 can be designed as an integrated circuit, so that the integrated circuit is installed in the vehicle 70. Preferably, the device 10 or the quantum random number generator 20 comprised in the device 10 is used to encrypt data within the vehicle 70. Alternatively, and likewise preferably, the device 10 is used to encrypt communication within the vehicle 70 or with a component outside the vehicle 70.For example, the random numbers generated by the quantum random number generator 20 of the device 10 can be used for communication between the vehicle 70 and a vehicle key, for example to encrypt the communication so that it can take place without interference.

[0088] Of course, it is also conceivable that a network 60 is included in the vehicle 70, so that the vehicle 70 and the network 60 form a system with a plurality of devices 10 or a plurality of quantum random number generators 20.

[0089] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to those skilled in the art upon use of the present invention and upon careful analysis of the drawings, the disclosure, and the following claims.

[0090] In the claims, the words "comprising" and "having" do not exclude the presence of further elements or steps. The undefined article "a" or "an" does not exclude the presence of a plurality. A single element or unit can perform the functions of several of the components mentioned in the claims. An element, unit, device, and system can be partially or completely implemented in hardware and / or software. The mere mention of some measures in several different dependent claims should not be understood to mean that a combination of these measures cannot also be used advantageously. Reference symbols:

[0091] 10 Device

[0092] 20 Quantum Random Number Generator

[0093] 22 Semiconductor substrate

[0094] 24 Entropy source

[0095] 26 photon source

[0096] 28 detector

[0097] 30 Tamper detector

[0098] 32 shadow area

[0099] 34 Shielding

[0100] 36 metal layer

[0101] 38 n-SPAD

[0102] 39 p-SPAD

[0103] 40 Evaluation unit

[0104] 50 Output interface

[0105] 60 Network

[0106] 62 control unit

[0107] 64 knots

[0108] 70 vehicles

Claims

Patent claims 1. A device for detecting tampering with a quantum random number generator, comprising a quantum random number generator (20) with a semiconductor substrate (22) that includes an entropy source (24), which is a photon source (26), and a detector (28) configured to detect radiation emitted by the entropy source (24), and a tamper detector (30) configured to detect radiation detectable by the detector (28); wherein the tamper detector (30) is arranged in the vicinity of the detector (28); the tamper detector (30) is shielded from the entropy source (24) such that only radiation from outside the entropy source (24) is detectable.

2. Device according to claim 1, characterized in that the shielding of the manipulation detector (30) from the entropy source (24) is carried out by an arrangement of the manipulation detector (30) relative to the entropy source (24) in such a way that no radiation from the entropy source (24) reaches the manipulation detector (30), or by a shielding element which is arranged between the manipulation detector (30) and the entropy source (24) in such a way that no radiation from the entropy source (24) reaches the manipulation detector (30).

3. Device according to one of the preceding claims, characterized in that the manipulation detector (30) comprises a photodiode, a Avalanche diode, a single-photon avalanche diode (SPAD), preferably a DeepSPAD, an n-SPAD (38) or a p-SPAD (39).

4. Device according to one of the preceding claims, characterized in that the manipulation detector (30) is integrated in the semiconductor substrate (22).

5. Device according to one of the preceding claims, characterized in that the device (10) comprises a plurality of manipulation detectors (30) which are preferably arranged spatially distributed around the entropy source (24), particularly preferably spatially uniformly distributed.

6. Device according to claim 5, characterized in that at least two of the manipulation detectors (30) are different, preferably so different that they differ in design, type, control and / or operating voltage.

7. Device according to one of the preceding claims 5 or 6, characterized in that several manipulation detectors (30) are connected or interconnected to form a photomultiplier and are preferably of the same type, preferably a SPAD of the same SPAD type.

8. Device according to one of the preceding claims, characterized in that the device (10) comprises an evaluation unit (40) by means of which the detector (28) and the manipulation detector (30) are evaluated and the measurement results are compared, wherein the evaluation unit (40) is designed to detect manipulation from the measurement results of the detector (28) and the manipulation detector (30), preferably based on a comparison criterion.

9. Device according to one of the preceding claims, characterized in that the device (10) comprises a second quantum Random number generator (20) and preferably the detector (28) of the second quantum random number generator (20) is the manipulation detector (30) when the entropy source (24) of the second quantum random number generator (20) is switched off or out of operation.

10. Device according to one of the preceding claims, characterized in that the manipulation detector (30) detects at least the type of radiation emitted by the entropy source (24), preferably any type of radiation to which the detector (28) is sensitive, particularly preferably the manipulation detector (30) has a larger sensitivity range than the detector (28).

11. Device according to one of the preceding claims, characterized in that the entropy source (24) of the quantum random number generator (20) is designed as a planar Zener diode, preferably as a silicon LED, which is arranged above the detector (28), preferably a planar SPAD.

12. Quantum random number generator, particularly suitable for a device according to one of the preceding claims, with a semiconductor substrate (22) comprising an entropy source (24), which is a photon source (26), and a detector (28) which is designed to detect radiation emitted by the entropy source (24), wherein the photon source (26) and the detector (28) are arranged in the semiconductor substrate (22) such that the photon source (26) is arranged between the detector (28) and a surface of the semiconductor substrate (22).

13. Quantum random number generator according to the preceding claim, characterized in that the entropy source (24) is a planar Zener diode which radiates radiation over a large area into the planar detector which is arranged below the entropy source (24), wherein preferably the area of ​​the entropy source (24) is identical to the area of ​​the detector (28), particularly preferably the areas are equal.

14. Quantum random number generator according to one of claims 12 to 13, characterized in that the entropy source (24) is a planar Zener diode and one or more SPADs are provided in the semiconductor substrate, wherein preferably one or more SPADs are arranged below the entropy source and particularly preferably one SPAD is a detector (28) and one or more SPADs form a manipulation detector (30).

15. Quantum random number generator according to one of claims 12 to 14, characterized in that the detector (28) is an avalanche diode, preferably a SPAD, and a manipulation detector (30) is arranged in the semiconductor substrate (22) such that it is in a radiation-free area without radiation from the entropy source (24).

16. Quantum random number generator according to one of claims 12 to 15, characterized in that the entropy source (24) is arranged between a metal layer, which preferably forms a metal cover, and the detector (28), wherein the metal layer directs the radiation emitted by the entropy source (24) towards the detector (28) and / or forms a shield against radiation from the environment.

17. Quantum random number generator according to one of claims 12 to 16, characterized in that the entropy source (24) and the detector (28) are formed monolithically in the semiconductor substrate (22), preferably the entropy source (24) above the detector (28), particularly preferably also a metal layer which is arranged above the entropy source (24).

18. Vehicle (70) with a device (10) according to one of the preceding claims.

19. Integrated circuit with a semiconductor substrate (22) in which a quantum random number generator (20) with an entropy source (24) designed as a photon source (26) and a detector (28) for detecting radiation from the photon source (26) is arranged, characterized in that the integrated circuit comprises a tamper detector (30) which is designed to detect radiation to which the detector (28) is sensitive and which is arranged in the vicinity of the detector (28) and which is shielded from the entropy source (24) in such a way that no radiation from the entropy source (24) is detected.

20. Integrated circuit according to the preceding claim, characterized in that the integrated circuit comprises at least one second quantum random number generator (20), wherein preferably at least one of the quantum random number generators (20) is shaded or shielded in order to be resistant to interference radiation from outside, wherein preferably the entropy source (24) of at least one quantum random number generator (20) is switched off and its detector (28) is the tamper detector (30).

21. Integrated circuit according to the preceding claim, characterized in that the integrated circuit is installed in a vehicle (70) and can preferably be used for encrypting data and / or communication within or with components outside the vehicle (70).

22. A network (60) comprising a plurality of quantum random number generators (20) and at least one tamper detector (30), wherein each quantum random number generator (20) has a semiconductor substrate (22) comprising an entropy source (24) which is a photon source (26) and a detector (28) configured to detect radiation emitted by the entropy source (24), and wherein the manipulation detector (30) is designed to detect radiation that is detectable by the detector (28) and is shielded from entropy sources (24) of the quantum random number generators (20).

23. A method for detecting manipulation of a quantum random number generator (20) by external influence by means of a manipulation detector (30), wherein the quantum random number generator (20) has a semiconductor substrate (22) comprising an entropy source (24), which is a photon source (26), and a detector (28) configured to detect radiation emitted by the entropy source (24), comprising the following steps: Reading the tamper detector (30); Recognizing, based on a given criterion, that external manipulation is expected; Generating and further processing a manipulation signal.

24. Method according to the preceding claim, characterized in that the step of detecting, on the basis of a predetermined criterion, that external manipulation is expected comprises the further steps of: optionally emitting photon radiation by means of the entropy source (24); Receiving radiation by means of the detector (28); Reading the detector; Comparing the measured values ​​of the detector (28) with the measured values ​​of the tamper detector (30); Based on the comparison and given comparison criteria, decide that external manipulation is expected.

25. A method for producing a quantum random number generator (20), preferably a quantum random number generator (20) according to one of claims 12 to 16, comprising the following steps: Forming an entropy source in the form of a photon source in a semiconductor substrate; Forming a detector in the form of an avalanche diode or a SPAD in the semiconductor substrate below the entropy source as viewed from a surface of the semiconductor substrate; wherein the entropy source and the detector are formed monolithically in the semiconductor substrate.

26. Method according to the preceding claim, comprising the further step: Forming a manipulation detector in the semiconductor substrate such that the manipulation detector is arranged in a radiation-free region without radiation from the entropy source (24).

27. Method according to claim 25 or 26, characterized in that the entropy source and the detector are manufactured using CMOS technology or BCD technology, preferably also the manipulation detector.

28. A method according to any one of claims 25 to 27, comprising the further step: Formation of a metal layer above the entropy source to achieve shielding against radiation from the environment.

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