Card insertion type U disk with multi-interface fingerprint identification function

Abstract

The invention discloses a multi-interface fingerprint identification card type USB flash disk, which belongs to the technical field of USB flash disks, and comprises a hardware core module, a software interaction module and a software-hardware combination module, the hardware core module is a physical basis of the USB flash disk, and is responsible for interface adaptation, fingerprint acquisition, data storage and state indication; the hardware core module comprises a multi-interface protocol module, a dual-master control cooperation module, a multi-specification plug-in card adaptation module and a fingerprint identification module; and the software interaction module is used for realizing fingerprint management, authority configuration and log recording functions through a four-layer architecture. In the use process, the plug-in type USB flash disk with the multi-interface fingerprint identification function is compatible with Lightning, TYPE-C and USB-A interfaces, adapts to multiple devices such as a computer, a mobile phone, a tablet computer and an industrial controller, does not need an additional adapter, is plug-and-play, improves the convenience of a use scene, is matched with a high-speed protocol of USB3.2 and above, gives consideration to the transmission efficiency and the device compatibility, has multiple permissions, and is convenient to use. And efficient protection of the information is realized through three-level permission classification.

Description

Technical Field

[0001] This invention relates to the field of USB flash drive technology, specifically to a multi-interface fingerprint-recognition plug-in USB flash drive. Background Technology

[0002] USB flash drives can meet daily data storage and file transfer needs, support mobile office modes, and have the advantages of stable storage performance and high read / write speed. They are also highly portable, weighing only a few grams, and can be embedded in keychains or placed in pockets. However, precisely because of their extremely small size, USB flash drives are easily lost. If the USB flash drive is not password-locked, data loss can occur. To overcome this drawback, existing technology 1 (Chinese patent application No. 201510182462.4, application date 2015-04-17) discloses a fingerprint lock USB flash drive, which includes a storage disk; a fingerprint reader is provided on the outer surface of the storage disk, and a USB plug is provided at one end; the storage disk contains a fingerprint recognition circuit, a storage circuit, and an alarm circuit; the fingerprint recognition circuit is connected to the fingerprint reader, the storage circuit, and the alarm circuit respectively; the storage circuit stores authorized information and sends the information to the fingerprint recognition circuit and the alarm circuit; the fingerprint recognition circuit compares the user's fingerprint with the authorized information; the alarm circuit can send the location of the USB flash drive to the authorized person. During use, it not only prevents others from reading the contents of the USB drive, but also helps the user retrieve the USB drive. It has a simple structure and is easy to use. Prior art 2 (Chinese patent application No. 201821167661.3, application date 2018-07-23) describes a fingerprint lock USB drive, which includes a shell and a slot. A first slot is formed on one side of the shell, and a USB plug is inserted into the first slot. One end of the USB plug is connected to a circuit board. A flash memory chip is embedded on the surface of the circuit board. A connecting block is connected to one side of the circuit board, and both ends of the connecting block... Both are fixedly installed with hollow cup motors. The output ends of the two hollow cup motors are connected to the transmission with bolts. One end of each bolt is threaded with a screw tube. One end of each screw tube is fixed with a fixing block. One end of the fixing block is glued to the inner wall of the housing. A fourth slot is opened on the front side of the housing. When in operation, it increases the security of information stored by users by using a fingerprint password lock encryption method, increases the difficulty for spies to crack corporate information, and facilitates users to store trade secrets. The hollow cup motors also allow operators to hide the USB plug.

[0003] In practical use, USB flash drives not only need to be connected to a USB interface, but also need to be used in other scenarios. However, the USB flash drives mentioned in the above application lack multi-specification card compatibility and only support a single chip, making them unusable in professional scenarios. Consequently, their application scope is limited and their use is restricted. Therefore, we propose a multi-interface fingerprint recognition card-type USB flash drive to solve the aforementioned problems. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-interface fingerprint recognition card-type USB flash drive to solve the problems mentioned in the background art, such as the lack of multi-specification card compatibility, support for only a single chip, inability to be used in professional scenarios, and thus limited application scope and significant limitations in actual use.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a multi-interface fingerprint recognition card-type USB flash drive, comprising a hardware core module, a software interaction module, and a hardware-software integrated module. The hardware core module is the physical foundation of the USB flash drive, responsible for interface adaptation, fingerprint acquisition, data storage, and status indication. It includes a multi-interface protocol module, a dual-controller collaborative module, a multi-specification card adaptation module, a fingerprint recognition module, and a lighting control module. The software interaction module implements fingerprint management, permission configuration, and log recording functions through a four-layer architecture, including an APP interaction software module. It also implements fingerprint hierarchy, divided into administrator, ordinary user, and visitor levels. The hardware-software integrated module is the hub connecting hardware actions and software logic, ensuring seamless functional operation. It includes a multi-interface-fingerprint-permission-storage linkage interaction module and an exception handling control module.

[0006] Preferably, the multi-interface protocol module covers three interfaces: Lightning interface, TYPE-C interface, and USB-A interface, adapting to different terminal devices. The Lightning interface integrates a C94MFi chip and a CH224K chip. The C94MFi chip completes iOS device certification, and the CH224K chip converts the protocol to USB 2.0, supporting Apple mobile phones and tablets for connection. The TYPE-C interface is equipped with an IP2721PD chip, which can detect the protocol type and adjust the transmission rate according to permissions, making it compatible with Android phones and laptops; The USB-A interface integrates a W25Q16JV chip, which automatically loads the driver and has the function of prompting the user's permission scope through a system pop-up window when connected to a computer. The dual-master control collaborative module adopts a flash memory controller chip + microcontroller chip architecture. The flash memory controller chip is model WA8372, and the microcontroller chip is model STC89C52. The STC89C52 serves as the fingerprint control core and connects to an external EEPROM chip via an I2C interface. The external EEPROM chip is model AT24C512 with a capacity of 512KB. At the same time, the STC89C52 drives the AS608 through a circuit connection. The AS608 is a fingerprint recognition module and is a fingerprint recognition chip. The WA8372 serves as the core of flash memory control, communicating with the STC89C52 via GPIO command lines, UART data lines, and permission data transmission lines. It also coordinates storage partition control and lighting adjustment. It has a built-in 1ms timer; if no STC89C52 instruction reception confirmation signal is received within 100ms after the instruction is sent, it will retransmit, up to three times. Permission transmission uses CRC8 checksum to prevent errors. The GPIO instruction line is used to trigger the fingerprint control mode, the UART data line is used to transmit operation instructions and results, and the permission data transmission line is used to transmit permission level codes 0x01, 0x02, and 0x03. Meanwhile, the Lightning, Type-C, and USB-A interfaces are all electrically connected to the WA8372 flash memory controller chip, which coordinates data transmission and access control.

[0007] Preferably, the AT24C512 is divided into a fingerprint template area and an access control area. The fingerprint template area is 480KB. Each fingerprint template contains feature points and a verification code, occupying 6KB. It stores 50 to 80 encrypted feature points. Each encrypted feature point stores 128 bytes. The 480KB area stores 80 sets. The permission configuration area is 32KB, which stores the permission level and access permissions for each fingerprint group. Each group of permission data occupies 400 bytes, and 32KB stores 80 groups.

[0008] Preferably, the multi-specification card adapter module uses a 20-pin compatible slot + multi-channel analog switch, supporting TF, SD, and CF memory card access. The multi-channel analog switch uses a CD4051 chip. The partitioning logic of the multi-specification card adapter module is as follows: it connects to the peripheral interface of the WA8372. After the WA8372 reads the card capacity, it automatically assigns permissions to associated partitions. The administrator partition has 20% capacity with read and write permissions, the ordinary user partition has 60% capacity, the ordinary user partition is read-only, the administrator partition is read-write, the visitor partition has 20% capacity, and all users are read-only. Cross-partition access is prohibited through the "partition selection command".

[0009] Preferably, the core of the fingerprint recognition module is a fingerprint recognition chip, model AS608, driven by STC89C52. The fingerprint enrollment process is as follows: during enrollment, fingerprints are collected 3 times, 50-80 feature points are extracted and encrypted and written to AT24C512; during verification, the current fingerprint features are collected and compared with 80 sets of templates in AT24C512 one by one. If the matching degree is ≥90%, it is considered successful, and the result and the permission level code are fed back to WA8372.

[0010] Preferably, the lighting control module, in addition to the original red and blue LEDs, also has a green LED dedicated to the administrator, which is connected to the GPIO pin of WA8372 through a transistor driving circuit, where GPIO2 = red light, GPIO3 = blue light, GPIO4 = green light, and the transistor model is S8050. The status indicators are as follows: initially, the red light is on; when the administrator successfully verifies, the green light is on; when the regular user successfully verifies, the blue light is on; when the visitor successfully verifies, the blue light flashes once per second; and when verification fails, the red light flashes once per second. The different lights visually distinguish permissions and device status.

[0011] Preferably, the APP interactive software module is divided into a UI layer, a permission management layer, a business layer, and a communication layer. The UI layer provides a visual operation interface, including a fingerprint management interface to display the number of fingerprints and permission levels, a permission configuration interface to select permission types and check accessible folders, and an access log interface to view access time and operation type. The UI layer displays different levels of permission codes transmitted by WA8372. The permission management layer is the core of the APP's interactive software module, featuring three major algorithms: Fingerprint capacity management algorithm: displays the number of used and available fingerprints in real time, and displays a pop-up warning "Capacity is about to be full, please delete unused fingerprints" when approaching the 80-group limit; Permission hierarchy algorithm: divides permissions into three levels: Administrator: full permissions, can add and delete fingerprints, modify partition permissions, and view logs; Regular user: only accesses specified partitions, read and write configurable; Visitor: only reads the visitor partition, write and delete are prohibited, bound by permission level code + partition ID; Access log recording algorithm: records the timestamp + permission level + interface type + operation type for each operation, logs are stored locally and can be exported to Excel, and can only be viewed by the administrator. The business layer optimizes the fingerprint processing flow, while the communication layer has the function of preventing permission data from being tampered with.

[0012] In the above-mentioned APP interactive software module, the specific workflow of the business layer is as follows: S1. Entry process: APP initiates "entry request" → WA8372 forwards to STC89C52 → STC89C52 drives AS608 to collect fingerprints 3 times (the clearest image is selected by deduplication algorithm) → extract 50~80 feature points → encrypt (AES-128) and write to AT24C512 → APP synchronously stores template backup (to avoid template loss due to hardware failure); S2. Verification process: APP initiates "verification request" → AS608 collects the current fingerprint → STC89C52 reads 80 sets of templates in AT24C512 and compares them one by one (matching degree ≥90% is considered successful) → returns "success + permission level code" to WA8372 → WA8372 controls the lights and unlocks the partition; S3: Deletion process (administrator only): APP selects the fingerprint ID to be deleted → sends "delete command" to WA8372 → STC89C52 erases the corresponding template and permission data in AT24C512 → APP updates the number of used fingerprints; The communication layer's workflow is as follows: The communication layer monitors the current device's connected interface type (Lightning, Type-C, USB-A) in real time, and calls the corresponding driver for each interface—the Lightning interface calls the C94MFi certified driver to ensure iOS device compatibility, the Type-C interface calls the IP2721PD protocol driver to match the transmission rate, and the USB-A interface calls the W25Q16JV driver for automatic loading, establishing a stable hardware communication link. Simultaneously, the communication layer implements data encapsulation and format conversion: after receiving instructions from the service layer (such as fingerprint enrollment instruction 0x01), the communication layer processes the data according to hardware conventions. The data is encapsulated in a "frame format" (instruction header 0xAA + instruction content + CRC8 checksum). At the same time, the digital signal from the APP is converted into an electrical signal that the hardware can recognize, avoiding transmission failure due to data format incompatibility. Moreover, the communication layer implements transmission monitoring and feedback forwarding: during data transmission, the communication layer monitors the transmission status in real time. If a signal interruption or checksum failure occurs, a retransmission mechanism is immediately triggered (up to 3 times). After receiving the hardware feedback result (such as operation success 0x00), the frame header and checksum are removed, the core result is converted into a signal that the APP can parse, and forwarded to the business layer for processing, ensuring the accuracy and timeliness of bidirectional data transmission.

[0013] Preferably, the multi-interface-fingerprint-permission-storage linkage interaction module includes administrator permission interaction and multi-interface switching interaction. The workflow of administrator permission interaction is as follows: interface access and initialization, APP wake-up and permission detection, fingerprint verification and permission activation, and permission operation and synchronization.

[0014] Preferably, the workflow of the multi-interface switching interaction is as follows: initial connection, new interface access detection and secondary verification and protocol switching, as well as permission maintenance and data access.

[0015] Preferably, the anomaly handling control module provides solutions for fingerprint template corruption, permission conflicts, and fingerprint capacity issues. When a fingerprint template is corrupted, the STC89C52 checks the CRC code when reading the fingerprint template. If this fails, an APP pop-up window is triggered, supporting restoration from APP backup or re-entry, but only administrators can operate on this. The CRC code is an error detection technology used to verify data integrity. It calculates a fixed-length checksum using a specific algorithm, and then compares the checksum to determine if the data was corrupted during transmission or storage due to interference or errors. In case of permission conflicts, requests are sorted by permission priority and access time, prioritizing higher-priority requests and sending a "partition occupied" warning with a flashing red light to lower-priority devices. When fingerprint capacity is full, a pop-up warning is displayed when ≥75 used fingerprints are available, and a list of fingerprints to be deleted is displayed sorted by "last used time." Operations are prohibited when only one administrator fingerprint remains to prevent permission control issues.

[0016] Compared with the prior art, the beneficial effects of this invention are: It adopts a novel structural design and, through the inclusion of a multi-interface protocol module, enables the USB flash drive to be compatible with Lightning, Type-C, and USB-A interfaces, thereby expanding the scope of use of the USB flash drive and improving its convenience. The specific details are as follows: This multi-interface fingerprint-recognition card-type USB flash drive is compatible with Lightning, Type-C, and USB-A interfaces, and can be used with various devices such as computers, mobile phones, tablets, and industrial controllers. No additional adapters are required; it is plug-and-play, improving the convenience of use. With the USB 3.2 and higher high-speed protocol, it balances transmission efficiency and device compatibility. Moreover, it has multiple permissions, and the three-level hierarchical permission system enables efficient information protection.

[0017] This multi-interface fingerprint recognition card-type USB flash drive, through the STC89C52 expanded EEPROM, increases the fingerprint storage capacity to 80 groups. The 480KB fingerprint template area stores 6KB templates per group, and the 32KB permission configuration area stores permission data in 400-byte groups. Simultaneously, the app displays the used and available fingerprints in real time, and a pop-up warning appears when the limit is approaching. This meets the fingerprint enrollment needs of families with multiple members and businesses with multiple employees while avoiding chaotic capacity management.

[0018] Furthermore, through the permission hierarchy algorithm of the software interaction module, permissions are divided into three levels: administrator (0x01, full permissions), ordinary user (0x02, limited access), and visitor (0x03, read-only visitor partition), and are bound to storage partitions (administrator partition 20% capacity, ordinary user 60%, visitor 20%). Users with different permissions can only access their corresponding partitions. For example, ordinary users cannot view administrator's private data, and in enterprise scenarios, visitors cannot modify core files, significantly improving data security.

[0019] This multi-interface fingerprint recognition card-type USB flash drive features multiple layers of security protection from data acquisition and transmission to storage. After fingerprint template acquisition, it is encrypted and written to the AT24C512. During authorized data transmission, in addition to CRC8 checksum error prevention (such as avoiding mistransmission of administrator privileges), a dynamic key is generated using the Diffie-Hellman algorithm for encryption. Switching between interfaces requires secondary fingerprint verification to prevent unauthorized access by low-privilege users using new interfaces. The CRC code is verified when reading the fingerprint template, and damaged templates can be restored from app backups. These multiple layers of protection prevent data tampering, leakage, and loss, safeguarding family privacy and enterprise core data security.

[0020] This multi-interface fingerprint recognition card-type USB flash drive is equipped with various indicator lights: an initial red light, a green light when the administrator successfully verifies the device, a blue light when a regular user successfully verifies the device, a blue light that flashes once per second when a visitor successfully verifies the device, and a red light that flashes once per second when the verification fails. These light differences allow for a clear and intuitive distinction between permissions and device status. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall workflow structure of the present invention; Figure 2 This is a schematic diagram of the workflow structure of the multi-interface protocol module of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figures 1-2 The present invention provides the following technical solution: a multi-interface fingerprint recognition card-type USB flash drive.

[0024] Example 1: Includes a hardware core module, a software interaction module, and a hardware-software integrated module. The hardware core module is the physical foundation of the USB flash drive and is responsible for interface adaptation, fingerprint acquisition, data storage, and status indication. The hardware core module includes a multi-interface protocol module, a dual-master control collaboration module, a multi-specification card adapter module, a fingerprint recognition module, and a lighting control module. The multi-interface protocol module covers three interfaces: Lightning, Type-C, and USB-A, adapting to different terminal devices. The Lightning interface integrates the C94MFi chip and the CH224K chip. The C94MFi chip completes iOS device certification, and the CH224K chip converts the protocol to USB 2.0, supporting Apple mobile phones and tablets. The TYPE-C interface is equipped with an IP2721PD chip, which can detect the protocol type and adjust the transmission rate according to permissions, making it compatible with Android phones and laptops; The USB-A interface integrates a W25Q16JV chip, which automatically loads the driver and has the function of prompting the user's permission scope through a system pop-up window when connected to a computer. In the aforementioned multi-interface protocol modules, the Lightning interface integrates the C94MFi and CH224K chips. The C94MFi chip completes iOS device authentication, enabling the device to connect and communicate normally with Apple iPhones, iPads, and other iOS devices. The CH224K chip converts the Lightning interface protocol to USB 2.0, facilitating subsequent data transfer and processing, and ensuring stable data transmission to the WA8372 flash memory controller chip for further operations. The Type-C interface, equipped with the IP2721PD chip, can adjust the transmission rate according to different user permissions. When an administrator connects, the transmission rate can reach 5Gbps; when a regular user connects, the rate is 2Gbps. This ensures the needs of users with different permissions while effectively managing data transmission, and simultaneously transmitting data to the WA8372 chip for processing. Furthermore, the USB-A interface integrates the W25Q16JV chip, which automatically loads the driver, enabling the computer to recognize the USB flash drive and communicate normally when the device is connected. The W25Q16JV chip can also send permission level prompts to the computer, informing the user of the current permission scope through a system pop-up window, such as "Currently a regular user, only able to access D:\Regular User Folder", making it easy for the user to know the operation permissions, and the data can be transmitted to the WA8372 chip for processing.

[0025] The dual-master control collaborative module adopts a flash memory controller chip + microcontroller chip architecture. The flash memory controller chip is model WA8372, and the microcontroller chip is model STC89C52. The STC89C52 serves as the fingerprint control core and connects to an external EEPROM chip via an I2C interface. The external EEPROM chip is model AT24C512 with a capacity of 512KB. At the same time, the STC89C52 drives the AS608 through a circuit connection. The AS608 is a fingerprint recognition module and is a fingerprint recognition chip. The WA8372 serves as the core of flash memory control, communicating with the STC89C52 via GPIO command lines, UART data lines, and permission data transmission lines. It also coordinates storage partition control and lighting adjustment. It has a built-in 1ms timer; if no STC89C52 instruction reception confirmation signal is received within 100ms after the instruction is sent, it will retransmit, up to three times. Permission transmission uses CRC8 checksum to prevent errors. The GPIO instruction line is used to trigger the fingerprint control mode, the UART data line is used to transmit operation instructions and results, and the permission data transmission line is used to transmit permission level codes 0x01, 0x02, and 0x03. Meanwhile, the Lightning, Type-C, and USB-A interfaces are all electrically connected to the WA8372 flash memory controller chip, which coordinates data transmission and access control.

[0026] In the aforementioned dual-master collaborative module, the corresponding connection between the I2C interface pins of the STC89C52 and the AT24C512 is fixed. Simultaneously, the power supply circuit ensures stable communication. The I2C interface of the STC89C52 is explicitly assigned as "SDA=P2.0" (serial data line, responsible for data transmission) and "SCL=P2.1" (serial clock line, responsible for synchronizing data transmission timing). These two pins are directly connected to the corresponding SDA and SCL pins of the external EEPROM chip AT24C512, forming the core link of I2C communication. Meanwhile, the VCC pin of the AT24C512 is connected to a 3.3V voltage (output by the LM1117 voltage regulator chip to ensure voltage stability). The GND pin shares a common ground with the GND pins of the STC89C52 and the entire system, providing a stable power supply for the EEPROM chip and preventing voltage fluctuations from affecting the stability of I2C communication. The GPIO instruction line is used to trigger the fingerprint control mode. The specific workflow is as follows: A high level is preset as the trigger signal. When the WA8372 needs to initiate fingerprint-related operations (such as fingerprint enrollment, verification, or deletion), it controls its GPIO instruction line pin to output a high level. This high-level signal is transmitted to the corresponding GPIO pin of the STC89C52 as a hardware trigger signal to "enter fingerprint control mode." When the WA8372 receives an external command (such as a "fingerprint verification request" sent by the APP), it first determines the current system status (such as whether it is idle). If the conditions are met, it immediately switches the GPIO instruction line to a high level and simultaneously sends a specific fingerprint operation command (such as "0x02" representing a verification command) to the STC89C52 via the UART data line. The STC89C52 will monitor its GPIO instruction line in real time. The STC89C52 controls the GPIO command line. When a high level is detected, it immediately stops the current non-core task (such as the low-power mode in idle state) and switches to "fingerprint control mode". In this mode, the STC89C52 will prioritize receiving specific operation instructions on the UART data line and start the corresponding hardware driver (such as driving the AS608 fingerprint sensor to collect fingerprints or reading the fingerprint template in the AT24C512 via I2C). After the fingerprint operation is completed (such as successful / failed verification or enrollment completed), the STC89C52 will send the result back to the WA8372 via the UART data line (such as "0x00" representing success). After receiving the result, the WA8372 controls the GPIO command line to switch to a low level. When the STC89C52 detects the low level, it exits "fingerprint control mode" and returns to the normal standby state. The UART data line is used to transmit operation commands and results. The specific workflow is as follows: the UARTTx / Rx pins of WA8372 and STC89C52 are cross-connected (WA8372Tx connects to STC89C52Rx, and WA8372Rx connects to STC89C52Tx) and grounded together to build a bidirectional transmission link. Parameters such as a preset baud rate of 9600bps and 8 data bits are used. Commands (e.g., 0x02 for fingerprint verification) and results (e.g., 0x00 for successful operation) are defined using 1-byte hexadecimal encoding. After WA8372 triggers the fingerprint control mode, it sends commands through the UART; STC89C52 receives, parses, and executes the operation, and then feeds back the results through the UART, realizing bidirectional transmission of commands and results.

[0027] The AT24C512 is divided into a fingerprint template area and an access configuration area. The fingerprint template area is 480KB. Each fingerprint template contains feature points and a verification code, occupying 6KB. It stores 50 to 80 encrypted feature points. Each encrypted feature point stores 128 bytes. The 480KB area stores 80 sets. The permission configuration area is 32KB, which stores the permission level and access permissions for each fingerprint group. Each group of permission data occupies 400 bytes, and 32KB stores 80 groups.

[0028] The multi-specification card adapter module uses a 20-pin compatible slot and a multi-channel analog switch, supporting TF, SD, and CF memory cards. The multi-channel analog switch uses a CD4051 chip. The partitioning logic of the multi-specification card adapter module is as follows: it connects to the peripheral interface of the WA8372. After the WA8372 reads the card capacity, it automatically assigns permissions and associated partitions. The administrator partition has 20% capacity, read and write permissions; the ordinary user partition has 60% capacity, ordinary users are read-only, administrators are read and write, the guest partition has 20% capacity, and all users are read-only. Cross-partition access is prohibited through the "partition selection command".

[0029] The core of the fingerprint recognition module is the fingerprint recognition chip, model AS608, driven by STC89C52. The fingerprint enrollment process is as follows: during enrollment, fingerprints are collected 3 times, 50-80 feature points are extracted and encrypted and written to AT24C512; during verification, the current fingerprint features are collected and compared with 80 sets of templates in AT24C512 one by one. If the matching degree is ≥90%, it is considered successful, and the result and the permission level code are fed back to WA8372.

[0030] The specific workflow of the fingerprint recognition module described above is as follows: The user clicks "Add Fingerprint" on the fingerprint management interface of the APP, selects the permission level (administrator / regular user / visitor) for the fingerprint to be enrolled, and the APP generates a "fingerprint enrollment request command," which is transmitted to the WA8372 flash memory controller chip through the currently connected interface (such as Lightning, TYPE-C, or USB-A). After receiving the command, the WA8372 first verifies the current operation permission (only administrators can initiate the new fingerprint operation). If the verification is successful, it enters the enrollment preparation stage. Then, the WA8372 outputs a high-level signal to the STC89C52 microcontroller via the GPIO instruction line, triggering the STC89C52 to enter "fingerprint control mode." Simultaneously, the WA8372 sends the "fingerprint enrollment" operation command (hexadecimal code, such as 0x01) and the corresponding permission level code (such as administrator 0x01, regular user 0x01) to the STC89C52 via the UART data line. 02) Ensure that the STC89C52 clearly defines the operation type and permission association. After receiving the instruction, the STC89C52 drives the AS608 fingerprint sensor to start acquisition, prompting the user to press their finger on the sensor. The sensor acquires fingerprint images three times. The STC89C52 uses a built-in deduplication algorithm to compare the clarity and completeness of the three images, selecting the image with the clearest feature points and the least interference as the valid acquisition data. This avoids subsequent template generation failures due to blurry single acquisitions. The STC89C52 extracts feature points from the selected valid fingerprint image, extracting 50-80 core feature points from fingerprint ridges, endpoints, bifurcation points, etc., to form the original fingerprint feature data. Subsequently, the original feature data is encrypted using the AES-128 encryption algorithm to prevent the feature data from being tampered with or leaked during storage, ensuring fingerprint information security. The STC89C52 communicates via the I2C interface (SDA=P2.0, SCL=P2).1) The encrypted fingerprint feature data is written to the "fingerprint template area" (480KB capacity, each template occupies 6KB space) of the external AT24C512EEPROM, and the corresponding permission level code is written to the "permission configuration area" (32KB capacity, each permission data occupies 400 bytes), completing the hardware-side data storage. After storage, the STC89C52 sends a "successful enrollment" result (e.g., 0x00) to the WA8372 via the UART data line. The WA8372 then synchronizes the result to the APP, and the APP updates the enrollment status on the fingerprint management interface. The system displays the number of fingerprints (e.g., "9 / 80 sets") and prompts the user to perform subsequent fingerprint verification tests. If no clear fingerprint image is obtained after three attempts, the STC89C52 will report a "Failed to Collect" result, and the app will prompt the user to "clean your finger or adjust your pressing posture and try again." If the AT24C512's storage capacity is insufficient (≥80 used fingerprints), the STC89C52 will report a "Capacity Full" result, and the app will display a pop-up warning: "Fingerprint storage has reached its limit. Please delete unused fingerprints and add new ones." This ensures that the enrollment process clearly prompts the user in abnormal scenarios, improving operational fault tolerance.

[0031] In addition to the existing red and blue LEDs, the lighting control module also has a dedicated green LED for administrators. It is connected to the GPIO pins of WA8372 through a transistor driver circuit, where GPIO2 = red light, GPIO3 = blue light, and GPIO4 = green light, and the transistor model is S8050. The status indicators are as follows: initially, the red light is on; when the administrator successfully verifies, the green light is on; when the regular user successfully verifies, the blue light is on; when the visitor successfully verifies, the blue light flashes once per second; and when verification fails, the red light flashes once per second. The different lights visually distinguish permissions and device status.

[0032] The specific workflow of the aforementioned lighting control module is as follows: When any interface (Lightning, TYPE-C, USB-A) is connected to a terminal device (such as a mobile phone or computer), the WA8372 detects the VBUS5V voltage and initiates initialization. At this time, the red LED remains constantly lit, indicating that the device is in the "initializing, not ready" state. If initialization is successful (e.g., interface protocol matching, normal dual-master communication), the red LED turns off, and the blue LED flashes once (1Hz flashing frequency, lasting 0.5 seconds), indicating that the device is ready and fingerprint operation can be performed. If initialization fails (e.g., interface protocol incompatibility, abnormal hardware connection), the red LED turns off, and the blue LED flashes once (1Hz flashing frequency, lasting 0.5 seconds), indicating that the device is ready and fingerprint operation can be performed. The blue LED switches to a flashing mode of 1 flash per second, and the app pops up a message saying "Device initialization failed, please unplug and replug the interface," guiding the user to troubleshoot the problem. After the user initiates an input request in the app and the administrator's permissions are verified, the blue LED enters a slow flashing mode of 0.5 flashes per second, prompting "Please press the fingerprint sensor." When the AS608 begins its first data acquisition, the blue LED briefly turns off and then lights up again (each acquisition corresponds to one "off-on" switch), until three acquisitions are completed. If all three acquisitions are successful and feature extraction and encrypted storage are normal, the blue LED turns green and stays on for 3 seconds, then returns to the off state. The app will simultaneously display "Fingerprint registration successful"; if the fingerprint acquisition fails (e.g., no clear image is obtained after 3 attempts), the blue LED will stop flashing, and the red LED will flash rapidly 5 times at 0.2 seconds, indicating "Fingerprint acquisition failed, please try again". When the user triggers fingerprint verification (e.g., unlocking the storage partition after connecting to the device), the blue LED will flash at a medium speed at 0.3 seconds, indicating "Verifying fingerprint"; if the verification is successful (matching accuracy ≥ 90%), different colors will be displayed according to the user's permissions: administrator permissions (0x01) correspond to a solid green LED for 2 seconds, and ordinary users (0x02) or visitors (0x03) correspond to a solid blue LED for 2 seconds. The LED then turns off, and the storage partition is unlocked according to permissions. If verification fails (match rate < 90%), the red LED flashes three times rapidly at 0.1 seconds, indicating "fingerprint mismatch," and no partition is unlocked. If the read fingerprint template is damaged (CRC check inconsistency), the red and blue LEDs flash alternately (red 0.5 seconds → blue 0.5 seconds), indicating "fingerprint template damaged, needs to be re-entered." When permission conflicts occur (such as multiple interfaces initiating different permission operations at the same time), or hardware malfunctions (such as AT24C512 storage errors, dual master control communication interruptions), the red, green, and blue LEDs simultaneously turn "0."The LED flashes three times in 2 seconds, then the red LED stays on, indicating "Device malfunction, please disconnect and restart." If the fingerprint storage capacity is close to its limit (≥75 used fingerprints), after each fingerprint operation, the green and blue LEDs flash briefly once simultaneously, and the app simultaneously prompts "Fingerprint storage is almost full, it is recommended to delete unused fingerprints," providing early warning of capacity issues. Afterwards, when the interface is unplugged from the terminal device, the WA8372 detects the disappearance of the VBUS voltage, triggering device hibernation. At this time, all LEDs turn off, indicating that the device has disconnected and entered a low-power state. If data transmission continues during disconnection (e.g., file copying is incomplete), the red LED flashes once every 1 second until data transmission is interrupted or completely disconnected, then turns off, indicating "Data transmission incomplete, forced disconnection may result in data loss."

[0033] Software interaction module: It implements fingerprint management, permission configuration and log recording functions through a four-layer architecture. It includes the APP interaction software module and also implements fingerprint hierarchy, which is divided into administrator level, ordinary user level and visitor level. The APP interactive software module is divided into a UI layer, a permission management layer, a business layer, and a communication layer. The UI layer provides a visual operation interface, including a fingerprint management interface to display the number of fingerprints and permission levels, a permission configuration interface to select permission types and check accessible folders, and an access log interface to view access time and operation type. The UI layer displays different permissions based on the permission level codes transmitted by WA8372. The permission management layer is the core of the APP's interactive software module, featuring three major algorithms: Fingerprint capacity management algorithm: displays the number of used and available fingerprints in real time, and displays a pop-up warning "Capacity is about to be full, please delete unused fingerprints" when approaching the 80-group limit; Permission hierarchy algorithm: divides permissions into three levels: Administrator: full permissions, can add and delete fingerprints, modify partition permissions, and view logs; Regular user: only accesses specified partitions, read and write configurable; Visitor: only reads the visitor partition, write and delete are prohibited, bound by permission level code + partition ID; Access log recording algorithm: records the timestamp + permission level + interface type + operation type for each operation, logs are stored locally and can be exported to Excel, and can only be viewed by the administrator. The business layer optimizes the fingerprint processing flow, while the communication layer has the function of preventing permission data from being tampered with.

[0034] In the above-mentioned APP interactive software module, the specific workflow of the business layer is as follows: S1. Entry process: APP initiates "entry request" → WA8372 forwards to STC89C52 → STC89C52 drives AS608 to collect fingerprints 3 times (the clearest image is selected by deduplication algorithm) → extract 50~80 feature points → encrypt (AES-128) and write to AT24C512 → APP synchronously stores template backup (to avoid template loss due to hardware failure); S2. Verification process: APP initiates "verification request" → AS608 collects the current fingerprint → STC89C52 reads 80 sets of templates in AT24C512 and compares them one by one (matching degree ≥90% is considered successful) → returns "success + permission level code" to WA8372 → WA8372 controls the lights and unlocks the partition; S3: Deletion process (administrator only): APP selects the fingerprint ID to be deleted → sends "delete command" to WA8372 → STC89C52 erases the corresponding template and permission data in AT24C512 → APP updates the number of used fingerprints; The communication layer's workflow is as follows: The communication layer monitors the current device's connected interface type (Lightning, Type-C, USB-A) in real time, and calls the corresponding driver for each interface—the Lightning interface calls the C94MFi certified driver to ensure iOS device compatibility, the Type-C interface calls the IP2721PD protocol driver to match the transmission rate, and the USB-A interface calls the W25Q16JV driver for automatic loading, establishing a stable hardware communication link. Simultaneously, the communication layer implements data encapsulation and format conversion: after receiving instructions from the service layer (such as fingerprint enrollment instruction 0x01), the communication layer processes the data according to hardware conventions. The data is encapsulated in a "frame format" (instruction header 0xAA + instruction content + CRC8 checksum). At the same time, the digital signal from the APP is converted into an electrical signal that the hardware can recognize, avoiding transmission failure due to data format incompatibility. Moreover, the communication layer implements transmission monitoring and feedback forwarding: during data transmission, the communication layer monitors the transmission status in real time. If a signal interruption or checksum failure occurs, a retransmission mechanism is immediately triggered (up to 3 times). After receiving the hardware feedback result (such as operation success 0x00), the frame header and checksum are removed, the core result is converted into a signal that the APP can parse, and forwarded to the business layer for processing, ensuring the accuracy and timeliness of bidirectional data transmission.

[0035] Hardware-software integrated modules: These are the hubs connecting hardware actions and software logic, ensuring seamless functionality. They include multi-interface, fingerprint, permission, and storage linkage interaction modules, as well as exception handling and control modules.

[0036] The multi-interface-fingerprint-permission-storage linkage interaction module includes administrator permission interaction and multi-interface switching interaction. The workflow of administrator permission interaction is as follows: interface access and initialization, APP wake-up and permission detection, fingerprint verification and permission activation, and permission operation and synchronization.

[0037] The workflow for multi-interface switching interaction is as follows: initial connection, new interface access detection and secondary verification and protocol switching, as well as permission maintenance and data access.

[0038] The aforementioned administrator permission interaction needs to be completed through the linkage of the software interaction module, the dual main control collaboration module, and the hardware storage module. The core revolves around "permission verification - operation execution - result feedback". The specific process is as follows: permission triggering and verification start: when the user initiates an operation requiring administrator permission in the APP (such as adding or deleting fingerprints, or modifying partition capacity), the APP UI layer passes the request to the business layer. The business layer generates an "administrator permission verification instruction", which is encapsulated by the communication layer and transmitted to the WA8372 through the current interface (such as TYPE-C). After receiving the instruction, the WA8372 triggers the STC89C52 to enter the "permission verification mode" through the GPIO instruction line, and at the same time sends the "administrator permission verification request" and the current operation identifier (such as 0x03 corresponding to "delete fingerprint") through the UART data line.

[0039] Fingerprint verification and authorization confirmation: The STC89C52 drives the AS608 fingerprint sensor to collect the user's fingerprint, extracts the feature points, and compares them with the administrator fingerprint template (authorization code 0x01 associated template) stored in the "authorization configuration area" of the AT24C512. If the comparison is successful (match rate ≥ 90%), the STC89C52 sends a "authorization verification passed" result (0x00) to the WA8372 via UART and sends the administrator authorization key. If the comparison fails (match rate < 90%), it sends a "verification failed" result (0x01) and controls the red LED to flash 3 times to prompt the user.

[0040] Operation execution and status synchronization: After receiving the "permission verification passed" result, WA8372 unlocks the corresponding operation permission and executes the user request (such as sending a "delete command" to STC89C52 when deleting a specified fingerprint, and STC89C52 deletes the corresponding template and permission data in AT24C512 via I2C); after the operation is completed, WA8372 feeds back the result to the APP business layer through the communication layer, and the business layer updates the UI interface synchronously (such as a "fingerprint deletion successful" pop-up window, a decrease in the number of registered fingerprints), records the operation log (including operation time and administrator identity), and controls the green LED to stay on for 2 seconds to indicate that the operation is completed; The workflow for multi-interface switching and interaction revolves around "interface status monitoring - protocol adaptation - permission synchronization - data connection," requiring the coordinated operation of multi-interface protocol modules, dual-master control collaboration modules, and APP interaction modules. The specific steps are as follows: Interface access monitoring and initial adaptation: The multi-interface protocol module monitors the access status of Lightning, TYPE-C, and USB-A interfaces in real time (such as VBUS voltage detection and device handshake signals). When an interface is connected to a terminal (such as a mobile phone or computer), the corresponding protocol adaptation is immediately initiated. The Lightning interface completes iOS device authentication through the C94MFi chip, the TYPE-C interface identifies the terminal protocol type (such as PD2.0 / 3.0) through the IP2721PD chip, and the USB-A interface automatically loads the corresponding system driver through the W25Q16JV chip to ensure that the interface and the terminal communicate normally initially.

[0041] Permission information synchronization and switching confirmation: After the interface adaptation is completed, the multi-interface protocol module transmits the interface type information to the WA8372. The WA8372 requests the currently stored user permission data (read from the AT24C512 permission configuration area) from the STC89C52 via the UART data line and synchronizes the permission code (0x01 / 0x02 / 0x03) to the APP. After the APP communication layer receives the interface switching signal, it triggers the business layer to update the permission display (such as the UI layer marking "Current TYPE-C interface, administrator permission"), and at the same time pops up a window to prompt the user "Interface has been switched, do you want to continue the current operation?" After the user confirms, the data interaction stage begins.

[0042] Data connection and state maintenance: If there are incomplete data operations (such as file reading, fingerprint verification) before the switch, the WA8372 will temporarily store the current data breakpoint (such as file reading offset, fingerprint verification progress); after the switch, the new interface completes protocol adaptation, and the WA8372 calls the data connection algorithm to transmit the breakpoint information to the terminal through the new interface to ensure seamless operation continuation (such as after switching from USB-A to TYPE-C, files can continue to be read from the breakpoint); at the same time, the multi-interface protocol module synchronously controls the indicator light status (such as the blue LED flashing briefly when the TYPE-C interface is connected, and displaying the corresponding color according to permissions after the switch is completed), and the APP records the interface switch log (including the switch time and the interface types before and after), completing the entire switch interaction process.

[0043] The anomaly handling control module provides solutions for fingerprint template corruption, permission conflicts, and fingerprint capacity issues. When a fingerprint template is corrupted, the STC89C52 checks the CRC code when reading the template; if this fails, an app pop-up is triggered. Recovery from app backup or re-entry is supported, but only administrators can perform this operation. CRC code verification is an error detection technology used to verify data integrity. It uses a specific algorithm to calculate a fixed-length checksum, and then compares the checksum to determine if the data was corrupted during transmission or storage due to interference or errors. In case of permission conflicts, requests are sorted by permission priority and access time, prioritizing higher-priority requests and sending a "partition occupied" warning with a flashing red light to lower-priority devices. To resolve fingerprint capacity issues, a pop-up warning is displayed when ≥75 used fingerprints are available, and a list of fingerprints to be deleted is displayed, sorted by "last used time." Operations are prohibited when only one administrator fingerprint remains to prevent uncontrolled access.

[0044] Fingerprint template corruption: When the anomaly handling control module detects that the fingerprint template is corrupted (the CRC check result is inconsistent with the stored check code when reading the template data in the AT24C512), it immediately sends a "template corruption signal" to the STC89C52; the STC89C52 feeds back to the WA8372 via UART, and then transmits it to the APP through the communication layer; the APP business layer triggers a pop-up window prompting "Fingerprint template corrupted, do you want to restore from backup?" After the user confirms, the APP retrieves the locally backed-up template data, re-encrypts it, and sends it to the AT24C512 for storage; after successful restoration, the module controls the blue LED to flash once, and synchronously updates the APP fingerprint management interface status. If the backup is missing, it prompts "Fingerprint needs to be re-entered"; Permission conflict: When multiple interfaces initiate operations simultaneously (such as Lightning connecting to a mobile phone requesting administrator partition unlocking, or USB-A connecting to a computer requesting ordinary user partition access), the exception handling control module detects a permission conflict and sorts them according to the rule of "interfaces with the same priority, higher-priority operations take precedence"; it suspends low-priority requests and prompts the corresponding terminal APP with "Device busy, current operation has been suspended"; at the same time, it controls the red and blue LEDs to flash alternately (0.5 seconds / time) to remind of the conflict status; after the high-priority operation is completed, the module automatically triggers the low-priority request to retry. If the retry is successful, the indicator light status is restored to normal; if it fails, the user is prompted again. Fingerprint full capacity: When the number of fingerprints stored in the AT24C512 is ≥80 (full capacity), the exception handling control module intercepts the operation when the user initiates a new fingerprint enrollment request and sends a "capacity full" signal to the STC89C52. The STC89C52 informs the WA8372 via UART, and the WA8372 triggers a pop-up warning in the APP: "Fingerprint storage has reached the limit, please delete unused fingerprints." At the same time, the APP interface highlights "80 / 80 used fingerprints." After the user deletes the old fingerprints, the module detects that there is free capacity, removes the enrollment interception, and sends a "enrollment available" signal to the APP. At this time, the user can re-initiate the fingerprint enrollment operation, and the module updates the capacity statistics synchronously.

[0045] The above is the entire working process of the device, and all contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0046] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-interface fingerprint recognition card-type USB flash drive, comprising a hardware core module, a software interaction module, and a hardware-software hybrid module, characterized in that: The core hardware module is the physical foundation of the USB flash drive, responsible for interface adaptation, fingerprint acquisition, data storage, and status indication. The core hardware module includes a multi-interface protocol module, a dual-master control collaboration module, a multi-specification card adapter module, a fingerprint recognition module, and a lighting control module. Software interaction module: It implements fingerprint management, permission configuration and log recording functions through a four-layer architecture. It includes the APP interaction software module and also implements fingerprint hierarchy, which is divided into administrator level, ordinary user level and visitor level. Hardware-software integrated modules: These are the hubs connecting hardware actions and software logic, ensuring seamless functionality. They include multi-interface, fingerprint, permission, and storage linkage interaction modules, as well as exception handling and control modules.

2. The multi-interface fingerprint recognition card-type USB flash drive according to claim 1, characterized in that: The multi-interface protocol module covers three interfaces: Lightning, Type-C, and USB-A, adapting to different terminal devices. The Lightning interface integrates a C94MFi chip and a CH224K chip. The C94MFi chip completes iOS device certification, and the CH224K chip converts the protocol to USB 2.0, supporting Apple mobile phones and tablets. The TYPE-C interface is equipped with an IP2721PD chip, which can detect the protocol type and adjust the transmission rate according to permissions, making it compatible with Android phones and laptops; The USB-A interface integrates a W25Q16JV chip, which automatically loads the driver and has the function of prompting the user's permission scope through a system pop-up window when connected to a computer. The dual-master control collaborative module adopts a flash memory controller chip + microcontroller chip architecture. The flash memory controller chip is model WA8372, and the microcontroller chip is model STC89C52. The STC89C52 serves as the fingerprint control core and connects to an external EEPROM chip via an I2C interface. The external EEPROM chip is model AT24C512 with a capacity of 512KB. At the same time, the STC89C52 drives the AS608 through a circuit connection. The AS608 is a fingerprint recognition module and is a fingerprint recognition chip. The WA8372 serves as the core of flash memory control, communicating with the STC89C52 via GPIO command lines, UART data lines, and permission data transmission lines. It also coordinates storage partition control and lighting adjustment. It has a built-in 1ms timer; if no STC89C52 instruction reception confirmation signal is received within 100ms after the instruction is sent, it will retransmit, up to three times. Permission transmission uses CRC8 checksum to prevent errors. The GPIO instruction line is used to trigger the fingerprint control mode, the UART data line is used to transmit operation instructions and results, and the permission data transmission line is used to transmit permission level codes 0x01, 0x02, and 0x03. Meanwhile, the Lightning, Type-C, and USB-A interfaces are all electrically connected to the WA8372 flash memory controller chip, which coordinates data transmission and access control.

3. A multi-interface fingerprint recognition card-type USB flash drive according to claim 2, characterized in that: The AT24C512 is divided into a fingerprint template area and an access configuration area. The fingerprint template area is 480KB. Each fingerprint template contains feature points and a verification code, occupying 6KB. It stores 50 to 80 encrypted feature points. Each encrypted feature point stores 128 bytes. The 480KB area stores 80 sets. The permission configuration area is 32KB, which stores the permission level and access permissions for each fingerprint group. Each group of permission data occupies 400 bytes, and 32KB stores 80 groups.

4. A multi-interface fingerprint recognition card-type USB flash drive according to claim 1, characterized in that: The multi-specification card adapter module uses a 20-pin compatible slot and a multi-channel analog switch, supporting TF, SD, and CF memory cards. The multi-channel analog switch uses a CD4051 chip. The partitioning logic of the multi-specification card adapter module is as follows: it connects to the peripheral interface of the WA8372. After the WA8372 reads the card capacity, it automatically assigns permissions to associated partitions. The administrator partition has 20% capacity with read and write permissions, the ordinary user partition has 60% capacity with read-only permissions for ordinary users, read and write permissions for administrators, and 20% capacity for guest partitions with read-only permissions for all users. Cross-partition access is prohibited through the "partition selection command".

5. A multi-interface fingerprint recognition card-type USB flash drive according to claim 2, characterized in that: The core of the fingerprint recognition module is a fingerprint recognition chip, model AS608, driven by STC89C52. The fingerprint enrollment process is as follows: during enrollment, fingerprints are collected 3 times, 50-80 feature points are extracted and encrypted and written to AT24C512; during verification, the current fingerprint features are collected and compared with 80 sets of templates in AT24C512 one by one. If the matching degree is ≥90%, it is considered successful, and the result and the permission level code are fed back to WA8372.

6. A multi-interface fingerprint recognition card-type USB flash drive according to claim 1, characterized in that: In addition to the existing red and blue LEDs, the lighting control module also has a dedicated green LED for administrators. It is connected to the GPIO pins of WA8372 through a transistor driver circuit, where GPIO2 = red light, GPIO3 = blue light, and GPIO4 = green light, and the transistor model is S8050. The status indicators are as follows: initially, the red light is on; when the administrator successfully verifies, the green light is on; when the regular user successfully verifies, the blue light is on; when the visitor successfully verifies, the blue light flashes once per second; and when verification fails, the red light flashes once per second. The different lights visually distinguish permissions and device status.

7. A multi-interface fingerprint recognition card-type USB flash drive according to claim 1, characterized in that: The APP interactive software module is divided into a UI layer, a permission management layer, a business layer, and a communication layer. The UI layer provides a visual operation interface, including a fingerprint management interface to display the number of fingerprints entered and the permission level, a permission configuration interface to select permission types and check accessible folders, and an access log interface to view access time and operation type. The UI layer displays information differently based on the permission level codes transmitted by WA8372; The permission management layer is the core of the APP's interactive software module and has three major algorithms. The fingerprint capacity management algorithm displays the number of used and available fingerprints in real time, and when it approaches the limit of 80 sets, a pop-up warning appears saying "The capacity is about to be full, please delete unused fingerprints". Permission hierarchy algorithm: Permissions are divided into three levels: Administrator: Full permissions, can add and delete fingerprints, modify partition permissions, and view logs; Regular user: Only accesses specified partitions, read and write permissions are configurable; Visitors: Read-only visitor partition, write and delete are prohibited, bound by permission level code + partition ID; Access log recording algorithm: Records the timestamp, permission level, interface type, and operation type of each operation. Logs are stored locally and can be exported to Excel. Only administrators can view them. The business layer optimizes the fingerprint processing flow, while the communication layer has the function of preventing permission data from being tampered with.

8. A multi-interface fingerprint recognition card-type USB flash drive according to claim 1, characterized in that: The multi-interface-fingerprint-permission-storage linkage interaction module includes administrator permission interaction and multi-interface switching interaction. The workflow of administrator permission interaction is as follows: interface access and initialization, APP wake-up and permission detection, fingerprint verification and permission activation, and permission operation and synchronization.

9. A multi-interface fingerprint recognition card-type USB flash drive according to claim 8, characterized in that: The workflow of the multi-interface switching interaction is as follows: initial connection, new interface access detection and secondary verification and protocol switching, as well as permission maintenance and data access.

10. A multi-interface fingerprint recognition card-type USB flash drive according to claim 1, characterized in that: The anomaly handling control module provides solutions for situations such as fingerprint template damage, permission conflicts, and full fingerprint capacity. When a fingerprint template is damaged, the STC89C52 checks the CRC code when reading the fingerprint template. If it fails, an APP pop-up window is triggered, supporting restoration from APP backup or re-entry, but only administrators can operate on this. The CRC code is an error detection technology used to verify data integrity. It calculates a fixed-length check code on the data using a specific algorithm, and then compares the check code to determine whether the data has been damaged due to interference, errors, or other problems during transmission and storage. When there is a permission conflict, the system needs to sort the requests by permission priority and access time, prioritize the requests with higher permissions, send a "partition occupied" prompt to the client with lower permissions and flash a red light; when the fingerprint capacity is full, a pop-up warning will be issued when there are ≥75 used fingerprints, and the list of fingerprints to be deleted will be displayed in order of "last used time". Deleting an administrator's fingerprint is prohibited when only one set remains, to prevent loss of control over permissions.

Images