Cross-domain data transmission method

Abstract

The invention provides a cross-domain data transmission method, which comprises the following steps of: compressing and encrypting a file to be transmitted at a sending end to obtain ciphertext data; segmenting the ciphertext data into a plurality of data fragments, and adding header information containing a fragment sequence number and a total fragment number to each fragment; performing error correction coding on each fragment to generate an enhanced fragment, and coding the enhanced fragment into a two-dimensional code image; carrying out parallel layout and dynamic carousel display on the plurality of two-dimensional code images according to frames; at a receiving end, collecting a video frame containing a two-dimensional code through a camera, and performing parallel identification and decoding to obtain a plurality of fragments; and sorting and recombining the fragments according to the header information of the fragments, and performing integrity verification to restore the original file. According to the invention, under the condition of no network / physical isolation, rapid and reliable transmission of large files is realized; through parallel multi-code and rate adaptation, throughput and robustness are significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of data communication and security technology, and specifically relates to a cross-domain data transmission method. Background Technology

[0002] In scenarios with extremely high requirements for confidentiality and isolation, such as government affairs, finance, military industry, and energy, Ethernet, Wi-Fi, Bluetooth, and serial port links between devices are often prohibited, as is hardware modification. Traditional QR codes are mostly used for short texts, and their capacity and reliability are limited, making them unsuitable for large file transfers.

[0003] Existing publicly available technologies mainly include: large-capacity data transmission based on QR codes (transcoding, encryption, compression, segmentation, QR code generation, pagination / dynamic carousel, receiver identification and reassembly); data transmission based on QR codes (displaying QR codes on terminal screens, camera recognition, and stitching); and dynamic QR code retransmission (retransmission of missing data based on segment sequence numbers). These solutions provide the foundation for this invention, but there is still room for optimization in areas such as rate adaptation, parallel multi-code processing, forward error correction, and security enhancement. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a cross-domain data transmission method, comprising the following steps:

[0005] At the sending end:

[0006] The file to be transmitted is compressed and encrypted to obtain ciphertext data;

[0007] The encrypted data is divided into multiple data fragments, and a header containing fragment number and total number of fragments is added to each fragment.

[0008] Each segment is subjected to error correction coding to generate an enhanced segment, and the enhanced segment is encoded into a QR code image;

[0009] Multiple QR code images are arranged in parallel and dynamically displayed in a carousel, frame by frame.

[0010] At the receiving end:

[0011] The camera captures video frames containing QR codes, which are then identified and decoded in parallel to obtain multiple segments.

[0012] The fragments are sorted and reassembled based on the fragment header information, and integrity checks are performed to restore the original file.

[0013] Furthermore, the generation of the QR code image includes: setting the fault tolerance level of the QR code to at least one of M, Q, and H; the parallel layout displays M ≥ 1 QR code per frame, and M is adaptively adjusted according to the screen resolution of the receiving end and the field of view of the camera.

[0014] Furthermore, the frame rate f of the dynamic carousel is adaptively adjusted according to the parsing rate of the receiving end, so that the parsing rate is not less than twice the playback rate.

[0015] Furthermore, the error correction coding is RS(255,223) or LDPC coding, with a redundancy rate of 5–20%.

[0016] Furthermore, the files to be transmitted are encrypted using AES-GCM or ChaCha20-Poly1305, and an authentication tag is generated for integrity verification.

[0017] Furthermore, the method also includes: maintaining the maximum consecutive fragment sequence number and the missing fragment sequence number at the receiving end, and feeding back to the sending end through sound waves or visible light flashing; the sending end prioritizes replaying the QR code corresponding to the missing fragment based on the feedback.

[0018] Furthermore, the fragment header information also includes session ID, file ID, timestamp, and HMAC, which are used for session synchronization and anti-tampering verification.

[0019] Furthermore, the method also includes inserting keyframes into the QR code sequence, wherein the keyframes contain global metadata for rapid synchronization by newly added receivers.

[0020] Furthermore, the method also includes: performing threshold distribution on the ciphertext data or fragmented data using Shamir secret sharing, so as to recover the original data after collecting a threshold number of sub-secrets.

[0021] Systems for implementing the above methods include:

[0022] The sending module is used for file preprocessing, fragmentation and header encapsulation, QR code generation and layout, carousel control and feedback processing;

[0023] The receiver module is used for frame acquisition, parallel decoding, sliding window reconstruction, integrity verification, and file restoration.

[0024] An optional feedback module is available to provide feedback on missing fragment numbers via sound waves or visible light.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] This invention enables fast and reliable transmission of large files even without network / physical isolation; it significantly improves throughput and robustness through parallel multi-code and rate adaptation; it reduces the impact of frame loss / occlusion through automatic retransmission and redundant frames; it enhances security and compliance through encryption / signature / secret sharing; and it adapts to different screens / cameras and environmental changes, with low deployment costs and high ease of use. Attached Figure Description

[0027] Figure 1 This is a system architecture diagram (sender, receiver, optional feedback channel);

[0028] Figure 2 A schematic diagram of data slicing and header encapsulation (magic word, session ID, file ID, slice sequence number, total number of slices, and verification information);

[0029] Figure 3 A schematic diagram of QR code frame layout and carousel (parallel multiple codes, keyframes, repetitive / misaligned display);

[0030] Figure 4 The flowchart for the receiving end sliding window reassembly process (maximum consecutive fragment sequence number, missing interval, retransmission trigger);

[0031] Figure 5 This is a timing diagram for acoustic wave feedback and retransmission (reporting missing sequence numbers and prioritizing replay). Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] This application proposes a cross-domain data transmission method and system, including:

[0034] I. Core Ideas

[0035] The file to be transmitted is compressed, encrypted, and sliced. A QR code is generated for each slice and displayed through screen pagination / dynamic carousel. The receiving end recognizes multiple codes in parallel, reassembles them in order, and verifies their integrity. Automatic retransmission is triggered when necessary.

[0036] II. System Composition

[0037] Sending end: File reading, preprocessing (compression / encryption), slicing and header encapsulation, QR code generation and layout / carousel control, ACK / NACK (optional), logging and status management.

[0038] Receiver: Video frame acquisition, QR code detection and decoding, sliding window reconstruction, missing data analysis and retransmission request (optional), decryption and decompression, integrity verification and disk writing.

[0039] Optional feedback channels: sound waves / audio or visible light flashing are used for missing sequence number feedback, enabling rapid retransmission in unidirectional, highly isolated scenarios.

[0040] III. Key Technologies

[0041] Data slicing and header design (including magic text, session ID, file ID, slice sequence number, total number of slices, verification information, timestamp, etc.).

[0042] Parallel multi-bitrate and rate-adaptive (dynamically adjusts the number of bits per frame and playback rate based on the parsing rate / frame rate).

[0043] Redundancy and error correction (QR code fault tolerance level, duplicate / misaligned frames, RS / Reed-Solomon or LDPC cascaded FEC).

[0044] Security mechanisms (symmetric / asymmetric encryption, HMAC / digital signature, optional Shamir secret sharing threshold distribution).

[0045] Automatic retransmission (error location and rearrangement based on the maximum consecutive fragment sequence number and the missing fragment sequence number). QoS monitoring (frame loss rate, ambiguity estimation, bitrate / frame rate adaptation, code block size adaptation).

[0046] IV. This method specifically includes the following steps:

[0047] Sending process

[0048] 1. Step S101: File reading and metadata generation

[0049] Input: File F to be uploaded, metadata (filename, size, type, creation time, etc.);

[0050] Output: File ID (e.g., UUID), Session ID, Version Number.

[0051] 2. Preprocessing in step S102

[0052] Compression: Prioritize LZ4 (high throughput) or Zstandard (high compression ratio) to output compressed byte stream C;

[0053] Encryption: AES-GCM or ChaCha20-Poly1305 is used to generate ciphertext E and authentication tag T; KDF can be used to derive the session key.

[0054] 3. Step S103: Slicing and Header Packaging

[0055] Set the target code block size B (initially recommended 800–1100 bytes, matching the QR code capacity and fault tolerance level), and calculate the total number of fragments.

[0056] Generate a header H_i for each slice i:

[0057] Magic word (2B), version (1B), session ID (16B), file ID (16B), i (4B), N (4B), data length L_i (2B), timestamp (8B), HMAC (optional, 16B).

[0058] Generate the load P_i = H_i||E_i. If necessary, perform FEC encoding on P_i to obtain P′_i (e.g., RS(255,223)).

[0059] 4. Step S104: QR code generation and layout

[0060] Encoding: Encode P′_i using Base64 or Raw Byte to generate a QR code Q_i (fault tolerance level M / Q / H adjustable);

[0061] Layout: Each frame can display M≥1 QR codes in parallel (such as 2×2, 3×3 grids), and M and frame rate f are adaptively adjusted according to screen resolution / refresh rate and camera field of view;

[0062] Carousel: Carousel Qi in sequence by session ID, supports repeated / misaligned display to improve recognition robustness; keyframes (containing global metadata) can be inserted to facilitate quick synchronization of newly added receivers.

[0063] 5. Step S105 Feedback and Retransmission (Optional)

[0064] If an audio / optical feedback channel is available, the receiver sends the maximum consecutive fragment number and the missing fragment number via sound waves or flashing frequency; the sender then prioritizes replaying the missing fragments accordingly.

[0065] If there is no feedback channel, redundant frames and replay windows are used to cover the missing information.

[0066] Receiver process

[0067] 1. Step R101: Frame Acquisition and Preprocessing

[0068] Video frames are captured and subjected to grayscale conversion, histogram equalization, noise reduction, binarization, and perspective correction to improve the success rate of QR code detection.

[0069] 2. Step R102 Parallel Detection and Decoding

[0070] Use a multi-instance decoder to detect M QR codes in each frame in parallel, and output (i, P′_i) or (i, empty).

[0071] 3. Step R103: Reorganize the sliding window.

[0072] Maintain the receive window W = [R_low, R_high], initially R_low = 0;

[0073] For each successfully decoded i:

[0074] If i == R_low, then submit continuously to the application layer and increment R_low;

[0075] Otherwise, cache it in a hash table indexed by sequence number, triggering a missing range record.

[0076] 4. Step R104 Integrity Verification and Reassembly

[0077] When R_low == N: Submit the reorganization completion event; perform HMAC / signature verification and decompression / decryption, outputting file F′;

[0078] If the verification fails: trigger a partial retransmission or full retransmission strategy.

[0079] 5. Step R105 Feedback and Retransmission (Optional)

[0080] The system uses acoustic / optical feedback to determine the maximum consecutive fragment number and the missing fragment number; if there is no feedback, it relies on redundant frames and replay.

[0081] V. The key parameters and default values ​​of this invention include:

[0082] Initial block size B: 800–1100 bytes recommended (matching the QR code capacity and fault tolerance level);

[0083] Bits per frame (M): 4–9 recommended (depending on screen resolution and camera field of view);

[0084] Frame rate f: 15–30fps recommended (with a trade-off between resolution and motion blur);

[0085] Fault tolerance level: Default M / Q, increased to H for low light / motion scenes;

[0086] FEC: Optional RS(255,223) or LDPC, redundancy 5–20%;

[0087] Encryption: Default AES-GCM, 256-bit key; Signature optional Ed25519;

[0088] Feedback: Sound wave priority (anti-blocking), light flicker as alternative.

[0089] VI. The effectiveness of this application is verified by referring to some embodiments:

[0090] Example 1: One-way import from intranet server

[0091] Scenario: An external laptop imports a 500MB log package to a physically isolated internal server.

[0092] Configuration: B=1024B, M=6, f=20fps, fault tolerance Q, FEC10%, AES-GCM.

[0093] Results: Transmission was completed in approximately 6–8 minutes with a frame loss rate of <1%, and automatic retransmission was completed in 2 rounds.

[0094] Example 2: Unidirectional Strong Isolation (No Backhaul)

[0095] Scenario: A high-density terminal sends a 10MB instruction packet unilaterally to a low-density terminal.

[0096] Configuration: B=900B, M=4, f=15fps, fault tolerance H, FEC15%, Shamir(2,3) secret sharing.

[0097] Results: The process took approximately 3 minutes, and the recognition was stable when the size of a single QR code was less than 1100 bytes; acoustic feedback improved the efficiency of missing code localization.

[0098] Example 3: Quick sharing between mobile devices

[0099] Scenario: Phone A shares a 200MB video with Phone B.

[0100] Configuration: B=800B, M=9, f=30fps, fault tolerance Q, FEC5%, ChaCha20-Poly1305.

[0101] Result: Completed in approximately 4–5 minutes, supporting rapid synchronization of newly added receivers via keyframes.

[0102] In summary, these are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent changes and modifications made in accordance with the scope of the present invention and the contents of the specification are within the scope of the present invention.

Claims

1. A cross-domain data transmission method, characterized in that, Includes the following steps, At the sending end: The file to be transmitted is compressed and encrypted to obtain ciphertext data; The encrypted data is divided into multiple data fragments, and a header containing fragment number and total number of fragments is added to each fragment. Each segment is subjected to error correction coding to generate an enhanced segment, and the enhanced segment is encoded into a QR code image; Multiple QR code images are arranged in parallel and dynamically displayed in a carousel, frame by frame. At the receiving end: The camera captures video frames containing QR codes, which are then identified and decoded in parallel to obtain multiple segments. The fragments are sorted and reassembled based on the fragment header information, and integrity checks are performed to restore the original file.

2. The method according to claim 1, characterized in that, The generation of the QR code image includes: setting the fault tolerance level of the QR code to at least one of M, Q, and H; the parallel layout is to display M ≥ 1 QR code per frame, and M is adaptively adjusted according to the screen resolution of the receiving end and the field of view of the camera.

3. The method according to claim 1, characterized in that, The frame rate f of the dynamic carousel is adaptively adjusted according to the parsing rate of the receiving end, so that the parsing rate is not less than twice the playback rate.

4. The method according to claim 1, characterized in that, The error correction coding is RS(255,223) or LDPC coding, with a redundancy rate of 5–20%.

5. The method according to claim 1, characterized in that: The files to be transmitted are encrypted using AES-GCM or ChaCha20-Poly1305, and an authentication tag is generated for integrity verification.

6. The method according to claim 1, characterized in that, The method further includes: maintaining the maximum consecutive fragment sequence number and the missing fragment sequence number at the receiving end, and feeding back to the sending end through sound waves or visible light flashing; the sending end prioritizes replaying the QR code corresponding to the missing fragment based on the feedback.

7. The method according to claim 1, characterized in that, The fragment header information also includes session ID, file ID, timestamp, and HMAC, which are used for session synchronization and anti-tampering verification.

8. The method according to claim 1, characterized in that, The method further includes inserting keyframes into the QR code sequence, wherein the keyframes contain global metadata for rapid synchronization by newly added receivers.

9. The method according to claim 1, characterized in that, The method further includes: using Shamir secret sharing to perform threshold distribution on the ciphertext data or fragmented data, so as to recover the original data after collecting a threshold number of sub-secrets.

10. A system for implementing the method according to any one of claims 1–9, characterized in that, include: The sending module is used for file preprocessing, fragmentation and header encapsulation, QR code generation and layout, carousel control and feedback processing; The receiver module is used for frame acquisition, parallel decoding, sliding window reconstruction, integrity verification, and file restoration. An optional feedback module is available to provide feedback on missing fragment numbers via sound waves or visible light.

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