Wireless image transmission method based on private Wi-Fi network secure connection

Abstract

The invention discloses a wireless image transmission method based on private Wi-Fi network secure connection, and relates to the technical field of wireless communication, and the method comprises the steps: firstly, generating and encrypting an original Beacon frame, packaging the encrypted Beacon frame into an access point Action frame, adding an identifier to obtain a first Action frame, and transmitting the first Action frame to a private site through a wireless channel in a broadcast manner, and carrying out the head removal decryption to obtain the original Beacon frame; secondly, an original detection request frame is generated and encrypted to obtain an encrypted detection request frame, the encrypted detection request frame is packaged into a customized private site Action frame, an identifier is added to obtain a second Action frame, the second Action frame is sent to the access point and subjected to header removal processing to obtain the private site Action frame, and finally the original detection request frame is obtained through decryption. According to the method, the invalid encryption and decryption operation process is simplified, and the scanning discovery speed and the system response efficiency are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a wireless image transmission method based on a secure private Wi-Fi network connection. Background Technology

[0002] Wireless image transmission mainly relies on wireless communication technologies such as Wi-Fi to achieve real-time transmission of image data, while combining image processing and encoding / decoding technologies to ensure efficient and stable data transmission.

[0003] A typical Wi-Fi infrastructure communication system has a hotspot where multiple devices need to connect to an access point (AP) to communicate with each other. To allow STAs (Stations) to connect to the AP, the AP often broadcasts a beacon so that STAs can discover and connect. Alternatively, hiding the AP requires STAs to scan for the AP's SSID, and the AP responds to the scan, thus achieving discovery and connection. For wireless image transmission systems, since both the AP and STA are private and do not need to be publicly visible, this typical Wi-Fi approach has several security drawbacks: broadcasting a beacon makes the private network easily exposed; hiding the AP means that once the SSID is known externally, external devices can actively scan and connect to the private AP, compromising security; while typical Wi-Fi encrypts transmitted data, the key negotiation process is not encrypted, making it vulnerable to interference or attacks. Summary of the Invention

[0004] The technical problem solved by this invention is that existing technologies can easily expose private networks by broadcasting Beacon frames; by using a hidden sender, external devices can also actively scan and connect to the private AP, thus affecting security.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A wireless image transmission method based on a secure private Wi-Fi network connection includes: Step S1: The access point is used as the sending end to generate a raw Beacon frame that conforms to the Wi-Fi standard and encrypt it to obtain an encrypted Beacon frame. Step S2: Construct an access point Action frame by encapsulating the encrypted Beacon frame as the payload into the access point Action frame and adding an identifier to obtain the first Action frame. Step S3: Using the private site as the receiving end, the first Action frame is broadcast to the private site via the wireless channel. The private site decrypts the first Action frame by removing the header to obtain the original Beacon frame. Step S4: Generate and encrypt the original probe request frame by sending each private site as the sender to obtain the encrypted probe request frame. Step S5: Construct a private site Action frame by encapsulating the encrypted probe request frame as the payload into the private site Action frame and adding an identifier to obtain the second Action frame. Step S6: Using the access point as the receiving end, the second Action frame is sent to the access point via a single channel. The access point removes the header of the second Action frame to obtain the private site Action frame. The private site Action frame is then decrypted to obtain the original probe request frame.

[0006] As a preferred embodiment of the wireless image transmission method based on a private Wi-Fi network security connection described in this invention, step S1 specifically includes the following sub-steps: Step S11: Obtain the original Beacon frame corresponding to the access point according to the Wi-Fi standard; Step S12: Use the private symmetric key to encrypt the original Beacon frame to obtain an encrypted Beacon frame.

[0007] As a preferred embodiment of the wireless image transmission method based on a private Wi-Fi network security connection described in this invention, step S2 specifically includes the following sub-steps: Step S21: Construct an access point Action frame using the Action frame format; Step S22: Embed an encrypted Beacon frame in the payload of the access point Action frame to obtain the embedded Action frame; Step S23: Insert the OUI identifier into the header position of the embedded Action frame to obtain the first Action frame, which includes a MAC header, an OUI identifier, and an encrypted Beacon frame.

[0008] In a preferred embodiment of the wireless image transmission method based on a private Wi-Fi network security connection described in this invention, step S3 includes the following sub-steps: Step S31: Send the first Action frame to the private site using the wireless channel; Step S32: The private site filters the MAC header and OUI identifier through the Wi-Fi driven listening channel to obtain the first Action frame; Step S33: Decrypt the Payload using the private symmetric key obtained in step S12 to obtain the decrypted original Beacon frame.

[0009] In a preferred embodiment of the wireless image transmission method based on a private Wi-Fi network security connection described in this invention, step S4 includes the following sub-steps: Step S41: Enter the SSID and scan request parameters on the private site to generate the original probe request frame; Step S42: Encrypt the original probe request frame using the private symmetric key to obtain an encrypted probe request frame; The original probe request frame includes the target SSID, scan request parameters, and MAC header.

[0010] In a preferred embodiment of the wireless image transmission method based on a private Wi-Fi network security connection described in this invention, step S5 includes the following sub-steps: Step S51: Construct a private site Action frame using the private site; Step S52: Embed an encrypted probe request frame in the payload of the private site Action frame to obtain the embedded Action frame; Step S53: Insert an OUI identifier into the header position of the embedded Action frame to obtain the second Action frame; The second Action frame includes a MAC header, an OUI identifier, and an encrypted probe request frame.

[0011] In a preferred embodiment of the wireless image transmission method based on a private Wi-Fi network security connection as described in this invention, step S6 specifically includes: The access point is used as the receiving end listening channel to receive all frames. When a standard ProbeRequest frame without an OUI identifier is received, it is discarded without response. When a second Action frame is received, it is processed. Remove the header from the second Action frame to obtain an encrypted Probe Request frame. Decrypt the encrypted Probe Request frame using the private key to obtain the original Probe Request frame.

[0012] In a preferred embodiment of the wireless image transmission method based on a private Wi-Fi network security connection as described in this invention, the processing logic of the private symmetric key is as follows: When exchanging keys between the access point and the private site, the sending end encrypts the original key exchange data packet using the private symmetric key to obtain an encrypted key exchange data packet. The key exchange data packet includes an Authentication frame or any interaction frame in the four-way handshake process. A key exchange Action frame is constructed, and the encrypted key data packet is encapsulated as the payload into the key exchange Action frame. The identifier is added to the frame header to obtain a third Action frame. The sending end sends the third Action frame to the receiving end through a wireless channel. After receiving the third Action frame, the receiving end identifies it as a valid frame by recognizing the identifier, removes the Action frame header to obtain the encrypted key exchange data packet, and decrypts it using the private symmetric key to restore the original key exchange data packet. The key negotiation is then completed according to the standard Wi-Fi protocol process.

[0013] In a preferred embodiment of the wireless image transmission method based on a private Wi-Fi network security connection described in this invention, the processing logic of the key exchange Action frame is as follows: The identifier is the same OUI identifier as the first Action frame and the second Action frame, and the OUI identifier exists in plaintext form in the header of the third Action frame.

[0014] In a preferred embodiment of the wireless image transmission method based on a private Wi-Fi network security connection described in this invention, the processing logic for constructing a private site Action frame using a private site is as follows: The private site uses the Action frame defined by the IEEE 802.11 standard as the basic frame mode, selects the Vendor Specific field as the custom frame, and defines a 3-byte OUI identifier as a unique identifier in the payload. The OUI identifier is an unencrypted plaintext field.

[0015] The beneficial effects of this invention are as follows: By encrypting the standard Beacon management frame as a whole and encapsulating it in a vendor-defined Action frame for broadcasting, the existence and identification information of the network are completely invisible to any external general-purpose device. Simultaneously, the access point silently discards standard Probe Requests and only responds to private site requests that have undergone the same encryption and encapsulation process, thus forming a dual concealment mechanism. Passive broadcasts do not reveal the network information, and active probes do not elicit a response. Even if the network SSID is accidentally leaked, external devices cannot discover or connect to the network through conventional means, fundamentally eliminating the risk of the network being scanned and discovered, and unauthorized access. This provides an invisible communication environment for applications such as drone image transmission and security monitoring. Secondly, this invention constructs an end-to-end, full-process communication security guarantee. Its security strategy not only covers the network discovery phase but also extends to the core key exchange process of connection establishment. The Authentication frame and the key negotiation frame of the four-way handshake are also encrypted and custom-encapsulated to ensure that sensitive interactive information in the entire link establishment process exists in unparseable ciphertext form when transmitted over the air. This effectively resists eavesdropping, replay, or man-in-the-middle attacks targeting the key negotiation process, providing high-strength protection for the entire communication chain from network discovery and connection to data transmission, and greatly improving the overall system's anti-attack capability. This invention achieves a high level of security while also considering system processing efficiency and compatibility. By embedding a plaintext organization-unique identifier in the header of the design frame, the receiving end can quickly identify and filter the system frame at the driver layer or hardware layer without having to attempt to decrypt all captured Action frames. This significantly reduces the burden of invalid encryption and decryption operations and improves scanning discovery speed and system response efficiency. Attached Figure Description

[0016] Figure 1 This is a basic flowchart illustrating a wireless image transmission method based on a private Wi-Fi network security connection, as provided in one embodiment of the present invention. Figure 2 This is a diagram illustrating the encryption process of the original Beacon frame. Figure 3 This is a flowchart of the Beacon frame process from the sending end to the receiving end. Figure 4 A basic flowchart for receiving prob request frames at an access point; Figure 5 Flowchart for sending a private Action frame to a private site; Figure 6 A flowchart for receiving private Action frames for a private site. Detailed Implementation

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] Example, refer to Figure 1 , Figure 5 and Figure 6 A wireless image transmission method based on a secure private Wi-Fi network connection is provided, including: Step S1: The access point is used as the sending end to generate a raw Beacon frame that conforms to the Wi-Fi standard and encrypt it to obtain an encrypted Beacon frame. Step S2: Construct an access point Action frame by encapsulating the encrypted Beacon frame as the payload into the access point Action frame and adding an identifier to obtain the first Action frame. Step S3: Using the private site as the receiving end, the first Action frame is broadcast to the private site via the wireless channel. The private site decrypts the first Action frame by removing the header to obtain the original Beacon frame. Step S4: Generate and encrypt the original probe request frame by sending each private site as the sender to obtain the encrypted probe request frame. Step S5: Construct a private site Action frame by encapsulating the encrypted probe request frame as the payload into the private site Action frame and adding an identifier to obtain the second Action frame. Step S6: Using the access point as the receiving end, the second Action frame is sent to the access point via a single channel. The access point removes the header of the second Action frame to obtain the private site Action frame. The private site Action frame is then decrypted to obtain the original probe request frame.

[0019] By encrypting the standard Beacon management frame and encapsulating it within a vendor-defined Action frame for broadcast, the network's existence and identification information are completely invisible to any external general-purpose devices. Simultaneously, the access point silently discards standard Probe Requests, responding only to private site requests that have undergone the same encryption and encapsulation process. This constitutes a double concealment mechanism: passive broadcasts do not reveal the network's identity, and active probes receive no response. Even if the network SSID is accidentally leaked, external devices cannot discover or connect to the network through conventional means, fundamentally eliminating the risk of the network being scanned and discovered, and unauthorized access. This provides an invisible communication environment for applications such as drone image transmission and security monitoring. Secondly, this invention constructs end-to-end full-process communication security. Its security strategy not only covers the network discovery phase, but also extends to the core key exchange process of connection establishment. The authentication frame and key negotiation frames such as the four-way handshake are also encrypted and custom-encapsulated to ensure that sensitive interactive information in the entire link establishment process exists in unparseable ciphertext form when transmitted in the air. This effectively resists eavesdropping, replay, or man-in-the-middle attacks targeting the key negotiation process, so that the entire communication chain from network discovery and connection to data transmission is highly protected, greatly improving the overall system's anti-attack capability. This invention achieves a high level of security while also considering system processing efficiency and compatibility. By embedding a plaintext organization-unique identifier in the header of the design frame, the receiving end can quickly identify and filter the system frame at the driver layer or hardware layer without having to attempt to decrypt all captured Action frames. This significantly reduces the burden of invalid encryption and decryption operations and improves scanning discovery speed and system response efficiency.

[0020] Step S1 specifically includes the following sub-steps: Step S11: Obtain the original Beacon frame corresponding to the access point according to the Wi-Fi standard; Step S12: Use the private symmetric key to encrypt the original Beacon frame to obtain an encrypted Beacon frame.

[0021] As one embodiment of the present invention, refer to Figure 2 First, the Wi-Fi protocol stack of the access point (AP) constructs a Beacon frame according to the IEEE 802.11 standard. The Beacon frame includes frame control, SSID, BSSID, capability information, supported rates, channel number, timestamp, and beacon interval. Then, the entire content of the Beacon frame is encrypted using a pre-shared private symmetric key. Since the standard Beacon frame is broadcast in plaintext, not encrypting it would directly expose the network's presence and basic information. The purpose of encryption is to transform the Beacon frame content from public to ciphertext, so that even if the frame is intercepted, external devices cannot interpret its content. The entire Beacon frame is encrypted using a pre-registered private symmetric key to generate a Beacon frame; This embodiment primarily addresses the problem of network exposure caused by broadcasting Beacon frames in existing technologies. By encrypting the content of the original Beacon frame, the information value of the original Beacon frame itself is eliminated, preventing the content from being parsed by external devices, avoiding the leakage of network identification information, providing encrypted payloads for subsequent encapsulation, and achieving complete concealment of access point information.

[0022] Step S2 specifically includes the following sub-steps: Step S21: Construct an access point Action frame using the Action frame format; Step S22: Embed an encrypted Beacon frame in the payload of the access point Action frame to obtain the embedded Action frame; Step S23: Insert the OUI identifier into the header position of the embedded Action frame to obtain the first Action frame. The first Action frame includes a MAC header, an OUI identifier, and an encrypted Beacon frame.

[0023] As one embodiment of the present invention, refer to Figure 3 The access point constructs a vendor-defined Action frame. The frame type field of the vendor-defined Action frame is specified as Vendor Specific. The encrypted Beacon frame obtained in step S1 is completely placed into the Payload field of this Action frame. At the same time, a 3-byte unencrypted plaintext field, namely the system's unique OUI identifier (0x00A0C5), is inserted into the frame header of the Action frame (at the beginning of the Vendor Specific Content field). This hides the encrypted Beacon frame within the vendor-defined frame, making it impossible for external devices to identify the type of Beacon frame. The OUI identifier enables fast filtering at the driver layer, solving the problem of rapid identification without decryption, avoiding invalid frames from being sent to the protocol stack, and improving the scanning rate.

[0024] Step S3 includes the following sub-steps: Step S31: Send the first Action frame to the private site using the wireless channel; Step S32: The private site filters the MAC header and OUI identifier through the Wi-Fi driven listening channel to obtain the first Action frame; Step S33: Decrypt the Payload using the private symmetric key obtained in step S12 to obtain the decrypted original Beacon frame.

[0025] In one embodiment of the present invention, the access point broadcasts the first Action frame through the wireless channel. When the Wi-Fi driver layer of the private site is listening to the channel, it will match and filter the frame header and OUI field of all captured frames. When it is identified that the MAC header type is Action frame and the OUI is 0x00A0C5, it is determined to be the first Action frame and uploaded to the upper layer for processing. The upper layer software removes the Action frame header, extracts the encrypted data in the Payload, and then decrypts it with the same private symmetric key to finally restore the original Beacon frame information. In this embodiment, together with step S2, a one-way covert network presence notification mechanism is formed. For external devices, the custom Action frame cannot be recognized by air propagation, while for private sites, an interpretable network information mark is set, which solves the problem of exposure caused by broadcast Beacon frames.

[0026] Step S4 includes the following sub-steps: Step S41: Enter the SSID and scan request parameters on the private site to generate the original probe request frame; Step S42: Encrypt the original probe request frame using the private symmetric key to obtain an encrypted probe request frame; The original probe request frame includes the target SSID, scan request parameters, and MAC header.

[0027] Actively scan for access points (APs), construct a standard Probe Request frame, set the SSID field to the SSID of the target AP, and use a private key to encrypt the entire Probe Request frame with AES-256-GCM to generate an encrypted Probe Request frame. Step S41 is used to construct a Probe Request frame that fully conforms to the IEEE 802.11 standard. The private site generates a Probe Request frame with the target SSID field "Private_Net_123" based on the known private network name. The Probe Request frame contains both scan request parameters and a standard MAC header. The scan request parameters are the list of channels to be scanned and the set of supported rates. The MAC header uses the private site's own MAC address as the source address and the broadcast address or a specific BSSID as the target address. This step is used to generate a standard connection query request for a specific private network.

[0028] Step S42 mainly includes: the private site uses a private symmetric key pre-shared with the access point to perform encryption operations on the Probe Request frame (including all fields such as MAC header and SSID) generated in the entire step S41 to generate a ciphertext, namely the encrypted Probe Request frame. This step is used to convert the standard network probe request into ciphertext, hiding the target network SSID, sender identity (MAC address) and capability set information.

[0029] Step S5 includes the following sub-steps: Step S51: Construct a private site Action frame using the private site; Step S52: Embed an encrypted probe request frame in the payload of the private site Action frame to obtain the embedded Action frame; Step S53: Insert an OUI identifier into the header position of the embedded Action frame to obtain the second Action frame; The second Action frame includes the MAC header, OUI identifier, and encrypted probe request frame.

[0030] The private site protocol stack creates an empty Action frame structure and sets the category field of the empty Action frame to Vendor Specific (value 127), indicating a vendor-defined frame. The encrypted Probe Request frame obtained in step S42 is completely placed into the Payload field of the Action frame created in step S51. At the beginning of the Vendor Specific Content area of ​​the Action frame with the encrypted payload, a 3-byte plaintext OUI identifier is inserted to generate a complete second Action frame. The structure of the second Action frame is: standard MAC header, Action frame header (including Vendor Specific indication), OUI identifier, and encrypted Probe Request ciphertext payload. This solves the key problem of fast identification and filtering. The plaintext OUI is the only basis for legitimate access points to achieve hardware-level fast filtering at the physical layer or driver layer when receiving massive wireless frames.

[0031] Step S6 specifically includes: The access point is used as the receiving end listening channel to receive all frames. When a standard ProbeRequest frame without an OUI identifier is received, it is discarded without response. When a second Action frame is received, it is processed. Remove the header from the second Action frame to obtain an encrypted Probe Request frame. Decrypt the encrypted Probe Request frame using the private key to obtain the original Probe Request frame.

[0032] In this embodiment, refer to Figure 4 For each received frame: If the frame is a standard Probe Request frame without an OUI identifier, the access point's driver or underlying firmware checks and finds that the frame is a standard Management frame and does not contain the OUI identifier agreed upon by this system. The access point silently discards such frames without generating any Probe Response or recording it in the log. If the frame is a second Action frame containing a correct OUI, the access point's hardware filter or driver recognizes the frame as an Action frame and the OUI identifier matches, determining that it is a request from a legitimate private site, and submits this Action frame to the upper-layer protocol stack for further processing. For the second Action frame that is recognized as legitimate, the access point's upper-layer protocol software strips the MAC header and Action frame header, extracts the encrypted Probe Request ciphertext immediately following the OUI identifier, and then the access point decrypts the ciphertext using the same private symmetric key as the private site, which facilitates the conversion from private signaling to standard signaling.

[0033] The processing logic for private symmetric keys is as follows: When exchanging keys between the access point and the private site, the sending end encrypts the original key exchange data packet using the private symmetric key to obtain the encrypted key exchange data packet. The key exchange data packet includes the Authentication frame or any interaction frame in the four-way handshake process. A key exchange Action frame is constructed, encapsulating the encrypted key data packet as the payload into the key exchange Action frame, and adding an identifier to the frame header to obtain the third Action frame. The sending end sends the third Action frame to the receiving end via the wireless channel. After receiving the third Action frame, the receiving end identifies it as a valid frame by recognizing the identifier, removes the Action frame header to obtain the encrypted key exchange data packet, and decrypts it using the private symmetric key to restore the original key exchange data packet. The key negotiation is then completed according to the standard Wi-Fi protocol process.

[0034] In this embodiment, when the access point and the private site need to perform authentication or a four-way handshake, the sender may be either the access point or the private site. After the sender generates a standard EAPOL frame (such as an authentication frame or Msg1-Msg4 for a four-way handshake), it immediately encrypts the entire content of the frame using the same private symmetric key. The sender constructs a new Vendor Specific Action frame with the exact same format as the second Action frame, uses the encrypted key exchange data packet as its payload, and inserts a plaintext OUI identifier (0x00A0C5) into the frame header to form a third Action frame. The sender then unicasts this third Action frame through the wireless channel. The receiver identifies and receives the frame through listening and OUI filtering. The receiver removes the frame header, decrypts the payload with a private symmetric key, restores the original EAPOL frame, and then hands it over to a standard Wi-Fi security subsystem (such as a WPA2 / WPA3 module) for normal authentication and key negotiation calculation, ensuring that the interaction process is not perceived or interfered with bystanders, thus realizing a hierarchical security mechanism.

[0035] The processing logic for the key exchange Action frame is as follows: The identifier is the same OUI identifier as the first Action frame and the second Action frame, and the OUI identifier exists in plaintext in the header of the third Action frame.

[0036] In this embodiment, the identifier used by the third Action frame for encapsulating key exchange data is the same OUI identifier used by the first Action frame for encapsulating Beacon and the second Action frame for encapsulating Probe Request. This gives all security management frames of the entire private network system a unified external characteristic, simplifies the identification logic of access points and private sites, and makes it impossible for attackers to distinguish which stage of the connection these frames are in, thus preventing them from launching attacks on specific stages.

[0037] The processing logic for constructing a private site Action frame using a private site is as follows: The private site uses the Action frame defined by the IEEE 802.11 standard as the basic frame mode, selects the Vendor Specific field as the custom frame, and defines a 3-byte OUI identifier as a unique identifier in the payload. The OUI identifier is an unencrypted plaintext field.

[0038] The IEEE 802.11 standard protocol used in this embodiment explicitly reserves frame types for manufacturer expansion and future function definitions, ensuring maximum compliance and coexistence with existing Wi-Fi devices. It will not interfere with other normal networks and can pass relevant radio frequency certifications, which is beneficial to improving the real-time rate of battery-powered mobile devices and image transmission.

[0039] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0040] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A wireless image transmission method based on a secure private Wi-Fi network connection, characterized in that, include: Step S1: The access point is used as the sending end to generate a raw Beacon frame that conforms to the Wi-Fi standard and encrypt it to obtain an encrypted Beacon frame. Step S2: Construct an access point Action frame by encapsulating the encrypted Beacon frame as the payload into the access point Action frame and adding an identifier to obtain the first Action frame. Step S3: Using the private site as the receiving end, the first Action frame is broadcast to the private site via the wireless channel. The private site decrypts the first Action frame by removing the header to obtain the original Beacon frame. Step S4: Generate and encrypt the original probe request frame by sending each private site as the sender to obtain the encrypted probe request frame. Step S5: Construct a private site Action frame by encapsulating the encrypted probe request frame as the payload into the private site Action frame and adding an identifier to obtain the second Action frame. Step S6: Using the access point as the receiving end, the second Action frame is sent to the access point via a single channel. The access point removes the header of the second Action frame to obtain the private site Action frame. The private site Action frame is then decrypted to obtain the original probe request frame.

2. The wireless image transmission method based on a private Wi-Fi network security connection as described in claim 1, characterized in that, Step S1 specifically includes the following sub-steps: Step S11: Obtain the original Beacon frame corresponding to the access point according to the Wi-Fi standard; Step S12: Use the private symmetric key to encrypt the original Beacon frame to obtain an encrypted Beacon frame.

3. The wireless image transmission method based on a private Wi-Fi network security connection as described in claim 2, characterized in that, Step S2 specifically includes the following sub-steps: Step S21: Construct an access point Action frame using the Action frame format; Step S22: Embed an encrypted Beacon frame in the payload of the access point Action frame to obtain the embedded Action frame; Step S23: Insert the OUI identifier into the header position of the embedded Action frame to obtain the first Action frame, which includes a MAC header, an OUI identifier, and an encrypted Beacon frame.

4. The wireless image transmission method based on a private Wi-Fi network security connection as described in claim 3, characterized in that, Step S3 includes the following sub-steps: Step S31: Send the first Action frame to the private site using the wireless channel; Step S32: The private site filters the MAC header and OUI identifier through the Wi-Fi driven listening channel to obtain the first Action frame; Step S33: Decrypt the Payload using the private symmetric key obtained in step S12 to obtain the decrypted original Beacon frame.

5. The wireless image transmission method based on a private Wi-Fi network security connection as described in claim 4, characterized in that, Step S4 includes the following sub-steps: Step S41: Enter the SSID and scan request parameters on the private site to generate the original probe request frame; Step S42: Encrypt the original probe request frame using the private symmetric key to obtain an encrypted probe request frame; The original probe request frame includes the target SSID, scan request parameters, and MAC header.

6. The wireless image transmission method based on a private Wi-Fi network security connection as described in claim 5, characterized in that, Step S5 includes the following sub-steps: Step S51: Construct a private site Action frame using the private site; Step S52: Embed an encrypted probe request frame in the payload of the private site Action frame to obtain the embedded Action frame; Step S53: Insert an OUI identifier into the header position of the embedded Action frame to obtain the second Action frame; The second Action frame includes a MAC header, an OUI identifier, and an encrypted probe request frame.

7. The wireless image transmission method based on a private Wi-Fi network security connection as described in claim 6, characterized in that, Step S6 specifically includes: The access point is used as the receiving end listening channel to receive all frames. When a standard ProbeRequest frame without an OUI identifier is received, it is discarded without response. When a second Action frame is received, it is processed. Remove the header from the second Action frame to obtain an encrypted Probe Request frame. Decrypt the encrypted Probe Request frame using the private key to obtain the original Probe Request frame.

8. The wireless image transmission method based on a private Wi-Fi network security connection as described in claim 6, characterized in that, The processing logic for the private symmetric key is as follows: When exchanging keys between the access point and the private site, the sending end encrypts the original key exchange data packet using the private symmetric key to obtain an encrypted key exchange data packet, which includes an Authentication frame or any interaction frame in the four-way handshake process. A key exchange Action frame is constructed, and the encrypted key exchange data packet is encapsulated as the payload into the key exchange Action frame. The identifier is added to the frame header to obtain the third Action frame. The sending end sends the third Action frame to the receiving end through the wireless channel. After receiving the third Action frame, the receiving end identifies it as a valid frame by recognizing the identifier, removes the Action frame header to obtain the encrypted key exchange data packet, and decrypts it using the private symmetric key to restore the original key exchange data packet. The key negotiation is then completed according to the standard Wi-Fi protocol process.

9. The wireless image transmission method based on a private Wi-Fi network security connection as described in claim 8, characterized in that, The processing logic for the key exchange Action frame is as follows: The identifier is the same OUI identifier as the first Action frame and the second Action frame, and the OUI identifier exists in plaintext form in the header of the third Action frame.

10. The wireless image transmission method based on a private Wi-Fi network security connection as described in claim 9, characterized in that, The processing logic for constructing a private site Action frame using a private site is as follows: The private site uses the Action frame defined by the IEEE 802.11 standard as the basic frame mode, selects the VendorSpecific field as the custom frame, and defines a 3-byte OUI identifier as a unique identifier in the payload. The OUI identifier is an unencrypted plaintext field.

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