Hardware tampering detection coating based on unclonable physical characteristics of carrier plate

Abstract

The invention relates to a hardware tampering detection coating based on unclonable physical characteristics of a carrier board, the hardware tampering detection coating is arranged on the on-board component side of a printed circuit board, the hardware tampering detection coating comprises a substrate and conductor particles, the substrate comprises an insulating material, and the conductor particles are arranged on the substrate. The conductor particles are randomly distributed in the substrate. By arranging the hardware tampering detection coating on the onboard element side of the printed circuit board, if the onboard element of the printed circuit board is replaced or removed, the random distribution state of the conductor particles generates irreversible change, so that the electrical characteristics of the hardware tampering detection coating generate irreversible change; and the unrecoverable change of the impedance characteristic of the printed circuit board is also caused. By detecting the impedance of the printed circuit board, malicious modification behaviors such as removal or replacement of onboard elements of the printed circuit board can be detected, and the accuracy of anomaly detection of the printed circuit board is effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of printed circuit board anomaly detection, and in particular to a hardware tamper detection coating based on the unclonable physical properties of a carrier board. Background Art

[0002] With the widespread use of printed circuit boards (PCBs) in modern electronic devices and embedded systems, their integrity has become critical. However, the global supply chain and increasingly complex PCB design make it possible for the PCB to be attacked maliciously at all stages of its life cycle. Specifically, malicious attacks on PCBs can include removing or replacing onboard components on the PCB. Since the PCB is modified, its PDN (power distribution network) characteristics will inevitably change. Based on this, traditional technology can determine whether the PCB is abnormal due to malicious attacks by detecting the impedance characteristics of the PCB.

[0003] However, although the impedance changes significantly when the onboard components on the printed circuit board are removed, the impedance characteristics of the printed circuit board PDN change less when the onboard components on the printed circuit board are replaced, making it difficult for traditional technologies to detect. Therefore, the accuracy of the abnormal detection results of the traditional technology for the printed circuit board is low. Summary of the invention

[0004] Based on this, it is necessary to provide a hardware tampering detection coating based on the unclonable physical properties of the substrate that can improve the accuracy of anomaly detection in order to address the above technical problems.

[0005] In a first aspect, the present application provides a hardware tamper detection coating for a printed circuit board, wherein the hardware tamper detection coating is disposed on the onboard component side of the printed circuit board, and the hardware tamper detection coating includes a substrate and conductor particles, wherein the substrate includes an insulating material, and the conductor particles are randomly distributed in the substrate.

[0006] In one embodiment, the conductive particles are uniformly distributed in the substrate.

[0007] In one embodiment, the conductive particles are metal particles.

[0008] In one embodiment, the diameter of the conductive particles is 500 nanometers to 0.5 millimeters.

[0009] In one embodiment, the insulating material includes at least one of epoxy resin, silicone resin and acrylic resin.

[0010] In one of the embodiments, one side of the hardware tamper detection coating is in contact with the onboard component side of the printed circuit board, and an electromagnetic shielding layer is disposed on the other side of the hardware tamper detection coating.

[0011] In a second aspect, the present application further provides a method for manufacturing a hardware tamper detection coating based on the non-clonable physical property of a carrier board, the method being used to manufacture the hardware tamper detection coating described in any one of the first aspects above, the method comprising:

[0012] Mixing the insulating materials based on a preset ratio to obtain the substrate;

[0013] randomly and uniformly placing the conductive particles in the substrate to obtain the hardware tamper detection coating;

[0014] uniformly applying the hardware tamper detection coating to the onboard component side of the printed circuit board;

[0015] After the coated hardware tampering detection coating is left to stand at a preset temperature for a preset period of time, a detection electrode is arranged on the surface of the hardware tampering detection coating, and the detection electrode is used to detect the impedance of the hardware tampering detection coating.

[0016] In one embodiment, before randomly and uniformly placing the conductive particles in the substrate, the method further comprises:

[0017] In one embodiment, the step of randomly and uniformly placing the conductive particles in the substrate comprises:

[0018] Based on at least one stirring method selected from manual stirring, mechanical stirring, and ultrasonic stirring, the substrate into which the conductive particles are placed is continuously stirred for a preset time period.

[0019] In one embodiment, before the hardware tamper detection coating is evenly applied to the onboard component side of the printed circuit board, the method further includes:

[0020] The hardware tamper detection coating is placed in a vacuum degassing machine for degassing treatment.

[0021] The above-mentioned hardware tampering detection coating based on the non-clonable physical characteristics of the carrier board is achieved by setting the hardware tampering detection coating on the onboard component side of the printed circuit board, wherein the hardware tampering detection coating includes a substrate and conductor particles. If the onboard components of the printed circuit board are replaced or removed, the random distribution state of the conductor particles will undergo irreversible changes, thereby causing irreversible changes in the electrical characteristics of the hardware tampering detection coating, and will also cause irreversible changes in the impedance characteristics of the printed circuit board. By detecting the impedance of the printed circuit board, malicious modifications such as removal or replacement of the onboard components of the printed circuit board can be detected, effectively improving the accuracy of abnormal detection of the printed circuit board.

[0022] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0024] Figure 1 A schematic diagram of a hardware tamper detection coating based on the unclonable physical property of a carrier board in one embodiment;

[0025] Figure 2 A schematic diagram of a printed circuit board and a hardware tamper detection coating in one embodiment;

[0026] Figure 3 is a schematic diagram of a printed circuit board and a hardware tamper detection coating in a specific embodiment;

[0027] Figure 4 It is a flowchart of a method for manufacturing a hardware tamper detection coating based on the non-clonable physical property of a carrier board in one embodiment;

[0028] Figure 5 The figure is a schematic flow chart of a method for pretreating conductor particles in one embodiment.

[0029] Figure numerals: 20, hardware tamper detection coating based on the unclonable physical properties of the carrier board; 21, printed circuit board; 211, onboard components; 212, dielectric layer; 213, prepreg layer; 214, solder; 215, pins; 216, conductor material; 30, electromagnetic shielding layer. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0031] The terms "module", "unit", etc. used below are a combination of software and / or hardware that can implement a predetermined function. Although the devices described in the following embodiments are preferably implemented in hardware, the implementation of software, or a combination of software and hardware is also possible and conceivable.

[0032] In the present application embodiment, Figure 1As shown, a hardware tamper detection coating 20 based on the non-clonable physical property of the carrier is provided, wherein the hardware tamper detection coating 20 is arranged on the side of the onboard component 211 of the printed circuit board 21, and the hardware tamper detection coating 20 includes a substrate and conductive particles, wherein the substrate includes an insulating material, and the conductive particles are randomly distributed in the substrate.

[0033] In the embodiment of the present application, the printed circuit board 21 is a support body of electronic components made by electronic printing technology, and is used to provide a circuit connection carrier for the electronic components. On-board components are installed on one side of the printed circuit board 21, and the pins of the on-board components 211 extend to the other side of the printed circuit board 21 and are soldered to the other side of the printed circuit board 21. The hardware tamper detection coating 20 provided in the present application is arranged on the on-board component 211 side of the printed circuit board 21.

[0034] The hardware tampering detection coating 20 includes two materials with large differences in dielectric constants, usually an insulator material and a conductor material. The hardware tampering detection coating 20 can be a network-like coating. In some embodiments, the hardware tampering detection coating 20 includes a substrate and conductor particles. Among them, the substrate includes an insulating material, and the conductor particles are randomly distributed in the substrate. In the embodiment of the present application, the height of the hardware tampering detection coating can be set to be less than the height of the on-board components. By randomly mixing conductor particles into the substrate, on the one hand, the electrical characteristics of the hardware tampering detection coating can be guaranteed, and when the on-board components of the printed circuit board are removed or replaced, the impedance change can be accurately and sensitively detected; on the other hand, the hardware tampering detection coating can also improve the mechanical strength of the printed circuit board, and effectively improve the working stability of the printed circuit board.

[0035] In some embodiments, the conductive particles are evenly distributed in the substrate. Evenly distributed conductive particles can make the impedance characteristics of the printed circuit board 21 change more significantly when any onboard component 211 on the printed circuit board 21 is removed or replaced, further improving the sensitivity and accuracy of abnormal detection of the printed circuit board 21.

[0036] In some embodiments, the conductor particles are metal particles. Specifically, the conductor particles can be silver particles, copper particles, aluminum particles, titanium particles, etc. The diameter of the conductor particles is 500 nanometers to 0.5 millimeters. This application does not limit the specific material of the conductor particles. Metal particles have good electrical conductivity and mechanical strength. While improving the accuracy of abnormal detection of the printed circuit board 21, they can also enhance the physical strength of the hardware tamper detection coating 20, thereby improving the durability of the printed circuit board 21.

[0037] In some embodiments, the insulating material includes at least one of epoxy resin, silicone resin and acrylic resin. It is understandable that the insulating material can be any one of epoxy resin, silicone resin and acrylic resin, or a mixture of any two or three. Specifically, if the insulating material is epoxy resin, based on the conventional use of epoxy resin, component A and component B are mixed evenly in a specified ratio (such as 1:1) as the substrate of the hardware tamper detection coating 20.

[0038] In some embodiments, one side of the hardware tamper detection coating 20 is attached to the onboard component 211 side of the printed circuit board 21 , and the other side of the hardware tamper detection coating 20 is provided with an electromagnetic shielding layer 30 .

[0039] In the embodiment of the present application, in order to enhance the electromagnetic shielding performance of the printed circuit board 21, an electromagnetic shielding layer 30 may be further provided on the hardware tamper detection coating 20. Specifically, one side of the abnormality detection layer is bonded to the onboard component 211 side of the printed circuit board 21, and the other side of the abnormality detection layer may be bonded to the electromagnetic shielding layer 30. In some specific embodiments, the electromagnetic shielding layer 30 may include a dielectric and a conductive layer.

[0040] In some specific embodiments, the schematic diagram of the printed circuit board 21 and the coating is as follows Figure 2 As shown. The onboard component 211 side of the printed circuit board 21 is laminated to one side of the dielectric layer 212, the other side of the dielectric layer 212 is laminated to one side of the hardware tamper detection coating 20, and the other side of the hardware tamper detection coating 20 is laminated to the electromagnetic shielding layer 30. The dielectric layer 212 is used to electrically insulate the printed circuit board 21, prevent electrical interference between different signal layers, and ensure the integrity of the signal transmitted by the printed circuit board 21.

[0041] In some specific embodiments, the schematic diagram of the printed circuit board 21 and the coating is as follows Figure 3 As shown. A board component 211 is mounted on one side of the printed circuit board 21, and the pin 215 of the board component 211 extends to the other side of the printed circuit board 21 and is soldered to the other side of the printed circuit board 21 through solder 214. The board component 211 side of the printed circuit board 21 is covered with a hardware tamper detection coating 20. The printed circuit board 21 is also provided with a dielectric layer 212 and a prepreg layer 213. It should be noted that after the dielectric layer 212, the prepreg layer 213 and any coating in the abnormality detection layer are set, they can be regarded as part of the printed circuit board 21, or as a separate coating. Figure 3 To illustrate the structure of each coating layer, each coating layer is considered as a separate coating layer.

[0042] exist Figure 3In the printed circuit board 21 and coating shown, the on-board components 211 include components mounted on the printed circuit board 21 for performing specific functions, such as signal processing, filtering, etc. The on-board components 211 may include resistors, capacitors, etc. The dielectric layer 212 is used to electrically insulate the printed circuit board 21, prevent electrical interference between different signal layers, and ensure the integrity of the signal transmitted by the printed circuit board 21. The prepreg layer 213 includes a material used to manufacture the printed circuit board 21, which is generally used to provide mechanical support and electrical insulation. Solder 214 is used to connect the on-board components 211 and the metal part of the printed circuit board 21, ensure that the pins 215 are fixed to the printed circuit board 21, and provide electrical connection. The pins 215 are used to connect the on-board components 211 between layers through the circuit board to ensure the conduction between the on-board components 211 and the circuits of different layers. The conductor material 216 is used to provide a conductive path for electrical signals.

[0043] In an embodiment of the present application, a printed circuit board is further provided, and a hardware tamper detection coating as described in any of the above embodiments is disposed on the onboard component side of the printed circuit board.

[0044] In the embodiment of the present application, the printed circuit board described in the embodiment of the present application may be a printed circuit board based on a PDN (Power distribution network), so whether the printed circuit board is abnormal can be determined based on the PDN impedance test. PDN (Power Delivery Network) is a power distribution network, which refers to a network structure used to distribute power to various components in an electronic system. A typical PDN includes a voltage regulation module, a power rail, a power plane, a decoupling capacitor, and a power network inside the chip.

[0045] The voltage regulator module (VRM) is an important part of the PDN, which is used to convert the main power supply voltage (such as 12V) into a stable low voltage (such as 3.3V, 1.8V, etc.) required by chips or other components. The voltage regulator module usually forms a tree structure to distribute the power supply to multiple different voltage domains.

[0046] Power traces are conductors on a printed circuit board that are used to transmit the voltage output by the voltage regulator module to the pins of each chip.

[0047] Power planes are large areas of copper foil on a printed circuit board that are used to provide a low impedance path to distribute power to the various components on the printed circuit board. These planes are usually located on the internal layers of the printed circuit board to reduce electromagnetic interference (EMI).

[0048] Decoupling capacitors are set between the power rail and the ground to smooth voltage fluctuations and reduce power noise and electromagnetic interference. Decoupling capacitors are essential for maintaining a stable operating voltage of the chip.

[0049] The on-chip power grid is a power distribution network inside the chip that is used to distribute power to various areas within the chip.

[0050] In some embodiments, the PDN of the printed circuit board is composed of multiple voltage domains, each voltage domain corresponds to a set of onboard components connected to the domain and the printed circuit board area where the domain is located. Based on this, the impedance detection method of the PDN of the printed circuit board can be to select the number of test ports, and the position of the test port is determined based on the detection target. After determining the position of the test port, the printed circuit board is placed on the test bench and measured using a position controller, a vector network analyzer (VNA) and multiple probes. The VNA uses a standard two-port shunt-through method for small impedance measurements, followed by a standard two-port calibration to obtain high-precision measured impedance values.

[0051] In the embodiment of the present application, the hardware tamper detection coating formed by the substrate mixed with conductor particles has a high sensitivity. If the onboard components are removed or replaced, the physical integrity of the hardware tamper detection coating will also be destroyed, which will directly affect the impedance characteristics of the printed circuit board. And because the distribution state of the conductor particles has changed, the hardware tamper detection coating can further amplify the impedance change. Each onboard component (such as resistors, capacitors, integrated circuits, etc.) on the printed circuit board has its own specific impedance characteristics. Even if the components of the same specifications are replaced, their internal materials or welding methods may cause slight impedance differences. After the impedance change is amplified, whether the printed circuit board has a PDN structure or not, it can be accurately determined by impedance detection whether the printed circuit board is abnormal. For example, in addition to PDN, it is also possible to accurately determine whether the printed circuit board is abnormal by impedance detection through a grid-shaped metal fine track arranged on the surface of the printed circuit board. The embodiment of the present application effectively improves the accuracy and sensitivity of printed circuit board abnormality detection. In addition, the optical observation method can also be used as an auxiliary detection method to identify physical damage to the coating. In order to avoid short circuit problems, an additional layer of substrate can be covered on the outside of the hardware tamper detection coating to provide additional electrical isolation and protection.

[0052] The present application also provides a method for manufacturing a hardware tamper detection coating based on the non-clonable physical property of the carrier, and the method is used to manufacture the hardware tamper detection coating described in any of the above embodiments. Figure 4 As shown, the method includes:

[0053] S501: Mixing the insulating materials based on a preset ratio to obtain the substrate.

[0054] S503: randomly and uniformly placing the conductive particles in the substrate to obtain the hardware tampering detection coating.

[0055] S505: Uniformly apply the hardware tamper detection coating to the onboard component side of the printed circuit board.

[0056] S507: After the coated hardware tampering detection coating is left to stand at a preset temperature for a preset time, a detection electrode is disposed on the surface of the hardware tampering detection coating, wherein the detection electrode is used to detect the impedance of the hardware tampering detection coating.

[0057] In the embodiment of the present application, the insulating material is mixed based on a preset ratio to obtain a substrate. The preset ratio is determined according to the method of generating the insulating material. For example, if the insulating material is epoxy resin, the preset ratio may be 1:1, and the component A and the component B of the epoxy resin are mixed evenly in a ratio of 1:1 to form the substrate. Specifically, the insulating material may be AB glue.

[0058] Conductive particles are randomly and evenly placed in the substrate to obtain the hardware tampering detection coating. Specifically, the conductive particles are slowly placed in the evenly mixed AB glue. Furthermore, in order to ensure the random and uniform distribution of the particles in the substrate material, the random and uniform placement of the conductive particles in the substrate includes, based on at least one stirring method selected from manual stirring, mechanical stirring, and ultrasonic stirring, continuously stirring the substrate after the conductive particles are placed for a preset time. Specifically, the conductive particles in the substrate can be randomly and evenly distributed by any one of the stirring methods selected from manual stirring, mechanical stirring, and ultrasonic stirring. Of course, any two or three of the above stirring methods can also be mixed and stirred to make the conductive particles in the substrate randomly and evenly distributed.

[0059] The hardware tamper detection coating in which the conductive particles are evenly dispersed is evenly applied to the component-side surface of the printed circuit board. To ensure the uniformity of the hardware tamper detection coating, a process such as dip coating can be used to form a heterogeneous coating covering the printed circuit board.

[0060] After the coated hardware tamper detection coating is left standing for a preset time at a preset temperature, a detection electrode is set on the surface of the hardware tamper detection coating, and the detection electrode is used to detect the impedance of the hardware tamper detection coating. Specifically, the preset temperature can be room temperature, such as 25-27°C. After standing for a preset time, the hardware tamper detection coating is cured. The preset time is determined according to the characteristics of the insulating material of the substrate and the use environment, and can be 24 hours.

[0061] In some embodiments, Figure 5As shown, before the conductor particles are randomly and uniformly placed in the substrate, the method further includes:

[0062] In some embodiments, before the hardware tamper detection coating is uniformly applied to the onboard component side of the printed circuit board, the hardware tamper detection coating is placed in a vacuum degassing machine for degassing. In order to avoid the influence of bubbles on the performance of the hardware tamper detection coating, the hardware tamper detection coating is placed in a vacuum degassing machine for degassing, which can effectively remove bubbles generated during the mixing process of the conductor particles and the substrate, and ensure the consistency and stability of the hardware tamper detection coating.

[0063] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0064] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the", "these" and the like in this application do not represent quantitative restrictions, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusions; for example, a process, method and system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. Usually, the character " / " indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0065] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A hardware tamper detection coating based on the unclonable physical properties of a substrate, characterized in that: The hardware tamper detection coating is arranged on the onboard component side of the printed circuit board, and the hardware tamper detection coating comprises a substrate and conductor particles, wherein the substrate comprises an insulating material, and the conductor particles are randomly distributed in the substrate.

2. The hardware tamper detection coating according to claim 1, characterized in that: The conductive particles are uniformly distributed in the substrate.

3. The hardware tamper detection coating according to claim 1 or 2, characterized in that: The conductor particles are metal particles.

4. The hardware tamper detection coating according to claim 1 or 2, characterized in that: The diameter of the conductor particles is 500 nanometers to 0.5 millimeters.

5. The hardware tamper detection coating according to claim 1 or 2, characterized in that: The insulating material includes at least one of epoxy resin, silicone resin and acrylic resin.

6. The hardware tamper detection coating according to claim 1 or 2, characterized in that: One side of the hardware tamper detection coating is attached to the onboard component side of the printed circuit board, and the other side of the hardware tamper detection coating is provided with an electromagnetic shielding layer.

7. A method for manufacturing a hardware tamper detection coating based on the non-clonable physical properties of a carrier board, characterized in that: The method is used to manufacture the hardware tamper detection coating according to any one of claims 1 to 6, and the method comprises: Mixing the insulating materials based on a preset ratio to obtain the substrate; randomly and uniformly placing the conductive particles in the substrate to obtain the hardware tamper detection coating; uniformly applying the hardware tamper detection coating to the onboard component side of the printed circuit board; After the coated hardware tampering detection coating is left to stand at a preset temperature for a preset period of time, a detection electrode is arranged on the surface of the hardware tampering detection coating, and the detection electrode is used to detect the impedance of the hardware tampering detection coating.

8. The method according to claim 7, characterized in that Randomly and uniformly placing the conductor particles in the substrate comprises: Based on at least one stirring method selected from manual stirring, mechanical stirring, and ultrasonic stirring, the substrate into which the conductive particles are placed is continuously stirred for a preset time period.

9. The method according to claim 7, characterized in that: Before the hardware tamper detection coating is evenly applied to the onboard component side of the printed circuit board, the method further includes: The hardware tamper detection coating is placed in a vacuum degassing machine for degassing treatment.

10. A printed circuit board, characterized in that: The onboard component side of the printed circuit board is provided with a hardware tamper detection coating as claimed in any one of claims 1 to 6.

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