Device and method for defending power supply side channel attack of mobile equipment

Abstract

The invention belongs to the technical field of electric digital data processing, and relates to a device and a method for defending power supply side channel attack of mobile equipment. The method comprises the following steps: initializing a seed, and obtaining an initial random seed after a charger is inserted into a power supply; according to a random algorithm, module IDs and corresponding control signals are generated based on random seeds and used for identifying different dynamic resistance modules and controlling the dynamic resistance modules to be turned on or turned off; according to the generated module ID, a variable resistance module needing to be started is judged; the started variable resistance module dynamically adjusts the resistance value of an access circuit according to the control signal, so that intelligent adjustment of charging parameters is realized; and circularly executing the steps at a set rate until the charger is pulled out. According to the invention, by introducing the dynamic resistance module and a random seed-based signal generation method, the random disturbance of the current in the charging process is realized, the dynamic adjustment capability is strong, and the method can adapt to various charging devices and environments; and the charging efficiency and the safety are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electrical digital data processing, and relates to a device and method for defending against side channel attacks on power supply of mobile equipment. Background Art

[0002] With the widespread use of smartphones and mobile devices, device privacy protection faces increasingly complex security threats, among which power side channel attacks have gradually become an emerging privacy leakage channel. By modifying the charging device, attackers can collect voltage or current data during the charging process of the mobile device, analyze and identify the applications running on the device, and may even further infer the user's behavior habits or sensitive information.

[0003] The attack methods in the prior art mostly use the power side channel data to extract characteristic patterns, usually relying on the characteristic signals formed by the change of charging voltage or current. This technical means is simple to implement and highly concealed, but it also exposes the privacy data of the user's device, posing a serious security risk. As smart devices are frequently charged in daily use, the threat of power side channel attacks has become more prominent, and an efficient defense mechanism is urgently needed to protect user privacy and device data security. Summary of the invention

[0004] The purpose of the present invention is to provide a method and device for defending against side-channel attacks on the power supply of mobile devices based on hardware. During the charging process of the mobile device, the current is randomly disturbed to protect sensitive information and enhance the anti-attack capability of the device.

[0005] The technical solution provided by the present invention is: a device for defending against power side channel attacks on mobile devices, the device comprising: A control module, used to generate a random control signal to control the resistance value switched to the main circuit; N variable resistance modules, each of which can be connected to the main circuit and dynamically adjust its resistance value through control signals; The switching module is used to switch between multiple variable resistance modules. According to the module ID generated by the control module, the switching circuit determines which variable resistance module is connected to the main circuit.

[0006] Preferably, the variable resistance module is composed of a plurality of load resistors with different resistance values, and each load resistor is connected to the main circuit through a switching module.

[0007] Preferably, the switching module is composed of a plurality of MOSFETs.

[0008] The present invention also provides a method for defending against power side channel attacks on mobile devices, comprising the following steps: Step S1, initializing the seed, after the charger is plugged into a power source, obtaining the initial random seed; Step S2: Generate module ID and corresponding control signal based on random seed according to random algorithm, so as to identify different dynamic resistance modules and control them to be turned on or off; Step S3, determining the variable resistance module to be started according to the generated module ID; Step S4, the started variable resistance module dynamically adjusts the resistance value of the circuit connected thereto according to the control signal, thereby realizing intelligent adjustment of the charging parameters; Step S5, looping through steps S2, S3 and S4 at a set rate until the charger is unplugged.

[0009] Preferably, step S2 is specifically as follows: using a random algorithm to generate a 9-bit binary pseudo-random number sequence as an initial control command; dividing the control command into two parts: taking the highest bit as the module ID to identify the variable resistor module currently in use; taking the remaining 8 bits as the control signal to control the dynamic adjustment of the resistance value in the variable resistor module.

[0010] The present invention realizes random disturbance of the current in the charging process by introducing a dynamic resistance module and a signal generation method based on random seeds. Compared with the traditional fixed resistance solution, the present invention has the following advantages: strong dynamic adjustment capability, adaptable to a variety of charging devices and environments; improved charging efficiency and safety; higher flexibility and scalability, easy to integrate into the existing charging system. Through the above technical solution, the present invention can effectively avoid the direct reading of the current signal of the target device by external devices, and improve the information security of mobile devices during the charging process. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of an operating scenario of a device for defending against power side channel attacks on mobile devices provided by an embodiment of the present invention; Figure 2 A schematic diagram of the structure of a device for defending against power side channel attacks on mobile devices provided by an embodiment of the present invention; Figure 3 A circuit block diagram of a device for defending against power side channel attacks on mobile devices provided by an embodiment of the present invention; Figure 4 A flow chart of a method for defending against power side channel attacks on mobile devices provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0012] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation examples: Example 1 Figure 1 Schematic diagram of the operating environment applicable to the embodiment of the present invention. Figure 1As shown, the defense device is connected between the mobile device 001 and the charging device 002. After the charging device 002 is plugged into a power source, the mobile device 001 starts charging and the defense device starts working at the same time.

[0013] Figure 2 The structure diagram of a device for defending against power side channel attacks on mobile devices applicable to an embodiment of the present invention is shown in FIG. Figure 4 The method provided in the illustrated embodiment specifically includes: The control module 100 is used to initialize the random seed, generate the module ID and the random control signal, and control the switching and dynamic adjustment of the variable resistance module 200; N variable resistance modules 200, used to dynamically adjust the resistance value of the access circuit according to the control signal to generate a random disturbance signal; The switching module 300 is used to switch between the plurality of variable resistance modules 200 and switch the variable resistance module to access the main circuit according to the module ID generated by the control module.

[0014] Embodiment 2 This embodiment provides a device for defending against power side channel attacks on mobile devices. The circuit block diagram is as follows: Figure 3 As shown, the device includes a microcontroller, a first variable resistance module 201 and a second variable resistance module 202 and a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor, a semiconductor device widely used in electronic circuits) 302 .

[0015] The microcontroller is implemented by MSP430 as a control module, including a central processing unit (CPU), flash memory, and a volatile random access memory (RAM), and the random algorithm is implemented by C language coding.

[0016] The first variable resistor module 201 consists of 8 load resistors and 8 MOSFETs, each load resistor is connected to the main circuit through a MOSFET, and these resistors are connected to the pins of the microcontroller. By controlling the gate voltage of the MOSFET, the microcontroller can switch the corresponding resistor in and out of the circuit. In this embodiment, the 8 different resistance values ​​are: 10Ω, 24Ω, 30Ω, 50Ω, 100Ω, 150Ω, 200Ω and 250Ω.

[0017] The second variable resistance module 202 is implemented by a digital resistor MCP41010, connected to the MSP430 via an SPI interface, and connected to the power supply circuit via a MOSFET 302.

[0018] The MOSFET 302 and the eight MOSFETs in the first variable resistance module 201 together form a switching module, and the switching operation of the MOSFET is controlled by a microcontroller, so that at a rate of 1 kHz, the current load value at each moment changes randomly, thereby generating continuous random current disturbances.

[0019] Embodiment 3 This embodiment provides a method for defending against power side channel attacks on mobile devices. The method comprises: Figure 3 The microcontroller MSP430 in the device shown executes, for example Figure 4 As shown, the method comprises the following steps: Step 1: Initialize the seed 1.1. After the MSP430 is powered on or reset, read the volatile RAM unit to obtain the 8-bit random seed; 1.2. Call the srand function to set the initial random seed.

[0020] Step 2: Generate module ID and control signal 2.1. Call the rand function to generate a 9-bit binary pseudo-random number sequence as the initial control command; 2.2. Divide the control command into two parts: take the highest bit as the module ID (to identify the variable resistor module currently in use); take the remaining 8 bits as the control signal to control the dynamic adjustment of the resistance value in the variable resistor module.

[0021] Step 3: Module selection and startup 3.1. If the module ID is 1, a switching signal "1" is generated, otherwise a switching signal "0" is generated; 3.2. Control the switching module operation according to the value of the switching signal: If the switching signal is "0", the MOSFET 302 is disconnected, the variable resistor module 202 is not connected to the circuit, and step 4.1 is continued; If the switching signal is "1", turn on MOSFET 302 and disconnect the remaining 8 MOSFETs, connect the variable resistor module 202 to the circuit, disconnect the variable resistor module 201, and continue to execute step 4.2.

[0022] Step 4: Switch the resistance value 4.1. If the module ID is 0, the 8 MOSFET switches are switched according to the state of each bit of the control signal. If the bit value is "1", the corresponding MOSFET is turned on and the corresponding resistor is connected to the circuit; if the bit value is "0", the corresponding MOSFET is disconnected so that the resistor does not participate in the current disturbance; 4.2. If the module ID is 1, the binary control signal is converted into a corresponding decimal value as the resistance value to be adjusted, and the MCP41010 is controlled by SPI to adjust the resistance.

[0023] Step 5: Execute step 2, step 3 and step 4 repeatedly at a rate of 1 kHz until the charger is unplugged.

Claims

1. A device for defending against power side channel attacks on mobile devices, characterized in that: The device includes: A control module, used to generate a random control signal to control the resistance value switched to the main circuit; N variable resistance modules, each of which can be connected to the main circuit and dynamically adjust its resistance value through control signals; The switching module is used to switch between multiple variable resistance modules. According to the module ID generated by the control module, the switching circuit determines which variable resistance module is connected to the main circuit.

2. The device for defending against power side channel attacks on mobile devices according to claim 1, characterized in that: The variable resistor module is composed of a plurality of load resistors with different resistance values, and each load resistor is connected to the main circuit through a switching module.

3. The device for defending against power side channel attacks on mobile devices according to claim 1 or 2, characterized in that: The switching module is composed of a plurality of MOSFETs.

4. A method for defending against power side channel attacks on mobile devices, using the device of claim 1, characterized in that: The following steps are involved: Step S1, initializing the seed, after the charger is plugged into a power source, obtaining an initial random seed; Step S2: Generate module ID and corresponding control signal based on random seed according to random algorithm, so as to identify different dynamic resistance modules and control them to be turned on or off; Step S3, determining the variable resistance module to be started according to the generated module ID; Step S4, the started variable resistance module dynamically adjusts the resistance value of the circuit connected thereto according to the control signal, thereby realizing intelligent adjustment of the charging parameters; Step S5, looping through steps S2, S3 and S4 at a set rate until the charger is unplugged.

5. The method for defending against power side channel attacks on mobile devices according to claim 4, characterized in that: Step S2 is specifically as follows: using a random algorithm to generate a 9-bit binary pseudo-random number sequence as an initial control command; dividing the control command into two parts: taking the highest bit as the module ID to identify the variable resistor module currently in use; taking the remaining 8 bits as the control signal to control the dynamic adjustment of the resistance value in the variable resistor module.

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