Protection circuit and equipment for preventing side channel attack in wireless signal analysis

Abstract

The utility model discloses a protection circuit and equipment for preventing side channel attack in wireless signal analysis. The protection circuit comprises a secret key management unit, a wireless radio frequency unit, a first direct current converter and a second direct current converter, one end of the first direct-current converter and one end of the second direct-current converter are respectively connected with the power supply, and the power supply respectively inputs power supply current into the first direct-current converter and the second direct-current converter; the other end of the first direct current converter is connected with the wireless radio frequency unit; and the other end of the second direct current converter is connected with the key management unit. The first direct current converter is used for converting first power supply current output by the power supply into second power supply current required by the wireless radio frequency unit and supplying power to the wireless radio frequency unit; and the second direct current converter converts the first power supply current output by the power supply into third power supply current required by the key management unit and supplies power to the key management unit. And the reliability of side channel attack prevention is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of information security, and in particular to a protection circuit and equipment for preventing side channel attacks by wireless signal analysis. Background Art

[0002] As the name implies, a side channel attack is a method of obtaining additional information through unconventional information channels and obtaining secret information "indirectly". It is sometimes called a bypass attack. In practical applications, the cryptographic module in the electronic device to be protected will leak its internal state information in the form of energy consumption during operation. This information related to the key used by the cryptographic algorithm is called side information. The electronic devices to be protected are, for example, smart home devices and smart robots. In the process of attacking the cryptographic module, the attacker can use a variety of side information analysis techniques to recover secret information such as keys.

[0003] In the related art, there are two main methods to prevent side channel attacks: one is to change the side channel leakage characteristics of the encryption and decryption unit in the time dimension, which is mainly achieved by changing the execution time of the operation implemented by the encryption algorithm; the other is to hide the side channel leakage characteristics of the encryption unit in the amplitude dimension, which is mainly achieved by directly making the amount of side information of the operation performed by the encryption and decryption unit equal or random. However, the above two methods to prevent side channel attacks only increase the computational difficulty of side information analysis, and the key can still be deciphered through more complex side information analysis.

[0004] Considering that when the cryptographic module in the protection device performs key verification, the electromagnetic waves caused by the power supply voltage fluctuation are coupled to the radio frequency unit, forming a radio signal carrier and transmitting it, there is a risk of obtaining the wireless signal and filtering it to restore the carrier signal, and then calculating the energy change waveform to determine the key. At present, there is no more effective solution to the above risks, so the side channel attack prevention method in the related technology still has the problem of poor reliability. Utility Model Content

[0005] On the first aspect, the embodiments of the utility model provide a protection circuit and device for preventing side channel attacks by analyzing wireless signals, so as to solve the risk in the prior art of obtaining wireless signals for filtering and restoring the carrier signal, and then calculating the energy change waveform and determining the key. Therefore, the side channel attack prevention method still has the problem of poor reliability.

[0006] The embodiment of the utility model provides a protection circuit and device for preventing side channel attacks by wireless signal analysis, including: a key management unit, a wireless radio frequency unit, a first DC converter and a second DC converter; wherein:

[0007] One end of the first DC converter and one end of the second DC converter are respectively connected to the power supply, the other end of the first DC converter is connected to the wireless radio frequency unit; the other end of the second DC converter is connected to the key management unit;

[0008] The first DC converter is used to convert the first power supply current output by the power supply into a second power supply current required by the wireless radio frequency unit, and input the second power supply current into the wireless radio frequency unit to power the wireless radio frequency unit;

[0009] The second DC converter is used to convert the first power supply current output by the power supply into a third power supply current required by the key management unit, and input the third power supply current into the key management unit to supply power to the key management unit.

[0010] The embodiment of the utility model provides a protection circuit for preventing wireless signal analysis from performing side channel attacks, including: a key management unit, a wireless radio frequency unit, a first DC converter and a second DC converter; one end of the first DC converter and one end of the second DC converter are respectively connected to a power supply, and the power supply inputs the power supply current into the first DC converter and the second DC converter respectively; the other end of the first DC converter is connected to the wireless radio frequency unit; the other end of the second DC converter is connected to the key management unit. The first DC converter converts the first power supply current output by the power supply into the second power supply current required by the wireless radio frequency unit, and supplies power to the wireless radio frequency unit; the second DC converter converts the first power supply current output by the power supply into the third power supply current required by the key management unit, and supplies power to the key management unit. Thus, the power supply line of the key management unit is isolated from the power supply line of the wireless radio frequency unit. The utility model isolates the power supply line of the key management unit from the power supply line of the wireless radio frequency unit, and prevents the electromagnetic waves caused by the power supply voltage fluctuation when the password module performs key verification from being coupled to the radio frequency unit from the hardware, so as to form a radio signal carrier and transmit it out, and there is a risk of restoring the carrier signal by filtering the wireless signal, and then calculating the energy change waveform and determining the key. The key security, data security and privacy security of the user are effectively protected. Improved reliability against side-channel attacks.

[0011] In an optional embodiment, it further includes: a protection unit; wherein:

[0012] One end of the protection unit is connected to the power supply, and the other end is connected to one end of the first DC converter and one end of the second DC converter respectively;

[0013] The protection unit is used to perform overcurrent protection on the key management unit and the wireless radio frequency unit;

[0014] The first DC converter is used to convert the first power supply current output by the power supply and passing through the protection unit into a second power supply current required by the wireless radio frequency unit, and input the second power supply current into the wireless radio frequency unit to power the wireless radio frequency unit;

[0015] The second DC converter is used to convert the first power supply current output by the power supply and passing through the protection unit into a third power supply current required by the key management unit, and input the third power supply current into the key management unit to power the key management unit.

[0016] In the embodiment of the utility model, overcurrent protection for the key management unit and the wireless radio frequency unit is achieved by setting a protection unit.

[0017] In an optional embodiment, the protection unit includes: a fuse and a thyristor; wherein:

[0018] One end of the thyristor is grounded; one end of the fuse is connected to the power supply; an ungrounded end of the thyristor and an end of the fuse not connected to the power supply are respectively connected to one end of the first DC converter and one end of the second DC converter.

[0019] In an optional embodiment, the first DC converter and the second DC converter respectively include: a DC-DC direct current-to-direct current converter.

[0020] In an optional embodiment, the first DC converter includes: a first capacitor, a first resistor, a second capacitor, a first DC-DC chip, a first inductor, a second resistor, a third resistor and a third capacitor; wherein:

[0021] One end of the first capacitor is grounded; one end of the second capacitor is grounded; the ungrounded end of the thyristor in the protection unit and the end of the fuse that is not connected to the power supply are connected to the ungrounded end of the first capacitor; the ungrounded end of the second capacitor is respectively connected to one end of the first resistor and the EN pin of the first DC-DC chip; the ungrounded end of the first capacitor is also connected to the other end of the first resistor; the end of the first resistor connected to the first capacitor is also connected to the VIN pin of the first DC-DC chip; the GND pin of the first DC-DC chip is grounded; the SW pin of the first DC-DC chip is connected to one end of the first inductor; the other end of the first inductor is respectively connected to one end of the second resistor and one end of the third capacitor; the other end of the third capacitor is grounded; one end of the third resistor is grounded; the other end of the third resistor is respectively connected to one end of the second resistor that is not connected to the first inductor and the FB pin of the first DC-DC chip; the ungrounded end of the third capacitor is also connected to the wireless radio frequency unit.

[0022] In an optional embodiment, the second DC converter includes: a fourth capacitor, a fourth resistor, a fifth capacitor, a second DC-DC chip, a second inductor, a fifth resistor, a sixth resistor and a sixth capacitor; wherein:

[0023] One end of the fourth capacitor is grounded; one end of the fifth capacitor is grounded; the ungrounded end of the thyristor in the protection unit and the end of the fuse that is not connected to the power supply are connected to the ungrounded end of the fourth capacitor; the ungrounded end of the fifth capacitor is respectively connected to one end of the fourth resistor and the EN pin of the second DC-DC chip; the ungrounded end of the fourth capacitor is also connected to the other end of the fourth resistor; the end of the fourth resistor connected to the fourth capacitor is also connected to the VIN pin of the second DC-DC chip; the GND pin of the second DC-DC chip is grounded; the SW pin of the second DC-DC chip is connected to one end of the second inductor; the other end of the second inductor is respectively connected to one end of the fifth resistor and one end of the sixth capacitor; the other end of the sixth capacitor is grounded; one end of the sixth resistor is grounded; the other end of the sixth resistor is respectively connected to one end of the fifth resistor that is not connected to the second inductor and the FB pin of the second DC-DC chip; the ungrounded end of the sixth capacitor is also connected to the key management unit.

[0024] In an optional embodiment, a third inductor is connected between a ground terminal of the first DC converter and a ground terminal of the second DC converter.

[0025] In a second aspect, an embodiment of the utility model provides an electronic device, comprising the above-mentioned protection circuit for preventing side channel attacks through wireless signal analysis; wherein the wiring of the power supply, the wiring of the key management unit and the wiring of the wireless radio frequency unit are on different circuit board layers.

[0026] By wiring the power supply, key management unit, and wireless radio frequency unit on different circuit board layers, we can further prevent electromagnetic waves caused by power supply voltage fluctuations from coupling to the radio frequency unit when the cryptographic module performs key verification, forming a radio signal carrier and transmitting it out. There is a risk of filtering and restoring the carrier signal by acquiring the wireless signal, and then calculating the energy change waveform and determining the key. This improves the reliability of preventing side channel attacks.

[0027] In an optional embodiment, a ground via is inserted into the area of ​​the circuit board where the wireless radio frequency unit is located.

[0028] By inserting ground vias in the area where the wireless radio unit is located on the circuit board, ground current loops can be prevented, thereby reducing parasitic ground inductance. The ground vias can also prevent the signal line of the wireless radio unit from cross-coupling with other signal lines on the circuit board, further improving the reliability of preventing side channel attacks.

[0029] In an optional embodiment, it includes: a first shielding cover surrounding the key management unit and a second shielding cover surrounding the wireless radio frequency unit.

[0030] The first shielding cover can prevent electromagnetic waves caused by power supply voltage fluctuations when the key management unit performs key verification from radiating out of the key management unit; the second shielding cover can prevent electromagnetic waves caused by power supply voltage fluctuations when the key management unit performs key verification from radiating into the wireless radio frequency unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A schematic diagram of the energy trace signal waveform and the key correspondence provided for the related technology;

[0033] Figure 2 A schematic diagram of a protection circuit for preventing side channel attacks from wireless signal analysis provided by the utility model;

[0034] Figure 3A schematic diagram of a protection circuit for preventing side channel attacks from wireless signal analysis provided by the utility model;

[0035] Figure 4 A circuit diagram of the protection unit provided by the utility model;

[0036] Figure 5 A circuit diagram of a first DC converter provided by the utility model;

[0037] Figure 6 A circuit diagram of a second DC converter provided by the utility model;

[0038] Figure 7 A schematic diagram of a protection circuit for preventing side channel attacks from wireless signal analysis provided by the utility model;

[0039] Figure 8 It is a schematic diagram of a power supply scheme in the related art;

[0040] Fig. 9 A schematic diagram of a power supply scheme provided by the utility model;

[0041] Fig.10 A schematic diagram of an electronic device provided by the utility model;

[0042] Fig.11 A schematic diagram of the layout of the radio frequency transmission lines provided by the utility model;

[0043] Fig.12 This is a schematic diagram of the placement of the first bypass capacitor provided by the utility model;

[0044] Fig.13 A schematic diagram of the placement of the second bypass capacitor provided by the utility model;

[0045] Fig.14 A schematic diagram of a grounding via provided by the utility model;

[0046] Fig.15 This is a schematic diagram of the digital circuit part and the analog radio frequency circuit part of the circuit board provided by the utility model. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and the like mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0049] In order to protect the user's information security, the plaintext data sent by the electronic device will be encrypted according to the key when passing through the key management unit to encrypt the plaintext data and form ciphertext data. However, in the process of encrypting the plaintext data, energy changes will occur. By obtaining the energy changes in the encryption process and using the energy analysis attack method, external personnel can decipher the key used by the encryption unit, thereby recovering the user information and causing the user information to be leaked.

[0050] In the related art, electromagnetic waves caused by power supply voltage fluctuations during key verification are coupled to the wireless radio frequency unit, forming a wireless signal carrier to be transmitted, especially wireless signals such as WiFi and Bluetooth. The wireless signal is obtained and filtered to restore the carrier signal, and then the energy change waveform is calculated, and the flip of the secret key '1' is calculated, so as to analyze and calculate the risk of the key. The utility model isolates the password management unit from the power supply line of the wireless radio frequency unit, thereby preventing the change of external energy consumption caused by key verification from the hardware, and then forms a wireless carrier, and then calculates the key based on the restored waveform analysis, effectively protecting the user's key security, data security and privacy security.

[0051] The basic principle of radio signal analysis attack: electromagnetic attack is carried out on radio transceivers (WiFi, Bluetooth), and the "AES noise" entrained in the radio Screaming Channel is used to recover the key. When verifying the key, the power supply voltage fluctuation noise and electromagnetic radiation are generated to couple to wireless radio frequency units such as WiFi and Bluetooth, forming the "AES noise" entrained in the WiFi and Bluetooth signals and transmitting them out. By acquiring the wireless signal and filtering it, the "AES noise" signal is restored, and then the energy change waveform is calculated.

[0052] The basic principle of SPA (Simple Power Analysis) attack is: Pt=Po+Pd+Pe+Pc, where Pt is the total energy consumption of the electronic device; Po is the operation component in the energy trace that depends on the operation performed by the electronic device, that is, the operation-dependent component, where the energy trace is a sampled signal of the energy consumption of the electronic device; Pd is the data component in the energy trace that depends on the processing of the electronic device, that is, the data-dependent component; Pe is electronic noise that is independent of the operation and data; and Pc is a constant that is independent of the operation and data.

[0053] When performing SPA attacks, each data bit in the key corresponds to a different operation, and different operations will leak side information of the key, that is, the key can be recovered according to the operation-dependent component Po. Taking the modular exponent in the RSA algorithm as an example, in the process of calculating the modular exponent "md mod n", the modular square calculation and modular multiplication calculation depend on whether the value of the corresponding bit of the private key "d" is 0 or 1. If it is 0, the modular square calculation is performed, and if it is 1, the modular multiplication calculation is performed.

[0054] The computation time of the two computation operations is significantly different, forming two different patterns in the energy trace signal. Based on this, the values ​​of all bits of the private key can be recovered by observing the two patterns appearing in the energy trace, and thus the private key can be recovered. Figure 1 A schematic diagram of the energy trace signal waveform and the key corresponding to the related technology is provided, such as Figure 1 As shown in the figure, during the execution of modular exponentiation in the RSA algorithm, the sequential operations are "SS SM SM SSS SM SS SM SM SSS". Here, "S" represents the modular square operation, and the corresponding bit value is 0; "SM" represents the modular multiplication operation, and the corresponding bit value is 1, so the private key used by the RSA algorithm is "001100010011000".

[0055] In the related art, there are two main methods to prevent side channel attacks: one is to change the side channel leakage characteristics of the encryption and decryption unit in the time dimension, which is mainly achieved by changing the execution time of the operation implemented by the encryption algorithm; the other is to hide the side channel leakage characteristics of the encryption unit in the amplitude dimension, which is mainly achieved by directly making the amount of side information of the operation performed by the encryption and decryption unit equal or random. However, the above two methods to prevent side channel attacks only increase the computational difficulty of side information analysis, and the key can still be deciphered through more complex side information analysis.

[0056] Considering that the key management unit causes power supply voltage fluctuation noise and generates electromagnetic radiation that couples to wireless radio frequency units such as WiFi and Bluetooth during key verification, forming "AES noise" entrained in WiFi and Bluetooth signals and emitting them, there is a risk of obtaining wireless signals, filtering and processing them to restore the "AES noise" signal, and then calculating the energy change waveform, calculating the flip of the secret key '1', and thus analyzing and calculating the key. Therefore, the utility model provides a protection circuit and device for preventing wireless signal analysis from side channel attacks. It is used to solve the problem of poor reliability of the side channel attack prevention method in the related art.

[0057] The solution provided by the embodiment of the utility model is described in detail below with reference to the accompanying drawings.

[0058] Figure 2 A schematic diagram of a protection circuit for preventing side channel attacks from wireless signal analysis provided by the utility model includes: a key management unit 11, a wireless radio frequency unit 12, a first DC converter 13 and a second DC converter 14; wherein:

[0059] One end of the first DC converter 13 and one end of the second DC converter 14 are respectively connected to the power supply, the other end of the first DC converter 13 is connected to the wireless radio frequency unit 12; the other end of the second DC converter 14 is connected to the key management unit 11;

[0060] The first DC converter 13 is used to convert the first power supply current output by the power supply into a second power supply current required by the wireless radio frequency unit 12, and input the second power supply current into the wireless radio frequency unit 12 to supply power to the wireless radio frequency unit 12;

[0061] The second DC converter 14 is used to convert the first power supply current output by the power supply into a third power supply current required by the key management unit 11, and input the third power supply current into the key management unit 11 to supply power to the key management unit 11.

[0062] The embodiment of the utility model provides a protection circuit for preventing side channel attacks by wireless signal analysis, comprising: a key management unit 11, a wireless radio frequency unit 12, a first DC converter 13 and a second DC converter 14; one end of the first DC converter 13 and one end of the second DC converter 14 are respectively connected to a power supply, and the power supply inputs the supply current into the first DC converter 13 and the second DC converter 14 respectively; the other end of the first DC converter 13 is connected to the wireless radio frequency unit 12; the other end of the second DC converter 14 is connected to the key management unit 11.

[0063] The power supply current required by the key management unit 11 itself may be the same as or different from the power supply current output by the power supply. The function of the second DC converter 14 is to convert the first power supply current output by the power supply into the third power supply current required by the key management unit 11, and to supply power to the key management unit 11. The power supply current required by the wireless radio frequency unit may be the same as or different from the power supply current output by the power supply. The function of the first DC converter 13 is to convert the first power supply current output by the power supply into the second power supply current required by the wireless radio frequency unit 12, and to supply power to the wireless radio frequency unit 12. The above hardware design is used to isolate the power supply line of the key management unit 11 from the power supply line of the wireless radio frequency unit 12.

[0064] The utility model isolates the power supply circuit of the key management unit 11 from the power supply circuit of the wireless radio frequency unit 12, thereby preventing electromagnetic waves caused by power supply voltage fluctuations when the password module performs key verification from coupling to the radio frequency unit, forming a radio signal carrier and transmitting it out, which may cause the risk of restoring the carrier signal by filtering the wireless signal, and then calculating the energy change waveform to determine the key. The user's key security, data security and privacy security are effectively protected, and the reliability of preventing side channel attacks is improved.

[0065] Figure 3 The schematic diagram of the protection circuit for preventing the wireless signal analysis from performing side channel attacks provided by the utility model also includes: a protection unit 15; wherein:

[0066] One end of the protection unit 15 is connected to the power supply, and the other end is connected to one end of the first DC converter 13 and one end of the second DC converter 14 respectively;

[0067] The protection unit 15 is used to perform overcurrent protection on the key management unit 11 and the wireless radio frequency unit 12;

[0068] The first DC converter 13 is used to convert the first power supply current output by the power supply through the protection unit 15 into a second power supply current required by the wireless radio frequency unit 12, and input the second power supply current into the wireless radio frequency unit 12 to power the wireless radio frequency unit 12;

[0069] The second DC converter 14 is used to convert the first power supply current output by the power supply through the protection unit 15 into a third power supply current required by the key management unit 11, and input the third power supply current into the key management unit 11 to power the key management unit 11.

[0070] By setting the protection unit 15, overcurrent protection is implemented for the key management unit 11 and the wireless radio frequency unit 12. In addition, the power supply current output by the power supply first passes through the protection unit 15, and then is input into the first DC converter 13 and the second DC converter 14 respectively. The first DC converter 13 is used to convert the first power supply current output by the power supply through the protection unit 15 into the third power supply current required by the wireless radio frequency unit 12, and supply power to the wireless radio frequency unit 13. The second DC converter 14 is used to convert the first power supply current output by the power supply through the protection unit 15 into the second power supply current required by the key management unit 11, and supply power to the key management unit 11.

[0071] Figure 4 The circuit diagram of the protection unit provided by the utility model includes a fuse F and a thyristor D; wherein:

[0072] One end of the thyristor D is grounded; one end of the fuse F is connected to the power supply; the ungrounded end of the thyristor D and the end of the fuse F not connected to the power supply are respectively connected to one end of the first DC converter 13 and one end of the second DC converter 14.

[0073] In the above circuit, the fuse F (fuse) mainly plays an overload protection role. If the fuse F is correctly placed in the circuit, the fuse F will melt and cut off the current when the current abnormally rises to a certain height and temperature, thus protecting the safe operation of the circuit and realizing overcurrent protection for the key management unit and the wireless radio unit.

[0074] The main function of thyristor D in the circuit is to achieve controlled rectification. When a positive voltage is applied between the cathode and anode of thyristor D and no signal is applied to the control electrode, thyristor D is in the off state. If a small positive voltage is applied between the control electrode and the cathode, thyristor D will be turned on. At this time, even if the control signal is removed, thyristor D can still remain turned on unless the anode power supply circuit is disconnected or the anode current is reduced to less than the holding current of thyristor D. Under normal circumstances, the current required to trigger thyristor D is equal to 1 / 100 to 1 / 1000 of the current flowing through thyristor D. When thyristor D is connected in series to the secondary winding of the arc welding transformer and the welding cable, it can not only convert AC into DC, but also control the size of the welding current with the cooperation of the corresponding electronic device. Thyristor D has only two working states, namely, on and off, and the current can only be adjusted by adjusting the conduction point (trigger angle) of thyristor D. The earlier the conduction time of thyristor D, the greater the power output to the load.

[0075] During the operation of thyristor D, its anode (A) and cathode (K) are connected to the power supply and load to form the main circuit of thyristor D. The gate G and cathode K of thyristor D are connected to the device for controlling the thyristor to form the control circuit of thyristor D. Thyristor D is a semi-controlled power electronic device. Its working conditions include: when thyristor D is subjected to reverse anode voltage, no matter what voltage the gate is subjected to, thyristor D is in reverse blocking state. When thyristor D is subjected to positive anode voltage, the thyristor is turned on only when the gate is subjected to positive voltage. At this time, thyristor D is in forward conduction state, which is the thyristor current characteristic of thyristor D, i.e., controllable characteristic. When thyristor D is turned on, as long as there is a certain positive anode voltage, no matter what the gate voltage is, thyristor D remains turned on, that is, after thyristor D is turned on, the gate loses its function. The gate only plays a triggering role. When thyristor D is turned on, when the main circuit voltage (or current) decreases to near zero, thyristor D is turned off.

[0076] In the embodiment of the utility model, the first DC converter and the second DC converter respectively include: a DC-DC direct current-to-direct current converter.

[0077] The DC-DC converter can convert any DC voltage into the required DC voltage.

[0078] Figure 5 A circuit diagram of a first DC converter provided in an embodiment of the utility model includes: a first capacitor C1, a first resistor R1, a second capacitor C2, a first DC-DC chip U1, a first inductor L1, a second resistor R2, a third resistor R3 and a third capacitor C3; wherein:

[0079] One end of the first capacitor C1 is grounded; one end of the second capacitor C2 is grounded; the ungrounded end of the thyristor D in the protection unit and the end of the fuse F that is not connected to the power supply are connected to the ungrounded end of the first capacitor C1; the ungrounded end of the second capacitor C2 is respectively connected to one end of the first resistor R1 and the EN pin of the first DC-DC chip U1; the ungrounded end of the first capacitor C1 is also connected to the other end of the first resistor R1; the end of the first resistor R1 connected to the first capacitor C1 is also connected to the VIN pin of the first DC-DC chip U1 ; The GND pin of the first DC-DC chip U1 is grounded; the SW pin of the first DC-DC chip U1 is connected to one end of the first inductor L1; the other end of the first inductor L1 is respectively connected to one end of the second resistor R2 and one end of the third capacitor C3; the other end of the third capacitor C3 is grounded; one end of the third resistor R3 is grounded; the other end of the third resistor R3 is respectively connected to one end of the second resistor R2 that is not connected to the first inductor L1 and the FB pin of the first DC-DC chip U1; the ungrounded end of the third capacitor C3 is also connected to the wireless radio frequency unit 12.

[0080] pass Figure 5 The circuit of the first DC converter shown can convert the first power supply current output by the power supply power source into the second power supply current required by the wireless radio frequency unit, and input the second power supply current into the wireless radio frequency unit to power the wireless radio frequency unit; or can convert the first power supply current output by the power supply power source and passed through the protection unit into the second power supply current required by the wireless radio frequency unit, and input the second power supply current into the wireless radio frequency unit to power the wireless radio frequency unit.

[0081] Figure 6 A circuit diagram of a second DC converter provided by an embodiment of the utility model includes: a fourth capacitor C4, a fourth resistor R4, a fifth capacitor C5, a second DC-DC chip U2, a second inductor L2, a fifth resistor R5, a sixth resistor R6 and a sixth capacitor C6; wherein:

[0082] One end of the fourth capacitor C4 is grounded; one end of the fifth capacitor C5 is grounded; the ungrounded end of the thyristor D in the protection unit and the end of the fuse F that is not connected to the power supply are connected to the ungrounded end of the fourth capacitor C4; the ungrounded end of the fifth capacitor C5 is respectively connected to one end of the fourth resistor R4 and the EN pin of the second DC-DC chip U2; the ungrounded end of the fourth capacitor C4 is also connected to the other end of the fourth resistor R4; the end of the fourth resistor R4 connected to the fourth capacitor C4 is also connected to the VIN pin of the second DC-DC chip U2 ; The GND pin of the second DC-DC chip U2 is grounded; the SW pin of the second DC-DC chip U2 is connected to one end of the second inductor L2; the other end of the second inductor L2 is respectively connected to one end of the fifth resistor R5 and one end of the sixth capacitor C6; the other end of the sixth capacitor C6 is grounded; one end of the sixth resistor R6 is grounded; the other end of the sixth resistor R6 is respectively connected to one end of the fifth resistor R5 that is not connected to the second inductor L2 and the FB pin of the second DC-DC chip U2; the end of the sixth capacitor C6 that is not grounded is also connected to the key management unit 11.

[0083] pass Figure 6 The circuit of the second DC converter shown in the figure converts the first power supply current output by the power supply power supply into the third power supply current required by the key management unit, and inputs the third power supply current into the key management unit to power the key management unit; or converts the first power supply current output by the power supply power supply and passed through the protection unit into the third power supply current required by the key management unit, and inputs the third power supply current into the key management unit to power the key management unit.

[0084] Figure 7 A schematic diagram of a protection circuit for preventing side channel attacks through wireless signal analysis provided by an embodiment of the utility model, wherein a third inductor L3 is connected between the ground terminal of the first DC converter and the ground terminal of the second DC converter.

[0085] A third inductor L3 is connected between the ground terminal of the first DC converter and the ground terminal of the second DC converter, which can further prevent electromagnetic waves caused by power supply voltage fluctuations during key verification from coupling to the RF unit and forming a radio signal carrier to be transmitted.

[0086] Figure 8 Schematic diagram of power supply scheme in related technology, such as Figure 8As shown, in the related art, due to the high integration of SOC and the cost considerations, most designs of consumer electronics use one power supply for the entire board. That is, it includes a protection unit, a DC converter, a key management unit (digital circuit) and a wireless radio unit (WIFI / BT wireless unit). The protection unit is connected to the power supply and the DC converter respectively, and the DC converter is also connected to the key management unit and the wireless radio unit respectively. Fig. 9 The schematic diagram of the power supply scheme provided by the utility model includes a protection unit, a first DC converter, a second DC converter, a key management unit and a wireless radio frequency unit. The protection unit is connected to the power supply, the first DC converter and the second DC converter respectively, the first DC converter is also connected to the wireless radio frequency unit, and the second DC converter is also connected to the key management unit. Fig. 9 As shown, the key management unit and the wireless radio frequency unit are powered separately, and the digital ground of the key management unit and the analog ground of the wireless radio frequency unit are also isolated. The single-board 5V power supply is connected to the DC-DC power input terminal corresponding to the wireless radio frequency unit, and after DC-DC conversion, it outputs a 3.3V power supply to power the wireless radio frequency unit; the single-board 5V power supply is also connected to the DC-DC power input terminal corresponding to the key management unit, and after DC-DC conversion, it outputs a 3.3V power supply to power the key management unit. In this design, the 3.3V power supply of the wireless radio frequency unit and the 3.3V power supply of the key management unit are isolated through DC-DC power conversion, and will not interfere with each other, and will not couple the "AES noise" to the radio frequency signal through the power supply.

[0087] The utility model isolates the key management unit from the power supply wiring of the wireless radio frequency unit, thereby preventing the change of external energy consumption caused by key verification from the hardware point of view, thereby forming a wireless carrier and calculating the key based on the restored waveform analysis.

[0088] In addition, when laying out the wiring, it is also necessary to prevent conducted crosstalk, which is an interference signal transmitted through the conduction path between circuit elements. The information of the key operation will also be coupled to the RF unit through the power supply and signal routing, and the WiFi and Bluetooth signals will be transmitted as carriers. The signal coupled to the wireless signal is used to restore the energy consumption waveform during the key operation, and then the key is calculated.

[0089] In response to the above problems, this design not only reconstructs the power supply scheme, separates the power supply of the key management unit and the wireless radio unit, but also isolates the ground of the two units and connects them together through inductance. In addition, this utility model also adopts a series of crosstalk suppression designs, such as adding an isolation layer, optimizing the circuit layout, and improving the anti-interference ability.

[0090] An embodiment of the utility model provides an electronic device, comprising: a protection circuit for preventing wireless signal analysis from performing side channel attacks; wherein the wiring of the power supply, the wiring of the key management unit, and the wiring of the wireless radio frequency unit are on different circuit board layers.

[0091] By wiring the power supply, key management unit, and wireless radio frequency unit on different circuit board layers, we can further prevent electromagnetic waves caused by power supply voltage fluctuations from coupling to the radio frequency unit when the cryptographic module performs key verification, forming a radio signal carrier and transmitting it out. There is a risk of filtering and restoring the carrier signal by acquiring the wireless signal, and then calculating the energy change waveform and determining the key. This improves the reliability of preventing side channel attacks.

[0092] A ground via is inserted into the area of ​​the circuit board where the wireless radio frequency unit is located.

[0093] By inserting ground vias in the area where the wireless radio unit is located on the circuit board, ground current loops can be prevented, thereby reducing parasitic ground inductance. The ground vias can also prevent the signal line of the wireless radio unit from cross-coupling with other signal lines on the circuit board, further improving the reliability of preventing side channel attacks.

[0094] Fig.10 The electronic device provided by the utility model includes: a first shielding cover 21 surrounding the key management unit 11 and a second shielding cover 22 surrounding the wireless radio frequency unit 12 .

[0095] The first shielding cover 21 can prevent electromagnetic waves caused by power supply voltage fluctuations when the key management unit 11 performs key verification from radiating out of the key management unit 11; the second shielding cover 22 can prevent electromagnetic waves caused by power supply voltage fluctuations when the key management unit 11 performs key verification from radiating into the wireless radio frequency unit 12.

[0096] The following rules are followed in the design and layout of the radio frequency (RF) printed circuit board (PCB) of the utility model, and the mixed signals such as digital (key management), analog (wireless radio frequency) and RF components on the PCB are divided into board functions, operating frequency bands, currents and voltages, types of key RF devices, EMC and related RF indicators, as well as stacking structure, impedance control, external structure size, shielding cavity, and cover size, etc.

[0097] Physical partitioning: Organize the main components according to the main signal flow regulations of the single board. Fix the device on the RF path according to the location of the RF port and change its direction to minimize the length of the RF path. Make each circuit sufficiently isolated, and use metal shielding to shield the RF in the circuit module with poor isolation or sensitive and strong radiation sources. In the RF area, the energy is shielded.

[0098] Electrical partition planning is divided into three parts: power, digital and analog. Spatial separation, layout and routing do not overlap areas. In addition, strong current signals and weak current signals, as well as digital signals and analog signals are distinguished. That is, circuits that perform the same function should be grouped within a specific range to reduce the signal loop area.

[0099] Fig.11 The utility model provides a schematic diagram of the layout of the radio frequency transmission line, including the first layer (top layer), the second layer (GND layer), the third layer (PWR layer) and the fourth layer (bottom layer). In order to transmit RF power to or from the IC pins on the PCB, the RF components require impedance-controlled transmission lines. These transmission lines may be hidden in the inner layer or implemented in the outer layer, that is, in the top layer or the bottom layer.

[0100] In addition, accidental coupling between the key reading signal and the RF signal needs to be avoided. The digital circuit, i.e. the key management unit power supply, needs to be designed separately from the wireless RF unit, and these signal lines should be routed on a different circuit board layer from the RF signal lines. Avoid digital noise from connecting to the RF signal line and modulating the RF carrier.

[0101] VCC / Power Lines: Dedicated layers should be used to route these lines. Appropriate decoupling / bypass capacitors should be placed at the main VCC distribution node and VCC branches. The frequency response of the entire RF IC needs to be considered when selecting bypass capacitors. These traces should also be separated from RF lines, which emit a lot of RF energy.

[0102] Because capacitors have a self-resonant frequency (SRF), the effective frequency range of capacitors is limited in reality. Above the SRF, capacitors become inductive and therefore have no decoupling or bypassing function.

[0103] Since the power line must be AC ​​grounded, it is very important to minimize the parasitic inductance of the AC ground loop. Parasitic inductance may be caused by component layout or orientation, such as the orientation of decoupling capacitors.

[0104] Fig.12 The first bypass capacitor placement diagram provided by the utility model includes a bypass capacitor, a via connected to a power plane, an isolation ground connected to the ground through a via, and an AC ground return current path. Fig.12 As shown in the figure, the power supply is filtered by the bypass capacitor and then connected to the power pin.

[0105] Fig.13 The second bypass capacitor placement diagram provided by the utility model includes a bypass capacitor, a via connected to a power plane, an isolation ground connected to the ground through a via, and an AC ground return current path. Fig.13 As shown, the power supply is directly connected to the power pin and then to the bypass capacitor.

[0106] In this configuration, the vias connecting the VCC pad on the top layer to the inner power plane (layer) can block the AC ground current return path, forcing a longer return path with higher parasitic inductance. Any AC current flowing into the VCC pin passes through the bypass capacitor, reaches its ground side, and then returns to the inner ground plane. In this configuration, the total footprint of the bypass capacitor and the associated vias is minimized.

[0107] In another configuration, the AC ground loop is not limited by the vias in the power area. Generally speaking, this configuration requires a slightly larger PCB area.

[0108] Use RF components and transmission lines on Layer 1, and solid (continuous) ground planes on Layer 2. Stripline and offset stripline require ground planes above and below the center conductor. These areas are fully allocated to ground and are not shared or allocated to signal or power nets.

[0109] A large number of ground vias should be inserted between different ground layers in the RF area of ​​the PCB. This can prevent ground current loops, thereby reducing parasitic ground inductance. Vias can also prevent RF signal lines from cross-coupling with other signal lines on the PCB. Fig.14 This is a schematic diagram of the grounding via provided by the utility model.

[0110] For the board layers assigned to system power (DC power) and ground, component loop currents need to be considered. The approach is to avoid routing signal lines between the power and ground layers of the board.

[0111] Metal isolation between two geographical areas (called PCB shielding) is used to control the induction and radiation of electric fields, magnetic fields and electromagnetic waves from one place to another. To prevent the spread of interfering electromagnetic fields, the interference source of components, circuits, components, cables or the entire system is surrounded by a PCB shielding cover; the receiving circuit, device or system is surrounded by a PCB shielding cover to prevent it from being affected by external electromagnetic fields. The digital circuit part and the analog RF circuit part are isolated by a shielding cover. Fig.15 This is a schematic diagram of the digital circuit part and the analog radio frequency circuit part of the circuit board provided by the utility model.

[0112] The utility model reconstructs the power supply scheme of a single board, separates the power supply, digital and analog spaces, and layouts and wires non-overlapping areas. It distinguishes between strong current signals and weak current signals, as well as digital signals and analog signals. Circuits that perform the same function should be grouped within a specific range to reduce the signal loop area. It prevents the electromagnetic radiation and energy consumption generated during key calculations from coupling to wireless signals, and transmits the wireless signal as a carrier, thereby reducing the noise of the wireless signal. The utility model does not change the key information encoding algorithm and does not increase the computing time cost. The utility model prevents side channel attacks by cutting off the crosstalk and coupling paths of electromagnetic signals, while also reducing the noise of wireless signals and improving the quality of wireless signals.

[0113] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0114] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A protection circuit for preventing side channel attacks from wireless signal analysis, characterized in that: include: A key management unit, a wireless radio frequency unit, a first DC converter and a second DC converter; wherein: One end of the first DC converter and one end of the second DC converter are respectively connected to the power supply, the other end of the first DC converter is connected to the wireless radio frequency unit; the other end of the second DC converter is connected to the key management unit; The first DC converter is used to convert the first power supply current output by the power supply into a second power supply current required by the wireless radio frequency unit, and input the second power supply current into the wireless radio frequency unit to power the wireless radio frequency unit; The second DC converter is used to convert the first power supply current output by the power supply into a third power supply current required by the key management unit, and input the third power supply current into the key management unit to supply power to the key management unit.

2. The circuit according to claim 1, characterized in that Also includes: Protection unit; wherein: One end of the protection unit is connected to the power supply, and the other end is connected to one end of the first DC converter and one end of the second DC converter respectively; The protection unit is used to perform overcurrent protection on the key management unit and the wireless radio frequency unit; The first DC converter is used to convert the first power supply current output by the power supply and passing through the protection unit into a second power supply current required by the wireless radio frequency unit, and input the second power supply current into the wireless radio frequency unit to power the wireless radio frequency unit; The second DC converter is used to convert the first power supply current output by the power supply and passing through the protection unit into a third power supply current required by the key management unit, and input the third power supply current into the key management unit to power the key management unit.

3. The circuit according to claim 2, characterized in that The protection unit comprises: a fuse and a thyristor; wherein: One end of the thyristor is grounded; one end of the fuse is connected to the power supply; the ungrounded end of the thyristor and the end of the fuse not connected to the power supply are respectively connected to one end of the first DC converter and one end of the second DC converter.

4. The circuit according to claim 3, characterized in that The first DC converter and the second DC converter include: a DC-DC converter.

5. The circuit according to claim 4, characterized in that The first DC converter includes: a first capacitor, a first resistor, a second capacitor, a first DC-DC chip, a first inductor, a second resistor, a third resistor and a third capacitor; wherein: One end of the first capacitor is grounded; one end of the second capacitor is grounded; the ungrounded end of the thyristor in the protection unit and the end of the fuse that is not connected to the power supply are connected to the ungrounded end of the first capacitor; the ungrounded end of the second capacitor is respectively connected to one end of the first resistor and the EN pin of the first DC-DC chip; the ungrounded end of the first capacitor is also connected to the other end of the first resistor; the end of the first resistor connected to the first capacitor is also connected to the VIN pin of the first DC-DC chip; the GND pin of the first DC-DC chip is grounded; the SW pin of the first DC-DC chip is connected to one end of the first inductor; the other end of the first inductor is respectively connected to one end of the second resistor and one end of the third capacitor; the other end of the third capacitor is grounded; one end of the third resistor is grounded; the other end of the third resistor is respectively connected to one end of the second resistor that is not connected to the first inductor and the FB pin of the first DC-DC chip; the ungrounded end of the third capacitor is also connected to the wireless radio frequency unit.

6. The circuit according to claim 4, characterized in that The second DC converter includes: a fourth capacitor, a fourth resistor, a fifth capacitor, a second DC-DC chip, a second inductor, a fifth resistor, a sixth resistor and a sixth capacitor; wherein: One end of the fourth capacitor is grounded; one end of the fifth capacitor is grounded; the ungrounded end of the thyristor in the protection unit and the end of the fuse that is not connected to the power supply are connected to the ungrounded end of the fourth capacitor; the ungrounded end of the fifth capacitor is respectively connected to one end of the fourth resistor and the EN pin of the second DC-DC chip; the ungrounded end of the fourth capacitor is also connected to the other end of the fourth resistor; the end of the fourth resistor connected to the fourth capacitor is also connected to the VIN pin of the second DC-DC chip; the GND pin of the second DC-DC chip is grounded; the SW pin of the second DC-DC chip is connected to one end of the second inductor; the other end of the second inductor is respectively connected to one end of the fifth resistor and one end of the sixth capacitor; the other end of the sixth capacitor is grounded; one end of the sixth resistor is grounded; the other end of the sixth resistor is respectively connected to one end of the fifth resistor that is not connected to the second inductor and the FB pin of the second DC-DC chip; the ungrounded end of the sixth capacitor is also connected to the key management unit.

7. The circuit according to claim 5 or 6, characterized in that A third inductor is connected between the ground terminal of the first DC converter and the ground terminal of the second DC converter.

8. An electronic device, characterized in that: include: A protection circuit for preventing side channel attacks by wireless signal analysis as described in any one of claims 1 to 7; wherein the wiring of the power supply, the wiring of the key management unit, and the wiring of the wireless radio frequency unit are on different circuit board layers.

9. The electronic device according to claim 8, characterized in that: A ground via is inserted into the area of ​​the circuit board where the wireless radio frequency unit is located.

10. The electronic device according to claim 8, characterized in that: include: A first shielding cover surrounding the key management unit and a second shielding cover surrounding the wireless radio frequency unit.

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