Power supply isolation device and isolation method for preventing side-channel attacks

Abstract

The application discloses a power supply isolation device and method for preventing side channel attacks, the power supply isolation device comprising a first energy storage module, a first switch module, a clock gating module, and a control module, the control module outputting control signals to the first switch module and the clock gating module respectively, so as to control the clock gating module to stop outputting working clock signals in the case of external power supply, and control the clock gating module to output working clock signals in the case of stopping external power supply; the technical scheme controls the power supply switching of the external power supply and the energy storage module, and synchronously controls the start and stop of the clock signals, so that the protected circuit only runs in the state of being isolated from the external power supply and being powered by the energy storage module, thereby effectively cutting off the side channel leakage paths of power supply, current, power consumption, electromagnetism, and time sequence, realizing the hardware-level protection against side channel attacks, and significantly improving the security and anti-analysis capability of the protected circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of information security technology, and in particular to a power supply isolation device and method for preventing side channel attacks. BACKGROUND

[0002] With the increasing importance of information security in various electronic devices, encryption chips have become the key to ensuring data security. However, in the running process of traditional encryption and decryption chips, side channel information related to internal operation may be leaked, such as current change, power consumption change, electromagnetic radiation characteristics or running timing information. Attackers can infer the key or algorithm characteristics in the encryption and decryption process by sampling and analyzing these side channel signals, forming a so-called side channel attack. In the prior art, to prevent side channel attacks, a perturbation mechanism is usually introduced in the chip circuit, such as introducing randomness in the design of the chip circuit, or injecting noise signals to interfere with the attacker's sampling during normal operation. However, such protection mechanisms still have limitations, on the one hand, they introduce additional power consumption and complexity, on the other hand, the perturbation pattern itself can also be identified and circumvented by attackers, thereby weakening the protection effect. SUMMARY

[0003] The embodiments of the present application provide a power supply isolation device and method for preventing side channel attacks, which isolate the operation of the power supply and the chip circuit. The working current and power consumption of the chip circuit cannot be measured, further lacking data support for electromagnetic analysis, to fundamentally isolate the approach of side channel attacks.

[0004] The first aspect of the embodiments of the present application provides a power supply isolation device for preventing side channel attacks, comprising:

[0005] A first energy storage module for storing electrical energy and releasing electrical energy to a protected circuit;

[0006] A first switch module having one end connected to an external power supply, the other end of the first switch module being connected to the first energy storage module and the protected circuit respectively, for enabling the external power supply to supply power or stop supplying power to the first energy storage module and the protected circuit according to a control signal;

[0007] A clock gating module connected to the protected circuit, for providing or not providing a working clock signal to the protected circuit according to the control signal;

[0008] a control module connected to the first switch module and the clock gating module respectively, configured to output a control signal to the first switch module and the clock gating module respectively, so as to control the clock gating module to stop outputting a working clock signal and make the protected circuit stop working when the external power supply is powered, and control the clock gating module to output the working clock signal and make the protected circuit in a working state when the external power supply stops supplying power and the first energy storage module supplies power to the protected circuit.

[0009] Optionally, the second input end of the clock gating module receives an external clock signal, and the first input end of the clock gating module receives the control signal, so as to output the working clock signal when the control signal is in a first level state, and stop outputting the working clock signal when the control signal is in a second level state.

[0010] Optionally, the clock gating module comprises a NOT gate and an AND gate, the first input end of the AND gate is the first input end of the clock gating module, the input end of the NOT gate is the second input end of the clock gating module, the output end of the NOT gate is connected to the second input end of the AND gate, and the output end of the AND gate is the output end of the clock gating module.

[0011] Optionally, the power isolation device further comprises:

[0012] a second switch module, one end of the second switch module being connected to the first energy storage module, the other end of the second switch module being grounded, and the control end of the second switch module being connected to the control module;

[0013] when the control module controls the first switch module and the second switch module to be turned on, the external power supply, the first switch module, the first energy storage module and the second switch module form a first power supply loop;

[0014] when the control module controls the first switch module and the second switch module to be turned off, the first energy storage module forms a second power supply loop.

[0015] Optionally, the first energy storage module is a capacitor arranged inside a chip, and the control module is further configured to output a control signal to the first switch module according to parameters of the capacitor and parameters of the protected circuit, so as to control the first switch module to be turned on to charge the capacitor before the voltage of the capacitor reaches a minimum working voltage of the chip, and control the first switch module to be turned off when the voltage of the capacitor reaches a maximum working voltage of the chip, so as to make the capacitor supply power to the protected circuit inside the chip.

[0016] Optionally, the control module calculates the charging time and discharging time of the capacitor according to the parameters of the capacitor and the parameters of the protected circuit, and outputs a control signal to the first switch module according to the charging time and the discharging time.

[0017] Optionally, the capacitor is integrated inside a chip of the protected circuit, and the capacitor is a metal-insulator-metal capacitor or a metal-oxide-metal capacitor.

[0018] The second aspect of the embodiment of the present application provides an isolation method of the power supply isolation device for preventing side channel attacks, and the isolation method comprises:

[0019] The control signal is output to the first switch module and the clock gating module respectively, so that the clock gating module stops outputting a working clock signal to control the protected circuit to stop working when the external power supply is powered, and the clock gating module outputs the working clock signal to control the protected circuit to be in a working state when the external power supply stops supplying power and the first energy storage module supplies power to the protected circuit.

[0020] Optionally, the first energy storage module is a capacitor arranged inside a chip.

[0021] The isolation method further comprises:

[0022] The control signal is output to the first switch module according to the parameters of the capacitor and the parameters of the protected circuit, so that the voltage of the capacitor controls the first switch module to be turned on to charge the capacitor before the voltage of the capacitor reaches the minimum working voltage of the chip, and the voltage of the capacitor controls the first switch module to be turned off when the voltage of the capacitor reaches the maximum working voltage of the chip, so that the capacitor supplies power to the protected circuit inside the chip.

[0023] Optionally, the control signal output to the first switch module according to the parameters of the capacitor and the parameters of the protected circuit comprises:

[0024] The charging time and discharging time of the capacitor are calculated according to the parameters of the capacitor and the parameters of the protected circuit, and the control signal is output to the first switch module according to the charging time and the discharging time.

[0025] The technical effect of the embodiment of the present application is that: the technical solution controls the power supply switching of the external power supply and the energy storage module, and synchronously controls the start and stop of the clock signal, so that the protected circuit only runs in the state of being isolated from the external power supply and being powered by the energy storage module, thereby effectively cutting off the side channel leakage paths such as power consumption, electromagnetic and timing, realizing the hardware-level protection against side channel attacks, significantly improving the security and anti-analysis capability of the protected circuit, and further making the electromagnetic analysis lack data support to fundamentally isolate the way of side channel attacks. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0027] Figure 1 is a first structural schematic diagram of a power supply isolation device for preventing side channel attacks provided by the first embodiment of the present application;

[0028] Figure 2 is a structural schematic diagram of a clock gating module in the power supply isolation device for preventing side channel attacks provided by the first embodiment of the present application;

[0029] Figure 3 is a waveform diagram of the input signal and the output signal of the clock gating module in the power supply isolation device for preventing side channel attacks provided by the first embodiment of the present application;

[0030] Figure 4 is a third structural schematic diagram of a power supply isolation device for preventing side channel attacks provided by the first embodiment of the present application;

[0031] Figure 5 is a circuit diagram of a power supply isolation device for preventing side channel attacks provided by the first embodiment of the present application;

[0032] In the figure: 101, first energy storage module; 102, protected circuit; 103, first switch module; 104, external power supply; 105, clock gating module; 106, control module; 108, second switch module; 111, NOT gate; 112, AND gate. DETAILED DESCRIPTION

[0033] With reference to the drawings and the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present application.

[0034] It should be understood that the present application can be implemented in various forms and should not be interpreted as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that the disclosure will be thorough and complete and will fully convey the scope of the application to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions can be exaggerated for clarity. Like reference numerals in the drawings denote like elements throughout.

[0035] It should be understood that when an element or layer is referred to as being "on", "adjacent", "connected to", or "coupled to" another element or layer, it can be directly on, adjacent, connected or coupled to the other element or layer, or one or more intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on", "directly adjacent", "directly connected to", or "directly coupled to" another element or layer, then there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0036] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] For a thorough understanding of the present application, detailed descriptions of the structure and steps will be presented in the following description with reference to the accompanying drawings. In addition to the detailed description, the preferred embodiments of the present application are described as follows.

[0038] Embodiment One

[0039] The embodiment one provides a power isolation device for preventing side channel attack, as shown in the accompanying drawings, comprising: Figure 1

[0040] A first energy storage module 101 is configured to store and release electric energy to a protected circuit 102;

[0041] A first switch module 103 is connected to an external power supply 104 at one end, and connected to the first energy storage module 101 and the protected circuit 102 at the other end, and configured to supply or stop supplying electric energy to the first energy storage module 101 and the protected circuit 102 according to a control signal;

[0042] A clock gating module 105 is connected to the protected circuit 102, and configured to provide or not provide a working clock signal to the protected circuit 102 according to a control signal;

[0043] A control module 106 is connected to the first switch module 103 and the clock gating module 105, and configured to output control signals to the first switch module 103 and the clock gating module 105 respectively, so as to control the clock gating module 105 to stop outputting the working clock signal and make the protected circuit 102 stop working when the external power supply 104 is supplying electric energy, and control the clock gating module 105 to output the working clock signal and make the protected circuit 102 in a working state when the external power supply 104 stops supplying electric energy and the first energy storage module 101 supplies electric energy to the protected circuit.

[0044] ​The first energy storage module 101 is used for storing electric energy, for example, through a chip internal capacitor or other energy storage technology; the protected circuit is usually a small-scale encryption and decryption circuit in the chip; when the external power supply 104 is disconnected, the stored electric energy is released to the protected circuit 102, maintaining the continuous power supply to the protected circuit 102; the first energy storage module 101 disconnects the power supply path of the external power supply 104, realizes electrical isolation with the external power supply system, and thus cuts off the attack channel of using the power supply line in side channel attacks. The control module 106 outputs a control signal according to the parameters required for charging and discharging of the capacitor, which are calculated in advance according to the objective conditions such as the capacity of the capacitor and the working voltage of the protected circuit; the first switch module 103 controls its on-off state according to the signal of the control module 106, realizing the following two working modes: power supply mode: allowing the external power supply 104 to charge the first energy storage module 101 and the protected circuit 102; isolation mode: cutting off the power supply of the external power supply 104, avoiding the synchronization of external power supply behavior and encryption and decryption operation, and thus preventing electromagnetic or power consumption attacks; disconnecting the path of the external power supply 104 through logic control, avoiding the attacker from inferring the circuit behavior by detecting the power line fluctuation, and thus enhancing the anti-side channel attack capability. The clock gating module 105 receives the signal of the control module 106 and conditionally provides a clock signal to the protected circuit 102; when the clock signal output is prohibited, the protected circuit 102 enters a pause or sleep state; after the power supply is switched to the first energy storage module 101, the clock signal is re-enabled, and the protected circuit 102 resumes work; by dynamically controlling the working clock, sensitive operations during the external power supply 104 power supply period are avoided, effectively preventing the attacker from implementing side channel attacks through timing, power consumption synchronization and other methods. The control module 106 is the core control logic module, generates and sends a control signal, controls the first switch module 103 to connect or disconnect the external power supply 104; controls the clock gating module 105 to control whether the circuit is running; realizes the coupling and cooperation of power supply control and timing control, so that the external power supply and the protected circuit running are mutually exclusive.

[0045] The embodiment includes the following working stages:

[0046] Charging and sleep stage (external power supply 104 is connected): the control module 106 controls the first switch module 103 to conduct, so that the external power supply 104 supplies power to the first energy storage module 101 and the protected circuit 102; at the same time, the control module 106 controls the clock gating module 105 to close, and does not provide a clock signal to the protected circuit 102; at this time, the protected circuit 102 stops working, thereby avoiding the leakage of power consumption characteristic information in the power supply state.

[0047] Isolation and running stage (external power supply 104 is disconnected): the control module 106 controls the first switch module 103 to disconnect, so that the external power supply 104 is completely isolated from the internal system; the first energy storage module 101 supplies power to the protected circuit 102; the control module 106 controls the clock gating module 105 to open, and provides a clock signal to the protected circuit 102; at this time, the protected circuit 102 starts to run, such as performing encryption and decryption and other sensitive operations; since the external power supply has been disconnected, the attacker cannot obtain side channel information such as current and voltage fluctuation through the external power supply 104 line, effectively preventing differential power analysis, timing analysis and other attacks.

[0048] The technical effect of the technical solution provided by the embodiment one is that: by setting the first energy storage module, the first switch module, the clock gating module and the control module, a controllable power supply and clock isolation mechanism is constructed, and the protected circuit is prohibited from running during external power supply; only in the isolated state of the disconnected external power supply and the power supply by the energy storage module, the protected circuit is allowed to run, thereby achieving the following technical effects: during the key operation (such as encryption and decryption), the external power supply is disconnected by controlling the first switch module, and the protected circuit is only powered by the internal energy storage module, and the external power supply cannot monitor the current and power consumption changes, effectively preventing side channel attacks such as power analysis (DPA) and electromagnetic analysis (EMA); during the external power supply, the control module closes the clock gating module, and the protected circuit is prohibited from receiving the working clock signal, so as to ensure that the circuit is in a static state and avoid the leakage of running timing information; by controlling the clock signal and the power supply on-off through the control module, an unpredictable and external feature-free running window is constructed, avoiding the disadvantages of the traditional disturbance mechanism which is easy to be identified and modeled; only in the necessary isolated state, the protected circuit is run, avoiding the power waste caused by invalid running and continuous disturbance, and achieving the balance between security and energy efficiency.

[0049] In summary, the technical solution controls the power supply switching of the external power supply and the energy storage module, and synchronously controls the start and stop of the clock signal, so that the protected circuit only runs in the state of being isolated from the external power supply and being powered by the energy storage module, thereby effectively cutting off the side channel leakage paths of current, power consumption, electromagnetic and timing, realizing the hardware-level protection against side channel attacks, and significantly improving the security and analysis resistance of the protected circuit.

[0050] As an implementation manner, the second input end of the clock gating module 105 receives an external clock signal, and the first input end receives a control signal, for outputting a working clock signal when the control signal is in a first level state, and stopping outputting the working clock signal when the control signal is in a second level state.

[0051] The clock gating module 105 switches functions according to the level state of the control signal as follows: when the control signal is in a first level state (e.g., low), the clock gating module 105 is turned on to allow the external clock signal to pass through the output end thereof, to provide a normal working clock signal to the protected circuit 102, so that the protected circuit 102 enters a running state. When the control signal is in a second level state (e.g., high), the clock gating module 105 is turned off to block the transmission of the external clock signal, so that the protected circuit 102 cannot obtain the clock signal and thus is in a non-working or suspended state.

[0052] The technical effect of the embodiment is that the clock gating module 105 selectively outputs or shields the external clock signal according to the level state of the control signal, to realize accurate control of the running state of the protected circuit, to prohibit the circuit from working in a non-isolated state, to prevent timing information from being leaked, and thus to effectively improve the protection capability of the system against clock analysis attacks in side-channel attacks.

[0053] As an example, as shown in Figure 2 The clock gating module 105 includes a NOT gate 111 and an AND gate 112. The first input end of the AND gate 112 is the first input end of the clock gating module 105, the input end of the NOT gate 111 is the second input end of the clock gating module 105, the output end of the NOT gate 111 is connected to the second input end of the AND gate 112, and the output end of the AND gate 112 is the output end of the clock gating module 105.

[0054] As shown in Figure 3 When the control signal con is in the first level state (e.g., low), the NOT gate 111 outputs a high level, and if the external clock signal clock1 exists, the AND gate 112 transmits the clock signal clock2 to the output end, to allow the protected circuit 102 to normally receive the clock signal clock2 and run. When the control signal is in the second level state (e.g., high), the NOT gate 111 outputs a low level, and regardless of the external clock signal clock1, the output of the AND gate 112 is always low, to block the transmission of the clock signal, so that the protected circuit 102 stops running.

[0055] The specific working process is as follows:

[0056] When the control signal con is high, the first switch module 103 is closed to be powered on, and the external power supply 104 charges the first energy storage module 101. At this time, the clock gating module 105 turns off the working clock, and the protected circuit 102 does not work.

[0057] When the control signal con is low, the first switch module 103 is disconnected, and the first energy storage module 101 is discharged to serve as an internal power supply of the protected circuit 102. At this time, the clock gating module 105 turns on the working clock, and the protected circuit 102 normally works.

[0058] The technical effect of the embodiment is that through the logical combination, the output of the external clock signal can be effectively controlled based on the control signal, so as to realize accurate control and dynamic switching of the working state of the protected circuit 102 in the power isolation device, and further prevent the side channel attack from using the working timing to speculate the key data, and effectively improve the security of the system.

[0059] As an embodiment, as shown in Figure 4 The power isolation device further comprises:

[0060] The second switch module 108 has one end connected to the first energy storage module 101, and the other end grounded, and the control end of the second switch module 108 is connected to the control module 106.

[0061] When the control module 106 controls the first switch module 103 and the second switch module 108 to be conductive, the external power supply 104, the first switch module 103, the first energy storage module 101 and the second switch module 108 form a first power supply loop.

[0062] When the control module 106 controls the first switch module 103 and the second switch module 108 to be non-conductive, the first energy storage module 101 forms a second power supply loop.

[0063] To further improve the security and stability of the power supply switching process, the power isolation device further comprises a second switch module 108, and based on the control state of the first switch module 103 and the second switch module 108, two different power supply loop structures are formed.

[0064] When the control module 106 sends a control signal, the second switch module 108 is conductive, providing a stable grounding path for the energy storage module and forming a complete power supply loop; when the control module 106 controls the second switch module 108 to be non-conductive, the loop is cut off; which can be used to control the discharge path, form the power supply switching logic, and enhance the power supply security of the system; the second switch module 108 can be realized by using low-side MOSFET, solid-state relay and other switching devices. The control module 106 controls the conductive / non-conductive state of the first switch module 103 and the second switch module 108, realizes two different working modes and power supply structures; the control module 106 controls the first switch module 103 to be conductive, connecting the external power supply 104; controls the second switch module 108 to be conductive to provide a ground loop; forms a first power supply path:

[0065] External power supply 104→first switch module 103→first energy storage module 101+→second switch module 108→ground. The external power supply 104 charges the two energy storage modules at the same time; the two energy storage modules pre-store electric energy, preparing for subsequent isolated operation; this stage usually does not start the protected circuit 102 to run.

[0066] The control module 106 controls the first switch module 103 to turn off, disconnecting the external power supply 104; controls the second switch module 108 to turn off, forming a power supply path:

[0067] First energy storage module 101→protected circuit 102 (internal power supply loop).

[0068] The energy charged in the early stage is jointly provided by the energy storage module to provide working power; the external power supply 104 is completely disconnected, and the system is in an electrically isolated state; in this mode, the control module 106 can simultaneously open the clock gate module 105, so that the protected circuit 102 starts to perform sensitive operations (such as encryption and decryption); prevent side channel attacks from obtaining sensitive information through the power supply path.

[0069] The technical effect of the embodiment is that by setting the second switch module 108, and combining the first switch module 103 and the first energy storage module 101, a switchable first power supply loop and a second power supply loop are constructed, realizing dynamic switching and closed-loop control between external power supply and isolated operation of the system. The structure can ensure that the multi-stage energy storage is completed when the external power supply 104 supplies power, and the energy storage module continues to supply power after the external power supply 104 is disconnected, ensuring the continuity and isolation of the power supply of the protected circuit 102, and effectively improving the anti-interference ability and the ability to resist side channel attacks of the system.

[0070] As an implementation mode, the first energy storage module 101 is a capacitor arranged inside the chip, and the control module 106 is further configured to output a control signal to the first switch module according to parameters of the capacitor and parameters of the protected circuit, so that the voltage of the capacitor is controlled to be charged by the first switch module 103 before reaching the minimum value of the working voltage of the chip, and the voltage of the capacitor is controlled to be turned off by the first switch module 103 when reaching the maximum value of the working voltage of the chip, so that the capacitor supplies power to the protected circuit inside the chip.

[0071] The first energy storage module 101 is a capacitor, which is used to store energy in the power supply stage of the external power supply 104 and release energy when the external power supply 104 is disconnected, and supply power to the protected circuit 102. The voltage state of the capacitor directly reflects its energy storage capacity, and the higher the voltage, the more sufficient the energy storage. The control module 106 collects the terminal voltage of the first energy storage module 101 in real time; according to the preset upper limit (maximum value) and lower limit (minimum value) of the voltage, the on-off state of the first switch module 103 is controlled to realize closed-loop control of the capacitor charging process. The control logic is as follows: when the voltage of the capacitor is about to reach the minimum value of the working voltage of the chip, the control module 106 outputs a control signal to make the first switch module 103 conductive; the external power supply 104 starts to charge the capacitor to prevent the low energy storage from affecting the subsequent isolated power supply. When the voltage of the capacitor reaches the maximum value of the working voltage of the chip, the control module 106 outputs a control signal to make the first switch module 103 off; the charging is terminated to prevent overcharging of the capacitor, protect the elements, and reduce energy loss, and the capacitor supplies power to the protected circuit in the chip.

[0072] The technical effect of the embodiment is that the control module 106 dynamically controls the on-off of the first switch module 103 according to the voltage state of the capacitor in the first energy storage module 101, so that the capacitor is turned on in time before the voltage reaches the minimum value and turned off in time when the voltage reaches the maximum value, avoiding overcharging or under-voltage, and ensuring that the capacitor is in a safe and stable working voltage range; this mechanism not only improves the energy storage efficiency, but also ensures that there is enough power supply during the isolation operation, effectively enhances the power supply stability and operation reliability of the system, and prevents the normal operation of the protected circuit 102 from being affected by insufficient or overcharged capacitor energy.

[0073] As an embodiment, the control module 106 calculates the charging time and discharging time of the capacitor according to the parameters of the capacitor and the parameters of the protected circuit, and outputs a control signal to the first switch module according to the charging time and discharging time.

[0074] The parameters of the capacitor can be the upper limit voltage Vmax, the lower limit voltage Vmin, and the capacity of the capacitor; the parameters of the protected circuit 102 can be the resistance and working current of the protected circuit, and the control module 106 calculates the charging time and discharging time according to the above parameters according to a preset formula. When the calculated charging time is reached, the control module 106 outputs an off signal (stops charging) to the first switch module to ensure that the voltage does not exceed the upper limit voltage Vmax. Before the calculated discharging time is reached, the control module 106 outputs an on signal (starts charging) in advance to ensure that the voltage does not drop below Vmin.

[0075] As an example, as Figure 5As shown, Vdd and Vss represent the positive and negative terminals of the external power supply 104; switches K1 and K2 represent the chip internal control power supply switches; when the control signal con is high, the external power supply 104 is powered; when the control signal con is low, the large capacitor C is powered. The control signal con is a control signal for controlling the external power supply 104 switch and charging and discharging the large capacitor C; the large capacitor C can be realized by a metal-insulator-metal capacitor or a metal-oxide-metal capacitor formed by the chip metal layer.

[0076] As an embodiment, the capacitor is integrated in the chip inside the protected circuit 102, and the capacitor is a metal-insulator-metal capacitor or a metal-oxide-metal capacitor.

[0077] In this embodiment, the capacitor is integrated in the chip inside the protected circuit 102, that is, an on-chip energy storage structure is formed. The capacitor can adopt an on-chip integrated metal-insulator-metal (MIM) capacitor, a metal-oxide-metal (MOM) capacitor, or other process realizable high-density capacitor structures; one end of the capacitor is connected to the output end of the first switch module 103 through the internal interconnection line of the chip, for receiving the external power supply 104 power supply and completing the charge storage when the first switch module 103 is turned on; the other end of the capacitor is connected to the second switch module 108, and when the first switch module 103 is disconnected and the second switch module 108 is disconnected, the capacitor releases the electric energy and supplies power to the protected circuit 102.

[0078] By integrating the capacitor in the chip inside the protected circuit 102, an on-chip energy storage structure is formed, which not only improves the system integration and power supply response speed, but also avoids the power consumption leakage risk caused by external wiring. By using high-density integration processes such as MIM capacitors or MOM capacitors, effective energy storage can be realized in a limited chip area, providing isolated power supply for the protected circuit 102 after the external power supply 104 is disconnected, significantly enhancing the system's resistance to side-channel attacks and power supply security.

[0079] As an example, taking the 28nm process working voltage as an example, Vmin=0.8v, Vmax=1.0v, and the standard working voltage is 0.9v; to realize a MOM capacitor with a capacity of C=2nf, the chip metal layer area needs to be 1mm 2 At this time, the resistance of the protected circuit is approximately R=100Ω, and it is assumed that the working current of the protected circuit is I=8mA; the charging time calculation formula is as follows:

[0080] The voltage Vc of the capacitor is Vmax(1-e -t / RC );

[0081] Here, because Vmax=1.0v, Vmin=0.8v, and t 充=4RC, which can ensure that the charging is completed from 80% to 99%, t 充 =4RC=4x100x2x10 -9 =8x10 -7 s=800ns. As the charging time satisfies the following formula:

[0082] t=RC;e -1 =36.8%;1-e -t / RC =63.2%Vmax;

[0083] t=2.3RC;e -2.3 =10%;1-e -t / RC =90%Vmax

[0084] t=3RC;e -3 =5%;1-e -t / RC =95%Vmax;

[0085] t=5RC;e -5 =1%;1-e -t / RC =99%Vmax.

[0086] The discharge time calculation formula is:

[0087] C=(Vmax+Vmin)xIxt / (Vmax^2-Vmin^2);

[0088] The capacitor discharge time formula is derived as follows:

[0089] t 放 =(2x10 -9 x(1 2 -0.8 2 )) / ((1+0.8)x8x10 -3 )=50x10 -9 s=50ns

[0090] The charging time in the control signal is 800ns and the discharge time is 50ns.

[0091] Embodiment Two

[0092] The embodiment two provides an isolation method of the power supply isolation device for preventing side channel attack provided in the embodiment one, and the isolation method comprises the following steps:

[0093] The control signal is output to the first switch module and the clock gating module respectively, so that the clock gating module stops outputting the working clock signal and the protected circuit stops working in the case of external power supply, and the clock gating module outputs the working clock signal and the protected circuit is in the working state in the case of external power supply stopping and the first energy storage module supplying power to the protected circuit.

[0094] Further, the first energy storage module is a capacitor arranged inside the chip;

[0095] The isolation method further comprises:

[0096] According to the parameters of the capacitor and the parameters of the protected circuit, a control signal is output to the first switch module, so that the voltage of the capacitor is controlled to turn on the first switch module to charge the capacitor before reaching the minimum value of the working voltage of the chip, and the voltage of the capacitor is controlled to turn off the first switch module when reaching the maximum value of the working voltage of the chip, so that the capacitor supplies power to the protected circuit inside the chip.

[0097] Further, according to the parameters of the capacitor and the parameters of the protected circuit, the control signal is output to the first switch module, comprising:

[0098] According to the parameters of the capacitor and the parameters of the protected circuit, the charging time and the discharging time of the capacitor are calculated, and the control signal is output to the first switch module according to the charging time and the discharging time.

[0099] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent ones; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A power isolation device for protection against side-channel attacks, characterized in that, The power supply isolation device comprises: a first energy storage module for storing and releasing electric energy to a protected circuit; a first switch module having one end connected to an external power supply and the other end connected to the first energy storage module and the protected circuit respectively, for enabling or disabling the external power supply to supply power to the first energy storage module and the protected circuit according to a control signal; a clock gating module connected to the protected circuit, for providing or not providing a working clock signal to the protected circuit according to the control signal; a control module connected to the first switch module and the clock gating module respectively, for outputting a control signal to the first switch module and the clock gating module respectively, so as to control the clock gating module to stop outputting the working clock signal and make the protected circuit stop working when the external power supply is powered, and control the clock gating module to output the working clock signal and make the protected circuit in a working state when the external power supply is disabled and the first energy storage module supplies power to the protected circuit; a second input end of the clock gating module receives an external clock signal, and a first input end of the clock gating module receives the control signal, for outputting the working clock signal when the control signal is in a first level state, and stopping outputting the working clock signal when the control signal is in a second level state; the clock gating module comprises a NOT gate and an AND gate, a first input end of the AND gate is the first input end of the clock gating module, an input end of the NOT gate is the second input end of the clock gating module, an output end of the NOT gate is connected to a second input end of the AND gate, and an output end of the AND gate is the output end of the clock gating module.

2. The power isolation device of claim 1, wherein, The power supply isolation device further comprises: a second switch module having one end connected to the first energy storage module and the other end grounded, and a control end connected to the control module; when the control module controls the first switch module and the second switch module to be both turned on, the external power supply, the first switch module, the first energy storage module and the second switch module form a first power supply loop; when the control module controls the first switch module and the second switch module to be both turned off, the first energy storage module forms a second power supply loop.

3. The power isolation device of claim 1, wherein, The first energy storage module is a capacitor arranged inside a chip, and the control module is further configured to output a control signal to the first switch module according to parameters of the capacitor and parameters of the protected circuit, so as to control the first switch module to be turned on to charge the capacitor before the voltage of the capacitor reaches a minimum working voltage of the chip, and control the first switch module to be turned off when the voltage of the capacitor reaches a maximum working voltage of the chip, so as to make the capacitor supply power to the protected circuit inside the chip.

4. The power isolation device of claim 3, wherein, The control module calculates charging time and discharging time of the capacitor according to the parameters of the capacitor and the parameters of the protected circuit, and outputs a control signal to the first switch module according to the charging time and the discharging time.

5. The power isolation device of claim 3, wherein, The capacitor is integrated inside a chip of the protected circuit, and the capacitor is a metal-insulator-metal capacitor or a metal-oxide-metal capacitor.

6. An isolation method based on the power isolation device for preventing side-channel attacks according to claim 1, characterized in that, The isolation method comprises: The control signal is output to the first switch module and the clock gating module respectively, so that the clock gating module stops outputting a working clock signal to control the protected circuit to stop working when the external power supply is powered, and the clock gating module outputs the working clock signal to control the protected circuit to be in a working state when the external power supply stops supplying power and the first energy storage module supplies power to the protected circuit.

7. The method of claim 6, wherein, The first energy storage module is a capacitor arranged inside a chip; The isolation method further comprises: The control signal is output to the first switch module according to parameters of the capacitor and parameters of the protected circuit, so that the voltage of the capacitor controls the first switch module to be turned on to charge the capacitor before the voltage reaches a minimum working voltage of the chip, and the voltage of the capacitor controls the first switch module to be turned off when the voltage reaches a maximum working voltage of the chip, so that the capacitor supplies power to the protected circuit inside the chip.

8. The method of claim 7, wherein, The control signal output to the first switch module according to the parameters of the capacitor and the parameters of the protected circuit comprises: The charging time and the discharging time of the capacitor are calculated according to the parameters of the capacitor and the parameters of the protected circuit, and the control signal is output to the first switch module according to the charging time and the discharging time.

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