A resistive hardware encryption circuit

Abstract

The utility model provides a kind of resistance type hardware encryption circuit, including including control panel and decryption board connected by magnetic attraction, control panel includes first PCB substrate, and welding on the main control chip U1 of first PCB substrate, motor drive chip U2, three-terminal voltage stabilizing chip U3, preset resistance R3, preset resistance R4, preset resistance R5, preset resistance R6, filter capacitor C1, filter capacitor C2, filter capacitor C3, filter capacitor C4, filter capacitor C5, filter capacitor C6, filter capacitor C7, button K1, motor female connector J3, battery female connector J1 and magnetic male head J5, decryption board includes second PCB substrate, and welding on the encryption resistance R7 of second PCB substrate, encryption resistance R8, encryption resistance R9, encryption resistance R10 and magnetic female head J6.The utility model uses multiple resistance combinations as encryption key, combined with magnetic attraction convenient connection, with the advantages of low cost, high encryption strength, easy to operate, adapt to all kinds of low-cost equipment lock scene, strong practicality.

Description

Technical Field

[0001] This utility model relates to the field of hardware encryption technology, specifically to a resistive hardware encryption circuit, which is suitable for various device locks that require low-cost, high-reliability encryption. Background Technology

[0002] Existing device encryption solutions are mainly divided into two categories: software encryption and hardware encryption. Software encryption is low-cost but easily cracked and lacks sufficient security; hardware encryption, such as fingerprint modules and RFID cards, offers higher security but suffers from high cost and complex operation. For example, a single fingerprint encryption module typically costs over 30 yuan and requires fingerprint recording and database maintenance, making it unsuitable for low-cost scenarios; traditional resistor encryption often uses single resistor verification, resulting in limited encryption combinations and low cracking difficulty, failing to meet security requirements. Therefore, there is an urgent need for a hardware encryption solution that balances cost, security, and convenience. Summary of the Invention

[0003] This invention aims to solve the above-mentioned technical problems by providing a resistive hardware encryption circuit to address the issues of high cost, complex operation, or insufficient encryption reliability of existing encryption schemes.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a resistive hardware encryption circuit, including a control board and a decryption board connected by magnetic attraction.

[0005] The control board includes a first PCB substrate, and the following components soldered onto the first PCB substrate: a main control chip U1, a motor drive chip U2, a three-terminal voltage regulator chip U3, preset resistors R3, R4, R5, and R6, filter capacitors C1, C2, C3, C4, C5, C6, and C7, a button K1, a motor connector female J3, a battery connector female J1, and a magnetic male connector J5.

[0006] The decryption board includes a second PCB substrate, and encryption resistors R7, R8, R9, and R10, and a magnetic connector J6, which are soldered onto the second PCB substrate.

[0007] The magnetic male connector J5 and the magnetic female connector J6 are adapted to be connected, so that the decryption board and the control board are magnetically connected to form an electrical circuit. The three-terminal voltage regulator chip U3 supplies power to the control board, and the motor drive chip U2 receives the control signal from the main control chip U1 and drives the external motor to operate.

[0008] Pin 2 of the battery connector J1 is connected to pin Vin of the three-terminal voltage regulator chip U3, one end of filter capacitor C5, one end of filter capacitor C6, one end of filter capacitor C2, one end of filter capacitor C3, and pin VDD of the motor drive chip U2. Pin 1 of the battery connector J1 is connected to pin GND of the three-terminal voltage regulator chip U3, the other end of filter capacitor C5, the other end of filter capacitor C6, one end of filter capacitor C7, one end of button K1, and the main control chip U1. The pin VSS of the three-terminal voltage regulator chip U3 is connected to the other end of the filter capacitor C7, one end of the filter capacitor C1, and the pins VDD and 3.3V of the main control chip U1, respectively. The other end of one end of the button K1 is connected to the pin P71 of the main control chip U1. The pin P57 of the main control chip U1 is connected to one end of the preset resistor R3 and the pin 1 of the magnetic male connector J5, respectively. The pin P51 of the main control chip U1 is connected to the... One end of the preset resistor R4 is connected to pin 2 of the magnetic male connector J5. Pin P50 of the main control chip U1 is connected to one end of the preset resistor R5 and pin 3 of the magnetic male connector J5. Pin P55 of the main control chip U1 is connected to one end of the preset resistor R6 and pin 4 of the magnetic male connector J5. The other ends of the preset resistors R3, R4, R5, and R6 are all connected to 3.3V. The other end of the filter capacitor C1 is grounded. Pin P65 of the main control chip U1 is connected to pin INA of the motor drive chip U2. Pin P64 of the main control chip U1 is connected to pin INB of the motor drive chip U2. The other ends of the filter capacitors C2 and C3 are both grounded. Pin OUTA of the motor drive chip U2 is connected to one end of the filter capacitor C4 and pin 1 of the motor connector female connector J3. Pin OUTB of the motor drive chip U2 is connected to the other end of the filter capacitor C4 and pin 2 of the motor connector female connector J3.

[0009] Pins 1 to 4 of the magnetic female connector J6 are respectively connected to one end of the encryption resistors R7, R8, R9, and R10, and pin 5 of the magnetic female connector J6 is respectively connected to the other end of the encryption resistors R7, R8, R9, and R10.

[0010] When the magnetic male connector J5 and the magnetic female connector J6 are connected, four independent voltage divider circuits are formed to provide sampling signals for the main control chip U1.

[0011] The first PCB substrate has a size of 100mm*50mm, and the second PCB substrate has a size of 50mm*30mm. Both are made of FR-4 material and have a thickness of 1.6mm.

[0012] The main control chip U1 is model JZ8M2605_SOP20, the motor drive chip U2 is model TC118SS_SOP8, and the three-terminal voltage regulator chip U3 is model HT7533.

[0013] The filter capacitors C1, C3, C4, C6, and C7 are 100nF / 0805 surface mount capacitors; the filter capacitors C2 and C5 are 22uf / 0805 surface mount capacitors; the preset resistors R3, R4, R5, and R6 are 1KΩ / 0805 surface mount resistors; the encryption resistors R7, R8, R9, and R10 are 1KΩ, 10KΩ, 100KΩ, and 1MΩ 0805 packaged surface mount resistors, respectively; and the button K1 is a 6mm*6mm surface mount tactile switch.

[0014] The magnetic male connector J5 and the magnetic female connector J6 form a magnetic connection assembly, which is a 5PIN*2.54mm POGOPIN.

[0015] It also includes a power supply module, which consists of four AA dry batteries and is equipped with a plastic battery box with a reverse polarity protection structure. The power supply module is connected to the battery connector J1 via the male battery connector J2.

[0016] The advantages and positive effects of this utility model are: a resistor-type hardware encryption circuit that uses multiple sets of resistors as encryption keys, achieving up to 1024 encryption combinations. 4 This circuit design is far more difficult to crack than traditional single-resistor encryption schemes. Utilizing a POGOPIN magnetic connection, the operation requires only one step, significantly reducing steps and greatly improving convenience compared to digital password input or fingerprint enrollment. The total cost of all components is lower, far below that of fingerprint encryption modules, resulting in a 73% cost reduction. The circuit structure is simple to manufacture and assemble, making it widely applicable to various equipment and lock scenarios requiring low-cost, high-reliability encryption, such as smart locks, shared devices, and industrial control systems, demonstrating its high practicality. Attached Figure Description

[0017] Figure 1 This is a component layout diagram of a resistive hardware encryption circuit. Detailed Implementation

[0018] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0019] like Figure 1 As shown, a preferred embodiment of a resistive hardware encryption circuit includes a control board and a decryption board connected by magnetic attraction.

[0020] The control board includes a first PCB substrate, and the following components soldered onto the first PCB substrate: a main control chip U1, a motor drive chip U2, a three-terminal voltage regulator chip U3, preset resistors R3, R4, R5, and R6, filter capacitors C1, C2, C3, C4, C5, C6, and C7, a button K1, a motor connector female J3, a battery connector female J1, and a magnetic male connector J5.

[0021] The decryption board includes a second PCB substrate, and encryption resistors R7, R8, R9, and R10, and a magnetic connector J6, which are soldered onto the second PCB substrate.

[0022] The magnetic male connector J5 and the magnetic female connector J6 are adapted to be connected, so that the decryption board and the control board are magnetically connected to form an electrical circuit. The three-terminal voltage regulator chip U3 supplies power to the control board, and the motor drive chip U2 receives the control signal from the main control chip U1 and drives the external motor to operate.

[0023] Pin 2 of the battery connector J1 is connected to pin Vin of the three-terminal voltage regulator chip U3, one end of filter capacitor C5, one end of filter capacitor C6, one end of filter capacitor C2, one end of filter capacitor C3, and pin VDD of the motor drive chip U2. Pin 1 of the battery connector J1 is connected to pin GND of the three-terminal voltage regulator chip U3, the other end of filter capacitor C5, the other end of filter capacitor C6, one end of filter capacitor C7, one end of button K1, and the main control chip U1. The pin VSS of the three-terminal voltage regulator chip U3 is connected to the other end of the filter capacitor C7, one end of the filter capacitor C1, and the pins VDD and 3.3V of the main control chip U1, respectively. The other end of one end of the button K1 is connected to the pin P71 of the main control chip U1. The pin P57 of the main control chip U1 is connected to one end of the preset resistor R3 and the pin 1 of the magnetic male connector J5, respectively. The pin P51 of the main control chip U1 is connected to the... One end of the preset resistor R4 is connected to pin 2 of the magnetic male connector J5. Pin P50 of the main control chip U1 is connected to one end of the preset resistor R5 and pin 3 of the magnetic male connector J5. Pin P55 of the main control chip U1 is connected to one end of the preset resistor R6 and pin 4 of the magnetic male connector J5. The other ends of the preset resistors R3, R4, R5, and R6 are all connected to 3.3V. The other end of the filter capacitor C1 is grounded. Pin P65 of the main control chip U1 is connected to pin INA of the motor drive chip U2. Pin P64 of the main control chip U1 is connected to pin INB of the motor drive chip U2. The other ends of the filter capacitors C2 and C3 are both grounded. Pin OUTA of the motor drive chip U2 is connected to one end of the filter capacitor C4 and pin 1 of the motor connector female connector J3. Pin OUTB of the motor drive chip U2 is connected to the other end of the filter capacitor C4 and pin 2 of the motor connector female connector J3.

[0024] Pins 1 to 4 of the magnetic female connector J6 are respectively connected to one end of the encryption resistors R7, R8, R9, and R10, and pin 5 of the magnetic female connector J6 is respectively connected to the other end of the encryption resistors R7, R8, R9, and R10.

[0025] When the magnetic male connector J5 and the magnetic female connector J6 are connected, four independent voltage divider circuits are formed to provide sampling signals for the main control chip U1.

[0026] The first PCB substrate has a size of 100mm*50mm, and the second PCB substrate has a size of 50mm*30mm. Both are made of FR-4 material and have a thickness of 1.6mm.

[0027] The main control chip U1 is model JZ8M2605_SOP20, the motor drive chip U2 is model TC118SS_SOP8, and the three-terminal voltage regulator chip U3 is model HT7533.

[0028] The filter capacitors C1, C3, C4, C6, and C7 are 100nF / 0805 surface mount capacitors; the filter capacitors C2 and C5 are 22uf / 0805 surface mount capacitors; the preset resistors R3, R4, R5, and R6 are 1KΩ / 0805 surface mount resistors; the encryption resistors R7, R8, R9, and R10 are 1KΩ, 10KΩ, 100KΩ, and 1MΩ 0805 packaged surface mount resistors, respectively; and the button K1 is a 6mm*6mm surface mount tactile switch.

[0029] The magnetic male connector J5 and the magnetic female connector J6 form a magnetic connection assembly, which is a 5PIN*2.54mm POGOPIN.

[0030] It also includes a power supply module, which consists of four AA dry batteries and is equipped with a plastic battery box with a reverse polarity protection structure. The power supply module is connected to the battery connector J1 via the male battery connector J2.

[0031] Selection of the best implementation method:

[0032] Control Board: The first PCB substrate is made of FR-4 material, measuring 100mm*50mm and 1.6mm thick, ensuring structural stability and electrical performance. The main control chip U1 (model JZ8M2605_SOP20) is soldered onto the substrate to read voltage sampling values ​​and output control signals; the motor drive chip U2 (model TC118SS_SOP8) receives signals from the main control chip U1 to drive the motor; and the three-terminal voltage regulator chip U3 (model HT7533) converts the input voltage into a stable voltage to power the control board. In addition, the control board also solders preset resistors R3-R6 (1KΩ / 0805, accuracy ±1%), filter capacitors C1-C7 (surface mount type, filtering circuit noise), button K1 (6mm*6mm surface mount tactile switch, used for triggering pairing), motor connector (2PIN*2.54mm), battery connector (2.54mm), and magnetic female connector (POGOPIN type).

[0033] Decryption board: A second PCB substrate made of FR-4 material, measuring 50mm*30mm and 1.6mm thick, is compact and portable. Encryption resistors R7-R10 (1KΩ, 10KΩ, 100KΩ, and 1MΩ respectively, 0805 package, ±1% accuracy) are soldered onto the substrate to form multiple encryption combinations; at the same time, magnetic male connectors (POGOPIN type) that are compatible with the magnetic female connector of the control board are soldered on to achieve quick docking with the control board.

[0034] Magnetic connection assembly and power supply module: The magnetic connection assembly uses 5PIN*2.54mm POGOPIN male and female connectors. The male connector is soldered to the decryption board, and the female connector is soldered to the control board. Precise contact is achieved through magnetic force, ensuring a stable connection and convenient operation. The power supply module uses four AA dry batteries (total voltage 6V). The battery box has a plastic shell with reverse polarity protection to prevent damage to the circuitry.

[0035] Assembly steps of the best implementation method:

[0036] 1. Control Board Soldering: A step-by-step soldering process is adopted. First, the main control chip U1, motor drive chip U2, and three-terminal voltage regulator chip U3 are soldered using a hot air gun. The hot air gun temperature is set to 320-350℃ and the air speed is level 2 to avoid damaging the chips with high temperature. Then, the preset resistors R3-R6 and filter capacitors C1-C7 are soldered using a soldering iron. The soldering iron temperature is 300-320℃ to ensure that the polarity of the components is correct (the long lead of the capacitor is the positive terminal). Finally, the POGOPIN magnetic female connector, motor connector, battery connector, and button K1 are soldered. After soldering, all solder joints are checked to ensure that there are no cold solder joints, bridging, or false solder joints, and that the pins are not oxidized and detached.

[0037] 2. Decryption board soldering: First, solder the encryption resistors R7-R10 to the second PCB substrate according to the design position. The soldering requirements are the same as those for the control board. Then, solder the POGOPIN magnetic male connector, ensuring that the male connector pins are fully attached to the substrate pads. After soldering, clean the solder slag to ensure that the magnetic surface is flat and without protrusions.

[0038] 3. Overall Assembly: Correctly insert 4 AA dry batteries into the battery box (corresponding to the positive and negative markings to avoid reverse connection), and connect them to the control board through the battery connector; connect the external motor to the motor drive terminal of the control board through the 2-pin connector; hold the decryption board and align the POGOPIN magnetic male connector with the magnetic female connector of the control board, using the magnetic force to achieve a tight fit, ensuring that there is no looseness or poor contact after docking.

[0039] Functional testing and verification of the best implementation method:

[0040] 1. Pairing Operation: Press button K1 on the control board. At this time, pin 11 of the main control chip U1 outputs a high level (measured with a multimeter, the voltage is 3.3V±0.1V). Keep the button pressed and magnetically connect the decryption board to the control board. U1 begins to read the voltages V1-V4 of the circuit formed by the encryption resistors R7-R10 and the preset resistors R3-R6, and converts them into AD sampling values. Record the AD values ​​corresponding to V1-V4 at this time as follows: V1 (R7=1KΩ) AD value 102, V2 (R8=10KΩ) AD value 512, V3 (R9=100KΩ) AD value 922, V4 (R10=1MΩ) AD value 1023. U1 stores this set of AD values ​​in its internal storage module. After successful pairing, release button K1. The button will spring back, and pin 11 of U1 will return to a low level, completing the pairing.

[0041] 2. Unlock Test: Disconnect the magnetic connection between the decryption board and the control board, then realign the magnetic connection. U1 reads the current AD values ​​of V1-V4 in real time and compares them with the stored AD values ​​(allowing an error range of ±2, considering the accuracy of the adapter resistor and circuit noise). When the AD value deviation is within the allowable range, pin 12 of U1 outputs a high level (3.3V±0.1V). After receiving the signal, the motor driver chip U2 drives the motor to reverse, with a speed of approximately 500rpm. After 2 seconds, the motor stops, the device lock is successfully opened, and the unlock function is verified.

[0042] 3. Locking Test: With the decryption board disconnected in the unlocked state, U1 detects the POGOPIN magnetic disconnect signal. After a 3-second delay, pin 11 of U1 outputs a high level, and the motor driver chip U2 drives the motor to rotate forward at a speed of approximately 500 rpm. After 2 seconds, the motor stops, the device lock is closed, and the locking function is verified.

[0043] 4. Error verification: Replace the encryption resistor R7 on the decryption board with 2KΩ (keeping the other resistors unchanged), and reconnect it magnetically to the control board; U1 reads the AD value of V1 as 204, which deviates from the stored 102 by more than ±2. At this time, U1 does not output a high-level signal, the motor does not move, the device remains locked, and the encryption validity verification is passed.

[0044] A resistive hardware encryption circuit uses multiple resistor combinations as encryption keys, achieving up to 1024 encryption combinations. 4 This circuit design is far more difficult to crack than traditional single-resistor encryption schemes. Utilizing a POGOPIN magnetic connection, the operation requires only one step, significantly reducing steps and greatly improving convenience compared to digital password input or fingerprint enrollment. The total cost of all components is lower, far below that of fingerprint encryption modules, resulting in a 73% cost reduction. The circuit structure is simple to manufacture and assemble, making it widely applicable to various equipment and lock scenarios requiring low-cost, high-reliability encryption, such as smart locks, shared devices, and industrial control systems, demonstrating its high practicality.

[0045] The embodiments of this utility model have been described in detail above, but the content described is only a preferred embodiment of this utility model and should not be considered as limiting the scope of implementation of this utility model. All equivalent changes and improvements made within the scope of this utility model should still fall within the scope of this patent.

Claims

1. A resistive hardware encryption circuit, characterized in that: Including a control board and a decryption board connected by magnetic attraction, The control board includes a first PCB substrate, and the following components soldered onto the first PCB substrate: a main control chip U1, a motor drive chip U2, a three-terminal voltage regulator chip U3, preset resistors R3, R4, R5, and R6, filter capacitors C1, C2, C3, C4, C5, C6, and C7, a button K1, a motor connector female J3, a battery connector female J1, and a magnetic male connector J5. The decryption board includes a second PCB substrate, and encryption resistors R7, R8, R9, and R10, and a magnetic connector J6, which are soldered onto the second PCB substrate. The magnetic male connector J5 and the magnetic female connector J6 are adapted to be connected, so that the decryption board and the control board are magnetically connected to form an electrical circuit. The three-terminal voltage regulator chip U3 supplies power to the control board, and the motor drive chip U2 receives the control signal from the main control chip U1 and drives the external motor to operate. Pin 2 of the battery connector J1 is connected to pin Vin of the three-terminal voltage regulator chip U3, one end of filter capacitor C5, one end of filter capacitor C6, one end of filter capacitor C2, one end of filter capacitor C3, and pin VDD of the motor drive chip U2. Pin 1 of the battery connector J1 is connected to pin GND of the three-terminal voltage regulator chip U3, the other end of filter capacitor C5, the other end of filter capacitor C6, one end of filter capacitor C7, one end of button K1, and the main control chip U1. The pin VSS of the three-terminal voltage regulator chip U3 is connected to the other end of the filter capacitor C7, one end of the filter capacitor C1, and the pins VDD and 3.3V of the main control chip U1, respectively. The other end of one end of the button K1 is connected to the pin P71 of the main control chip U1. The pin P57 of the main control chip U1 is connected to one end of the preset resistor R3 and the pin 1 of the magnetic male connector J5, respectively. The pin P51 of the main control chip U1 is connected to the... One end of the preset resistor R4 is connected to pin 2 of the magnetic male connector J5. Pin P50 of the main control chip U1 is connected to one end of the preset resistor R5 and pin 3 of the magnetic male connector J5. Pin P55 of the main control chip U1 is connected to one end of the preset resistor R6 and pin 4 of the magnetic male connector J5. The other ends of the preset resistors R3, R4, R5, and R6 are all connected to 3.3V. The other end of the filter capacitor C1 is grounded. Pin P65 of the main control chip U1 is connected to pin INA of the motor drive chip U2. Pin P64 of the main control chip U1 is connected to pin INB of the motor drive chip U2. The other ends of the filter capacitors C2 and C3 are both grounded. Pin OUTA of the motor drive chip U2 is connected to one end of the filter capacitor C4 and pin 1 of the motor connector female connector J3. Pin OUTB of the motor drive chip U2 is connected to the other end of the filter capacitor C4 and pin 2 of the motor connector female connector J3. Pins 1 to 4 of the magnetic female connector J6 are respectively connected to one end of the encryption resistors R7, R8, R9, and R10, and pin 5 of the magnetic female connector J6 is respectively connected to the other end of the encryption resistors R7, R8, R9, and R10. When the magnetic male connector J5 and the magnetic female connector J6 are connected, four independent voltage divider circuits are formed to provide sampling signals for the main control chip U1.

2. The resistive hardware encryption circuit according to claim 1, characterized in that: The first PCB substrate has a size of 100mm*50mm, and the second PCB substrate has a size of 50mm*30mm. Both are made of FR-4 material and have a thickness of 1.6mm.

3. The resistive hardware encryption circuit according to claim 2, characterized in that: The main control chip U1 is model JZ8M2605_SOP20, the motor drive chip U2 is model TC118SS_SOP8, and the three-terminal voltage regulator chip U3 is model HT7533.

4. The resistive hardware encryption circuit according to claim 3, characterized in that: The filter capacitors C1, C3, C4, C6, and C7 are 100nF / 0805 surface mount capacitors; the filter capacitors C2 and C5 are 22uf / 0805 surface mount capacitors; the preset resistors R3, R4, R5, and R6 are 1KΩ / 0805 surface mount resistors; the encryption resistors R7, R8, R9, and R10 are 1KΩ, 10KΩ, 100KΩ, and 1MΩ 0805 packaged surface mount resistors, respectively; and the button K1 is a 6mm*6mm surface mount tactile switch.

5. The resistive hardware encryption circuit according to claim 4, characterized in that: The magnetic male connector J5 and the magnetic female connector J6 form a magnetic connection assembly, which is a 5PIN*2.54mm POGOPIN.

6. The resistive hardware encryption circuit according to claim 5, characterized in that: It also includes a power supply module, which consists of four AA dry batteries and is equipped with a plastic battery box with a reverse polarity protection structure. The power supply module is connected to the battery connector J1 via the male battery connector J2.

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