阅读说明：本技术 电压攻击检测电路和芯片 (Voltage attack detection circuit and chip ) 是由 杨江 薛建锋 于 2020-04-01 设计创作，主要内容包括：提供一种电压攻击检测电路和芯片。所述电压攻击检测电路包括至少一个电压调节电路、至少一个电压传感器和至少一个毛刺传感器；所述至少一个电压传感器分别用于接收所述至少一个电压调节电路输出的至少一个第一电压并分别用于输出至少一个第一信号,所述至少一个第一信号分别用于指示是否受到攻击时长位于第一范围内且攻击力度位于第二范围内的电压攻击,所述至少一个毛刺传感器分别用于接收所述至少一个第一电压并分别用于输出至少一个第二信号,所述至少一个第二信号分别用于指示是否受到攻击时长位于第三范围内且攻击力度位于第四范围内的电压攻击。所述电压攻击检测电路不仅能够针对全电源域进行电压攻击防护,而且能够提高防护方案的可靠性。(A voltage attack detection circuit and a chip are provided. The voltage attack detection circuit comprises at least one voltage regulation circuit, at least one voltage sensor and at least one glitch sensor; the at least one voltage sensor is respectively used for receiving at least one first voltage output by the at least one voltage regulating circuit and respectively used for outputting at least one first signal, the at least one first signal is respectively used for indicating whether the voltage attack with attack duration in a first range and attack strength in a second range is received, the at least one glitch sensor is respectively used for receiving the at least one first voltage and respectively used for outputting at least one second signal, and the at least one second signal is respectively used for indicating whether the voltage attack with attack duration in a third range and attack strength in a fourth range is received. The voltage attack detection circuit can not only protect against voltage attack in a full power domain, but also improve the reliability of the protection scheme.)

1. A voltage attack detection circuit, comprising:

at least one voltage regulation circuit;

the at least one voltage regulating circuit is connected to an external power supply, the at least one voltage regulating circuit is respectively used for converting the external power supply into at least one internal power supply, and the at least one internal power supply is respectively used for outputting at least one first voltage;

at least one voltage sensor and at least one glitch sensor;

wherein the at least one voltage sensor is respectively configured to receive the at least one first voltage and respectively configured to output at least one first signal, the at least one first signal is respectively used for indicating whether the at least one internal power supply is attacked by voltages with attack duration in a first range and attack strength in a second range, the at least one glitch sensor is configured to receive the at least one first voltage and to output at least one second signal, the at least one second signal is respectively used for indicating whether the at least one internal power supply is attacked by the voltage with the attack duration being in the third range and the attack strength being in the fourth range, the minimum value of the first range is greater than or equal to the maximum value of the third range, and the absolute value of the maximum value of the second range is less than or equal to the absolute value of any value of the fourth range.

2. The voltage attack detection circuit of claim 1 wherein the first range has a minimum value of 0.1 us.

3. The voltage attack detection circuit of claim 1 or 2 wherein the third range is 1 ns-0.1 us.

4. The voltage attack detection circuit according to any one of claims 1 to 3, wherein an absolute value of a maximum value of the second range and/or an absolute value of a minimum value of the fourth range is proportional to an absolute value of the voltage of the external power supply.

5. The voltage attack detection circuit of claim 4 wherein the second range is-0.5V, where V represents a voltage value of the external power source.

6. The voltage attack detection circuit according to claim 4, wherein the fourth range is 0.5V-V, and/or the fourth range is-V-0.5V.

7. The voltage attack detection circuit according to any one of claims 1 to 6, wherein the at least one voltage sensor is respectively connected to the at least one internal power supply to respectively receive the at least one first voltage, the at least one voltage sensor being configured to output the at least one first signal based on the received reference voltage and the at least one first voltage.

8. The voltage attack detection circuit according to any one of claims 1 to 7, further comprising:

an external power supply voltage sensor and an external power supply glitch sensor;

the external power supply is used for outputting a second voltage, the external power supply voltage sensor is connected to the external power supply, the external power supply voltage sensor is used for receiving the second voltage and outputting a third signal, and the third signal is used for indicating whether the second voltage is attacked by voltages of which attack duration is within the first range and attack strength is within the second range; the external power supply burr sensor is connected to the external power supply, the external power supply burr sensor is used for receiving the second voltage and outputting a fourth signal, and the third signal is used for indicating whether the second voltage is attacked or not, wherein the attack duration is within the third range and the attack strength is within the fourth range.

9. The voltage attack detection circuit according to any one of claims 1 to 8 wherein each of the at least one voltage regulation circuit comprises at least one of: the low-dropout linear regulator comprises a low-dropout linear regulator, a charge pump, a step-down change circuit, a step-up change circuit and a bidirectional direct current converter.

10. The voltage attack detection circuit according to any one of claims 1 to 9 wherein each of the at least one voltage sensors includes a hysteresis comparator.

11. A chip, comprising:

a power management unit; and

the voltage attack detection circuit according to any one of claims 1 to 10;

the power management unit is connected to the voltage attack detection circuit, and the voltage attack detection circuit is used for detecting whether the power voltage of the power management unit is attacked by voltage.

Technical Field

Embodiments of the present application relate to the field of electronics, and more particularly, to a voltage attack detection circuit and a chip containing or equipped with the voltage attack detection circuit.

Background

With the widespread use of mobile payment and transactions, electronic devices are increasingly used to store, process, and transmit data containing critical information. For example, the security chip can be used to realize functions such as user identification and key data storage, and is widely applied to the financial field. The safety chip is used as the basis of safety hardware and plays an important role in information safety. In recent years, more and more chip level attack methods and examples are disclosed, and accordingly, higher and higher requirements are put on chip level security.

There are a number of attack approaches at the chip level, with error injection attacks being the most effective. The purpose of the fault injection attack is to force the chip to perform an abnormal operation, thereby exposing the secure information in the chip. At this time, an attacker can easily acquire confidential data in the security chip by using a failure analysis technology. The attack of the fault injection can be performed in various ways, such as voltage attack, temperature attack, laser attack, electromagnetic attack, and the like.

Aiming at voltage attack, the power supply voltage of a chip power domain is changed, so that the circuit inside the chip is abnormal in operation, the trigger enters an error state, and the processor skips or executes error operation, so that the safety information in the chip is exposed.

Usually, the inside of a chip is divided into a plurality of different power domains, each power domain is independent, but there is a certain dependence and interaction, so each power domain must be protected. In other words, a complete set of voltage attack protection scheme aiming at the full power domain is constructed by the chip; in addition, the existing anti-attack scheme of the voltage only aims at the protection of the voltage to be detected, the protection form is single, and a certain protection blind area exists.

Therefore, it is important to provide a complete and reliable protection scheme against power source attacks.

Disclosure of Invention

Provided are a voltage attack detection circuit and a chip, which can not only protect against voltage attacks in a full power domain, but also improve the reliability of a protection scheme.

In a first aspect, a voltage attack detection circuit is provided, including:

at least one voltage regulation circuit;

the at least one voltage regulating circuit is connected to an external power supply, the at least one voltage regulating circuit is respectively used for converting the external power supply into at least one internal power supply, and the at least one internal power supply is respectively used for outputting at least one first voltage;

at least one voltage sensor and at least one glitch sensor;

wherein the at least one voltage sensor is respectively configured to receive the at least one first voltage and respectively configured to output at least one first signal, the at least one first signal is respectively used for indicating whether the at least one internal power supply is attacked by voltages with attack duration in a first range and attack strength in a second range, the at least one glitch sensor is configured to receive the at least one first voltage and to output at least one second signal, the at least one second signal is respectively used for indicating whether the at least one internal power supply is attacked by the voltage with the attack duration being in the third range and the attack strength being in the fourth range, the minimum value of the first range is greater than or equal to the maximum value of the third range, and the absolute value of the maximum value of the second range is less than or equal to the absolute value of any value of the fourth range.

Through at least one voltage sensor, can detect out the voltage attack that attack duration is located first scope and attack dynamics is located the second scope, through at least one burr sensor, can detect out the voltage attack that attack duration is located the third scope and attack dynamics is located the fourth scope, from attack duration and attack dynamics, can omnidirectional voltage attack protection to improve the reliability of the protection scheme of voltage attack.

In other words, the voltage attack types are distinguished by determining the characteristics of the voltage attack (namely attack duration and attack strength), and then different protection measures (namely, a voltage sensor and a burr sensor) are adopted for different voltage attack types to carry out voltage attack protection, so that the attack means aiming at each power domain (namely, each voltage regulating circuit) is covered in all directions, and a comprehensive and reliable anti-attack scheme of the full power domain (namely, the at least one voltage regulating circuit) is constructed.

In some possible implementations, the minimum value of the first range is 0.1 us.

In some possible implementations, the third range is 1ns to 0.1 us.

In some possible implementations, an absolute value of a maximum value of the second range and/or an absolute value of a minimum value of the fourth range is proportional to an absolute value of the voltage of the external power source.

In some possible implementations, the second range is-0.5V to 0.5V, where V represents a voltage value of the external power source.

In some possible implementations, the fourth range is 0.5V to V, and/or the fourth range is-V to-0.5V.

In some possible implementations, the at least one voltage sensor is respectively connected to the at least one internal power supply to respectively receive the at least one first voltage, and the at least one voltage sensor is configured to output the at least one first signal based on the received reference voltage and the at least one first voltage.

In some possible implementations, the voltage attack detection circuit further includes:

an external power supply voltage sensor and an external power supply glitch sensor;

the external power supply is used for outputting a second voltage, the external power supply voltage sensor is connected to the external power supply, the external power supply voltage sensor is used for receiving the second voltage and outputting a third signal, and the third signal is used for indicating whether the second voltage is attacked by voltages of which attack duration is within the first range and attack strength is within the second range; the external power supply burr sensor is connected to the external power supply, the external power supply burr sensor is used for receiving the second voltage and outputting a fourth signal, and the third signal is used for indicating whether the second voltage is attacked or not, wherein the attack duration is within the third range and the attack strength is within the fourth range.

In some possible implementations, each of the at least one voltage regulating circuit includes at least one of the following elements: the low-dropout linear regulator comprises a low-dropout linear regulator, a charge pump, a step-down change circuit, a step-up change circuit and a bidirectional direct current converter.

In some possible implementations, each of the at least one voltage sensor includes a hysteresis comparator.

In a second aspect, a chip is provided, comprising:

a power management unit; and

the voltage attack detection circuit of the first aspect or any possible implementation manner of the first aspect; the power management unit is connected to the voltage attack detection circuit, and the voltage attack detection circuit is used for detecting whether the power voltage of the power management unit is attacked by voltage.

Drawings

Fig. 1 is a schematic diagram of a voltage attack type according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a positional relationship between the voltage sensor and the burr sensor and the voltage adjusting circuit according to the embodiment of the present application.

Fig. 3 is a schematic structural diagram of a voltage attack detection circuit according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of a voltage attack type according to an embodiment of the present application.

As shown in FIG. 1, two characteristics of voltage attack, namely attack strength V, are defined_{Attack of}And attack duration t_{Attack of}. Correspondingly, based on the characteristics of the voltage attack, the voltage attack is divided into a first class voltage attack and a second class voltage attack, wherein the first class voltage attack has V_{Attack of}Small and t_{Attack of}V of large, second class voltage attack_{Attack of}Large and t_{Attack of}Is small. For example, the first type of Voltage Attack may be a Supply Voltage Attack (Supply Voltage attach) and the second type of Voltage Attack may be a Glitch Attack (Glitch attach). The first class voltage attack and the second class voltage attack can enable the circuit inside the chip to work abnormally, so that the trigger enters an error state, the processor skips or executes error operation, and the safety information in the chip is exposed.

Based on the Voltage attack type, in the embodiment of the present application, a Voltage Sensor (Voltage Sensor) may be used for protection against the first type of Voltage attack, and a Glitch Sensor (Glitch Sensor) may be used for protection against the second type of Voltage attack.

The chip will have multiple power domains (i.e., internal power supplies). For example, the Input Voltage (Input Voltage) is converted into an Output Voltage (Output Voltage) by a Voltage regulator circuit (Voltage regulator), and power is supplied to other modules. When a plurality of such voltage regulating circuits are included in a chip, complex and various power domains are formed, and each power domain needs to be detected by a voltage sensor and a burr sensor to detect whether voltage attack is applied.

Fig. 2 is a schematic structural diagram of a positional relationship between the voltage sensor and the burr sensor and the voltage adjusting circuit according to the embodiment of the present application.

As shown in fig. 2, voltage attack detection circuit 100 may include a voltage regulation circuit 101, a first voltage sensor 102, a second voltage sensor 103, a first glitch sensor 104, and a second glitch sensor 105.

Wherein the first voltage sensor 102 and the first glitch sensor 104 are connected to an input of the voltage regulation circuit 101, and the second voltage sensor 103 and the second glitch sensor 105 are connected to an output of the voltage regulation circuit 101. Correspondingly, the first voltage sensor 102 and the second voltage sensor 103 are respectively configured to detect an input voltage and an output voltage of the voltage regulating circuit 101, so as to detect whether a power domain where the voltage regulating circuit 101 is located is under a voltage attack of a first voltage attack type. The first glitch sensor 104 and the second glitch sensor 105 are respectively configured to detect an input voltage and an output voltage of the voltage regulator circuit 101, so as to detect whether a power domain where the voltage regulator circuit 101 is located is under a voltage attack of a second voltage attack type.

Fig. 3 is a schematic structural diagram of a voltage attack detection circuit according to an embodiment of the present application.

As shown in fig. 3, the voltage attack detection circuit 200 may include at least one voltage regulation circuit; for example, the at least one voltage regulating circuit may include the first voltage regulating circuit 231, the second voltage regulating circuit 232, …, and the nth voltage regulating circuit 23N as shown in fig. 3. The at least one voltage regulating circuit is connected to an external power supply (VDD), and the at least one voltage regulating circuit is respectively used for converting the external power supply into at least one internal power supply; for example, the at least one internal power source may include internal power sources V1, V2, …, and VN shown in fig. 2, the at least one internal power source being respectively configured to output at least one first voltage for powering a certain module or modules within a chip. Optionally, the at least one first voltage may be partially equal, may also be all equal, and may also be different from each other, which is not specifically limited in this application embodiment.

Of course, in other alternative embodiments, the voltage attack detection circuit 200 may further include a plurality of external power sources, and in this case, each of the plurality of external power sources may be an external power source as shown in fig. 3. In other words, the plurality of external power sources may be respectively connected to a plurality of voltage regulation circuits, each of the plurality of voltage regulation circuits is configured to convert the external power source connected thereto into an internal power source, and the first voltage output by each of the plurality of voltage regulation circuits may be connected to one voltage sensor and one glitch sensor, so that the first voltage sensor and the first glitch sensor perform voltage attack detection, and accordingly, attack protection is performed in a full power source domain.

As shown in fig. 3, the voltage attack detection circuit 200 may further include at least one voltage sensor; for example, the voltage attack detection circuit 200 may further include a first voltage sensor 241, second voltage sensors 242, …, and an nth voltage sensor 24N as shown in fig. 3. The voltage attack detection circuit 200 may further include at least one glitch sensor; for example, the voltage attack detection circuit 200 may further include a first glitch sensor 251, second glitch sensors 252, …, and an nth glitch sensor 25N as shown in fig. 3. Wherein the at least one voltage sensor is respectively configured to receive the at least one first voltage and respectively configured to output at least one first signal, the at least one first signal is respectively used for indicating whether the at least one internal power supply is attacked by voltages with attack duration in a first range and attack strength in a second range, the at least one glitch sensor is configured to receive the at least one first voltage and to output at least one second signal, the at least one second signal is respectively used for indicating whether the at least one internal power supply is attacked by the voltage with the attack duration being in the third range and the attack strength being in the fourth range, the minimum value of the first range is greater than or equal to the maximum value of the third range, and the absolute value of the maximum value of the second range is less than or equal to the absolute value of any value of the fourth range.

Through at least one voltage sensor, can detect out the voltage attack that attack duration is located first scope and attack dynamics is located the second scope, through at least one burr sensor, can detect out the voltage attack that attack duration is located the third scope and attack dynamics is located the fourth scope, from attack duration and attack dynamics, can omnidirectional voltage attack protection to improve the reliability of the protection scheme of voltage attack.

In other words, the voltage attack types are distinguished by determining the characteristics of the voltage attack (namely attack duration and attack strength), and then different protection measures (namely, a voltage sensor and a burr sensor) are adopted for carrying out voltage attack protection aiming at different voltage attack types so as to comprehensively cover the attack means aiming at each power domain (namely, the output voltage of each voltage regulating circuit) to construct a comprehensive and reliable anti-attack scheme of the full power domain (namely, the at least one voltage regulating circuit).

The protection ranges of the voltage sensor and the burr sensor are described below with reference to table 1.

TABLE 1 protection Range of Voltage and Burr Sensors

As shown in table 1, in some embodiments of the present application, the first range has a minimum value of 0.1 microseconds (us). In other words, the first range is 0.1us ∞ to +∞. Wherein, V_attackMay be a DC voltage value, t_attackFor indicating the duration of the voltage. For example, the third range is 1 nanosecond (ns) to 0.1 microseconds (us). The second range is-0.5V to 0.5V, where V represents a voltage value of the external power supply. In other words, the fourth range is 0.5V to V, and/or the fourth range is-V to-0.5V.

It is understood that one skilled in the art may adjust any of the first, second, third and fourth ranges based on the actual situation. For example, when the glitch sensor is used to detect a voltage attack with a longer attack duration, the required resistance capacitance value is larger, and accordingly, the required layout area and power consumption are also larger, that is, when the glitch sensor is used to detect a voltage attack with a shorter attack duration, the required layout area and power consumption are smaller, and a person skilled in the art may adjust the third range and the fourth range based on actual configuration of the glitch sensor or actual requirements of the layout area and power consumption. Similarly, the skilled person may also adjust said first range and said second range depending on the actual configuration or actual requirements of the voltage sensor.

Similarly, the first range and the third range shown in table 1 are distinguished by 0.1us, and the second range and the fourth range are distinguished by ± 0.5 × V, which is only an example and is not specifically limited in the embodiment of the present application.

For example, the absolute value of the maximum value of the second range and/or the absolute value of the minimum value of the fourth range is proportional to the absolute value of the voltage of the external power source. For example, the absolute value of the maximum value of the second range and/or the absolute value of the minimum value of the fourth range may be a product of the absolute value of the voltage of the external power supply and a preset percentage. For example, the second range and the fourth range may be distinguished by 20% of the voltage of the external power source, i.e. the second range is-0.2V to 0.2V. The fourth range is 0.2V to V, and/or the fourth range is-V to-0.2V.

In some embodiments of the present application, the at least one voltage sensor is respectively connected to the at least one internal power supply to respectively receive the at least one first voltage, and the at least one voltage sensor is configured to output the at least one first signal based on the received reference voltage and the at least one first voltage.

For example, each of the at least one voltage sensor may be configured to output a first signal component based on the received first voltage and a received first reference signal, the first signal component indicating whether the received first voltage is greater than or equal to the first reference voltage; each of the at least one voltage sensor may be further configured to output a second signal component based on the received first voltage and the received second reference voltage, the second signal component may be configured to indicate whether the second voltage is less than or equal to the second reference voltage, and the first reference voltage is greater than the second reference voltage.

It should be appreciated that the glitch sensor in the embodiments of the present application can be any sensor that can be used to detect the second type of voltage attack. For example, the glitch sensor may comprise a latch sensor.

As shown in fig. 3, in some embodiments of the present application, the voltage attack detection circuit further includes:

an external power supply voltage sensor 210 and an external power supply glitch sensor 220;

wherein the external power supply is configured to output a second voltage, the external power supply voltage sensor 210 is connected to the external power supply, the external power supply voltage sensor 210 is configured to receive the second voltage and output a third signal, and the third signal is configured to indicate whether the second voltage is attacked by voltages with attack duration within the first range and attack strength within the second range; the external power supply glitch sensor 220 is connected to the external power supply, the external power supply glitch sensor 220 is used for receiving the second voltage and outputting a fourth signal, and the third signal is used for indicating whether the second voltage is attacked or not, wherein the attack duration is within the third range and the attack strength is within the fourth range.

In other words, a dedicated voltage sensor and burr sensor can be provided for the external power supply.

In some embodiments of the present application, each of the at least one voltage regulating circuit comprises at least one of the following elements:

low Dropout linear Regulator (LDO), a Charge Pump (Charge Pump), a BUCK converter (BUCK), a Boost converter (Boost), a bidirectional DC converter (DC-DC converter), and the like, which can provide a stable output voltage.

In some embodiments of the present application, each of the at least one voltage sensor comprises a hysteresis comparator.

It should be understood that fig. 1-3 are only examples of the present application and should not be construed as limiting the present application.

For example, in other embodiments, the voltage attack detection circuit 200 may further include a reference voltage generation circuit for generating a reference voltage, the reference voltage generation circuit being connected to the at least one voltage sensor and the at least one glitch sensor, respectively, such that each of the at least one voltage sensor outputs a first signal based on the received reference voltage and the received first voltage, and each of the at least one glitch sensor outputs a second signal based on the received reference voltage and the received first voltage.

For another example, in other embodiments, the voltage attack detection circuit 200 may further include a reference voltage detection circuit, connected to the reference voltage generation circuit, for detecting whether the reference voltage is abnormal, and further generating and outputting an indication signal to the at least one voltage sensor and the at least one glitch sensor. For example, when the indication signal indicates that the reference voltage is abnormal, even if the at least one first signal is respectively used for indicating that the at least one internal power supply is attacked by voltages with attack duration within a first range and attack strength within a second range, the at least one first signal is reset to indicate that the at least one internal power supply is not attacked by voltages.

For another example, in other embodiments, the voltage attack circuit 200 may further include a glitch signal detection circuit and the reference voltage generation circuit to eliminate glitches on the reference voltage, so as to improve the accuracy of the indication signal.

The application also provides a chip, which comprises a power management unit and the voltage attack detection circuit; the power management unit is connected to the voltage attack detection circuit, and the voltage attack detection circuit is used for detecting whether the power voltage of the power management unit is attacked by voltage.

In other words, the voltage attack detection circuit can be applied to any chip having a power management unit. Such as a security chip. For example, the security chip may be a fingerprint sensor chip or a processor chip or the like. The security chip is suitable for any electronic equipment. Such as portable or mobile computing devices, e.g., smart phones, laptops, tablets, gaming devices, etc., and other electronic devices, e.g., electronic databases, automobiles, Automated Teller Machines (ATMs), etc.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.