Rail transit engineering BIM component model encryption transmission method and system

Abstract

The application relates to the technical field of digital information transmission, and discloses a rail transit engineering BIM component model encryption transmission method and system, which comprises the following steps: extracting a component identifier and combining a session master key to calculate and generate an encryption sub-key; searching a static word table area to map the identifier into a 16-bit local index and generate a confused local index by performing an exclusive or operation with a current frame 32-bit serial number; splicing the index and random number to generate additional authentication data; encrypting data load and generating an authentication tag based on the additional authentication data; and encapsulating and sending the confused local index, the authentication tag and a ciphertext data block. The application combines synchronous static indexes and communication timing parameters to complete dynamic confusion, eliminates the overhead caused by long text identifier frame-by-frame transmission, avoids the blockage caused by channel packet loss and disorder, and realizes single-frame orthogonal isolation independent authentication decryption.

Description

Technical Field

[0001] This invention relates to a method and system for encrypted transmission of BIM component models in rail transit engineering, belonging to the field of digital information transmission technology. Background Technology

[0002] Currently, in network communication engineering, the mainstream security mechanism adopts a global encrypted encapsulation channel for continuous byte streams. A two-way handshake establishes a unified encrypted session context to achieve full-process ciphertext protection. This streaming cryptographic reassembly mechanism relies on strict alignment of message sequences. When the physical channel experiences sudden packet loss or out-of-order delivery, the receiving end's decryption state machine loses its symmetrical pace and suspends processing subsequent isolated ciphertext frames, relying on the sliding window of the transmission protocol to wait for retransmission. When the network carries a three-dimensional spatial dataset with high concurrency and nonlinear characteristics, the spatial correlation between entities is strong. Traditional continuous byte stream encryption lacks the basic support for implementing independent secure encapsulation of discrete entity data frames, causing local transmission failures in the interaction process of network element nodes to propagate directly upwards, triggering a global channel decryption deadlock. If a long text format entity unique identifier is directly carried in each discrete single-frame message to establish a single-frame verification basis, the redundancy of the physical network header increases several times. When massive entities interact concurrently, the effective payload transmission capacity of the channel is rapidly consumed, forcing the system to make an insurmountable compromise between transmission continuity and fine-grained security binding.

[0003] To address redundancy in protocol header data, conventional approaches tend to physically expand available bandwidth or implement offline static encoding pruning and monotonically increasing numbering conversion. However, physical channel expansion does not change the inherent allocation ratio between header encapsulation and payload. Furthermore, implementing context-independent static pruning in the absence of dynamic transmission session linkage can easily lead to high-frequency global index conflicts in large-scale distributed interaction chains. Moreover, when packet loss occurs due to channel fading, the receiver cannot reconstruct the security verification context from the residual isolated ciphertext frame, creating an inherent conflict between single-frame decoupling and network header overhead that cannot be reconciled through linear thinking. Besides the channel payload bandwidth loss of the physical hardware transmission network, software-controlled communication data encryption and authentication methods also suffer from fundamental flaws when distributing high-density spatial discrete data streams, failing to balance transmission continuity with fine-grained security binding. For example, Chinese invention patent CN114697051B discloses a method, device, and system for secure data transmission, which obtains the security verification context by splicing frame sequence numbers and data segment sequence numbers. The counter is input into the Advanced Encryption Standard (AES) unit to generate a key stream, which is then used to encrypt discrete data segments within the data frame. In case of decryption errors, the fault is limited to a single frame. However, there is a strong time alignment and serial state dependency between the sending and receiving ends for all discrete data segments within the data frame. The sequence numbers of the data segments at both ends are synchronously updated and reset according to the same predetermined rules. The micro-counter synchronization mechanism based on streaming symmetric encryption has a fundamental boundary mismatch when facing the distribution scenario of digital rail transit engineering BIM entity component models with high concurrency and nonlinear characteristics: the BIM spatial dataset experiences local packet loss and out-of-order arrival of frames in the physical channel due to wireless multipath transmission or high-frequency channel fading. The physical loss of intermediate ciphertext segments causes the receiver's dynamic decryption state machine to lose its symmetrical pace, directly causing subsequent global time sequence misalignment and semantic mismatch of the counter. It is impossible to achieve single-frame orthogonal isolation and independent reconstruction within the current frame. Due to the blocking of the sliding window, the decryption context deadlock is triggered, forcing the frequent discarding of all subsequent ciphertexts in the current frame and relying on continuous retransmission requests, which reduces the load throughput efficiency of the digital rail transit bus.

[0004] Therefore, how to eliminate the frame-by-frame dependency of encrypted communication sessions on long-format text identifiers, and compress message encapsulation overhead to avoid physical link blocking and context decryption deadlock under the premise of orthogonal independent decoupling of streaming transmission frames, has become the technical problem to be solved by this invention. Summary of the Invention

[0005] To address the problems in the background art, the technical solution of the present invention is as follows: A method for encrypted transmission of BIM component models in rail transit engineering, comprising the following steps: Step S1: Extract the building information model component identifier corresponding to the model component to be transmitted. Combine the building information model component identifier, the global session master key, and the dynamic session random number to construct a subkey derivation variable. Input the subkey derivation variable into the key derivation function for one-way hash operation to calculate and generate a component encryption subkey that corresponds one-to-one with the building information model component identifier. Step S2: Retrieve the global static mapping table in the static vocabulary cache of the local storage, and map the variable-length text format building information model component identifiers in place to a fixed-length 16-bit unsigned short integer local index; retrieve the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame, and perform a bitwise XOR operation between the 16-bit unsigned short integer local index and the 32-bit frame sequence number to generate an obfuscated local index with dynamic time-varying characteristics; concatenate the 16-bit unsigned short integer local index with a dynamic session random number to generate additional authentication data for integrity verification; Step S3: Retrieve the hardware symmetric encryption algorithm component, use the component encryption subkey as the symmetric key, and use the additional authentication data as the input associated data to encrypt the component data payload corresponding to the building information model component identifier, output the ciphertext data block, and calculate and generate a fixed-length authentication tag based on the additional authentication data; combine and encapsulate the obfuscated local index, the fixed-length authentication tag, and the ciphertext data block into the current underlying network data frame, and send it to the receiving end through the network physical link.

[0006] Preferably, the method further includes step S4: the receiving end receives the current underlying network data frame and reads the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame; performs a reverse bitwise XOR operation on the 32-bit frame sequence number and the obfuscated local index to restore the 16-bit unsigned short integer local index; and uses the 16-bit unsigned short integer local index as the address offset to retrieve the global static mapping table in the static vocabulary cache of the local memory to reconstruct the building information model component identifier.

[0007] Preferably, before step S1, the method further includes: the sending end and the receiving end negotiating the channel layer key through an elliptic curve key exchange protocol to establish a global session master key.

[0008] Preferably, step S1 includes the following sub-steps: Step S11, the sending end extracts the building information model component identifier corresponding to the model component to be transmitted; Step S12, the building information model component identifier, the global session master key, and the dynamic session random number are combined and concatenated to generate a subkey derivation variable; the subkey derivation variable is input into the key derivation function for one-way hash operation to calculate and generate a component encryption subkey that corresponds one-to-one with the building information model component identifier.

[0009] Preferably, step S4 further includes: when the receiving end encounters local ciphertext frame corruption or single frame authentication failure, discarding the current underlying network data frame, continuing to receive the remaining current underlying network data frames in the sliding window without suspending, and sending a retransmission request containing the corresponding 16-bit unsigned short integer local index to the sending end to complete the retransmission recovery at the single frame level.

[0010] Preferably, the storage capacity of the static vocabulary cache area of ​​the local memory is fixed at 64KB, and the 16-bit unsigned short integer local index is reused in place in the reserved field of the transport layer header of the current underlying network data frame. The transport header overhead length occupied by the 16-bit unsigned short integer local index is 2 bytes.

[0011] Preferably, the step S3 of calling the symmetric encryption algorithm includes: the sending end calling the authentication encryption algorithm with additional data in the hardware symmetric encryption algorithm component, using the component encryption subkey as the current frame symmetric key, and using the additional authentication data as the input associated data, encrypting the component data payload corresponding to the building information model component identifier and calculating the integrity verification tag, and outputting the ciphertext data block and the fixed-length authentication tag.

[0012] Preferably, step S4 further includes: when the current underlying network data frame experiences local packet loss due to channel fluctuations or out-of-order arrival due to multipath transmission, the receiving end independently reconstructs the decryption context within the boundary of the current underlying network data frame based on the 32-bit frame sequence number carried in the received current underlying network data frame, thereby completing the temporal adaptive instantaneous synchronization of the decryption context.

[0013] Preferably, the method further includes step S5, whereby after the sending end and the receiving end have completed their respective encrypted transmission or reconstruction, they retrieve the list of component-level differentiated access authorization policies based on the building information model component identifier, perform component-level permission verification on the access request, and restrict unauthorized access to the current component model data.

[0014] A BIM component model encryption transmission system for rail transit engineering, which implements a method for encryption transmission of BIM component models for rail transit engineering, including: The subkey derivation module is used to extract the building information model component identifier corresponding to the model component to be transmitted, and construct the subkey derivation independent variable by combining the building information model component identifier, the global session master key and the dynamic session random number. The subkey derivation independent variable is input into the key derivation function for one-way hash operation to calculate and generate the component encryption subkey that corresponds one-to-one with the building information model component identifier. The index obfuscation module is used to retrieve the global static mapping table in the static vocabulary cache of the local storage, and to map the variable-length text format building information model component identifiers in situ to a fixed-length 16-bit unsigned short integer local index; it retrieves the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame, performs a bitwise XOR operation between the 16-bit unsigned short integer local index and the 32-bit frame sequence number to generate an obfuscated local index with dynamic time-varying characteristics; and it concatenates the 16-bit unsigned short integer local index with a dynamic session random number to generate additional authentication data for integrity verification. The data encryption and encapsulation module is used to call the hardware symmetric encryption algorithm component, use the component encryption subkey as the symmetric key, and use the additional authentication data as the input associated data to encrypt the component data payload corresponding to the building information model component identifier, and output the ciphertext data block and the fixed-length authentication tag; the obfuscated local index, the fixed-length authentication tag and the ciphertext data block are combined and encapsulated into the current underlying network data frame and sent through the network physical link. The decryption and restoration module is used to read the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame after receiving it; perform a reverse bitwise XOR operation on the 32-bit frame sequence number and the obfuscated local index to restore the 16-bit unsigned short integer local index; and use the 16-bit unsigned short integer local index as the address offset to retrieve the global static mapping table in the static vocabulary cache of the local memory to reconstruct the building information model component identifier.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In the encrypted transmission of BIM component models for rail transit engineering, during the communication session establishment phase, a global topology tree outline of the data entity in a single interaction is used to synchronously allocate and fix physical memory space in the dual-end memory and construct a global static mapping table. This converts the highly redundant long text encoding into an unsigned short integer local index, thus reducing the original tens of bytes of message header overhead. This space compression directly offsets the parasitic loss of the transport layer protocol itself, effectively reducing the encapsulation redundancy of the underlying data packets when facing massive concurrent transmission demands, thereby significantly improving the effective payload transmission ratio of the network physical link and enhancing the effective throughput efficiency during data information transmission.

[0016] 2. The transmitting processor reads the short integer local index corresponding to the component to be transmitted from the memory, combines it with the frame sequence number of the current data frame in the transport layer protocol control block through XOR logic modulation, and generates a confused local index with dynamic time-varying characteristics above the network link layer. The concatenation value of the short integer local index and the dynamic session random number is used as the additional authentication data of this frame. This composite interleaving mechanism cuts off the dependence of the encryption and encapsulation process on the original long text string, introduces the inherent time-varying parameters of the transport protocol without increasing processing overhead, destroys the coherent superposition state of the known plaintext in the channel, and prevents malicious replay or known plaintext detection.

[0017] 3. The receiving end network protocol stack reads the frame sequence number from the data frame, demodulates it with the obfuscated local index carried in the payload using inverse XOR logic, restores the short integer local index corresponding to the frame in situ, and uses this local index as the physical address offset to retrieve the static vocabulary cache area of ​​the local memory to reconstruct the corresponding long text component identifier in situ. Since each frame carries independent transport layer timing parameters, in the event of packet loss or out-of-order delivery, the receiving end does not need to interact with the sending end for retransmission to achieve instantaneous alignment of the decryption context. This confines the single-frame authentication and decryption process to the single-frame boundary corresponding to the current local index, avoiding the propagation of differential errors. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the obfuscation and encryption encapsulation process for component identifiers in the Building Information Modeling (BIM) system of this invention. Figure 2 This is a diagram showing the composition of the line control center server and the transmitting and receiving network terminals of the present invention. Figure 3 This is a schematic diagram illustrating the performance characteristic ratio of the local index configuration in this invention.

[0019] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0021] A method for encrypted transmission of BIM component models in rail transit engineering includes the following steps: Step S1: Extract the building information model component identifier corresponding to the model component to be transmitted, combine the building information model component identifier, the global session master key and the dynamic session random number to construct the subkey derivation independent variable, input the subkey derivation independent variable into the key derivation function to perform one-way hash operation, and calculate and generate the component encryption subkey that corresponds one-to-one with the building information model component identifier. Step S2: Retrieve the global static mapping table in the static vocabulary cache of the local storage, and map the variable-length text format building information model component identifiers in place to a fixed-length 16-bit unsigned short integer local index; retrieve the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame, and perform a bitwise XOR operation between the 16-bit unsigned short integer local index and the 32-bit frame sequence number to generate an obfuscated local index with dynamic time-varying characteristics; concatenate the 16-bit unsigned short integer local index with a dynamic session random number to generate additional authentication data for integrity verification; Step S3: Retrieve the hardware symmetric encryption algorithm component, use the component encryption subkey as the symmetric key, and use the additional authentication data as the input associated data to encrypt the component data payload corresponding to the building information model component identifier, output the ciphertext data block, and calculate and generate a fixed-length authentication tag based on the additional authentication data; combine and encapsulate the obfuscated local index, the fixed-length authentication tag, and the ciphertext data block into the current underlying network data frame, and send it to the receiving end through the network physical link.

[0022] Preferably, the method further includes step S4: the receiving end receives the current underlying network data frame and reads the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame; performs a reverse bitwise XOR operation on the 32-bit frame sequence number and the obfuscated local index to restore the 16-bit unsigned short integer local index; and uses the 16-bit unsigned short integer local index as the address offset to retrieve the global static mapping table in the static vocabulary cache of the local memory to reconstruct the building information model component identifier.

[0023] Preferably, before step S1, the method further includes: the sending end and the receiving end negotiating the channel layer key through an elliptic curve key exchange protocol to establish a global session master key.

[0024] Preferably, step S1 includes the following sub-steps: Step S11, the sending end extracts the building information model component identifier corresponding to the model component to be transmitted; Step S12, the building information model component identifier, the global session master key, and the dynamic session random number are combined and concatenated to generate a subkey derivation variable; the subkey derivation variable is input into the key derivation function for one-way hash operation to calculate and generate a component encryption subkey that corresponds one-to-one with the building information model component identifier.

[0025] Preferably, step S4 further includes: when the receiving end encounters local ciphertext frame corruption or single frame authentication failure, discarding the current underlying network data frame, continuing to receive the remaining current underlying network data frames in the sliding window without suspending, and sending a retransmission request containing the corresponding 16-bit unsigned short integer local index to the sending end to complete the single frame level retransmission recovery.

[0026] Preferably, the storage capacity of the static vocabulary cache area of ​​the local memory is fixed at 64KB, and the 16-bit unsigned short integer local index is reused in place in the reserved field of the transport layer header of the current underlying network data frame. The transport header overhead length occupied by the 16-bit unsigned short integer local index is 2 bytes.

[0027] Preferably, the step S3 of calling the symmetric encryption algorithm includes: the sending end calling the authentication encryption algorithm with additional data in the hardware symmetric encryption algorithm component, using the component encryption subkey as the current frame symmetric key, and using the additional authentication data as the input associated data, encrypting the component data payload corresponding to the building information model component identifier and calculating the integrity verification tag, and outputting the ciphertext data block and the fixed-length authentication tag.

[0028] Preferably, step S4 further includes: when the current underlying network data frame experiences local packet loss due to channel fluctuations or out-of-order arrival due to multipath transmission, the receiving end independently reconstructs the decryption context within the boundary of the current underlying network data frame based on the 32-bit frame sequence number carried in the received current underlying network data frame, thereby completing the temporal adaptive instantaneous synchronization of the decryption context.

[0029] Preferably, the method further includes step S5, whereby after the sending end and the receiving end have completed their respective encrypted transmission or reconstruction, they retrieve the list of component-level differentiated access authorization policies based on the building information model component identifier, perform component-level permission verification on the access request, and restrict unauthorized access to the current component model data.

[0030] A BIM component model encryption transmission system for rail transit engineering, which implements a method for encryption transmission of BIM component models for rail transit engineering, including: The subkey derivation module is used to extract the building information model component identifier corresponding to the model component to be transmitted, and construct the subkey derivation independent variable by combining the building information model component identifier, the global session master key and the dynamic session random number. The subkey derivation independent variable is input into the key derivation function for one-way hash operation to calculate and generate the component encryption subkey that corresponds one-to-one with the building information model component identifier. The index obfuscation module is used to retrieve the global static mapping table in the static vocabulary cache of the local storage, and to map the variable-length text format building information model component identifiers in situ to a fixed-length 16-bit unsigned short integer local index; it retrieves the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame, performs a bitwise XOR operation between the 16-bit unsigned short integer local index and the 32-bit frame sequence number to generate an obfuscated local index with dynamic time-varying characteristics; and it concatenates the 16-bit unsigned short integer local index with a dynamic session random number to generate additional authentication data for integrity verification. The data encryption and encapsulation module is used to call the hardware symmetric encryption algorithm component, use the component encryption subkey as the symmetric key, and use the additional authentication data as the input associated data to encrypt the component data payload corresponding to the building information model component identifier, and output the ciphertext data block and the fixed-length authentication tag; the obfuscated local index, the fixed-length authentication tag and the ciphertext data block are combined and encapsulated into the current underlying network data frame and sent through the network physical link. The decryption and restoration module is used to read the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame after receiving it; perform a reverse bitwise XOR operation on the 32-bit frame sequence number and the obfuscated local index to restore the 16-bit unsigned short integer local index; and use the 16-bit unsigned short integer local index as the address offset to retrieve the global static mapping table in the static vocabulary cache of the local memory to reconstruct the building information model component identifier.

[0031] Example 1: In the concurrent distribution scenario of a rail transit engineering network, when high-frequency fading occurs in the wireless physical channel and data packet loss and temporal disorder are caused by multipath transmission, the traditional continuous byte stream encryption transmission mechanism relies on strict alignment of the message sequence. When the network protocol stack encounters partial message corruption, the decryption state machine loses its symmetrical pace and suspends processing of subsequent isolated ciphertext frames. Furthermore, the entire system is suspended due to waiting for protocol sliding window retransmission. At the same time, if variable-length text format building information model component identifiers containing long-level prefix strings are directly carried inside discrete single-frame messages, the redundancy of the protocol header encapsulation of the data packets increases several times over. Furthermore, the distribution of massive amounts of entities during concurrent requests rapidly depletes the channel's effective payload transmission capacity, leading to transmission delays, network system congestion, and decryption context deadlock. During the initialization phase of the communication session between the sender and receiver, the two ends synchronously allocate a fixed 2-byte physical memory space with a total capacity of 64KB as a static vocabulary cache in their respective memories, based on a single interaction of the global topology tree outline of the Building Information Model (BIM). Simultaneously, both processors establish a global static mapping table containing a fixed number of key-value pairs within this physical memory space, mapping variable-length text-format BIM component identifiers in situ to a fixed-length 16-bit unsigned matrix. The short integer local index reduces the original header overhead to 2 bytes, decreasing the encapsulation redundancy of underlying data packets under massive concurrent data transmission conditions, offsetting parasitic losses in the transport layer protocol, improving the effective payload transmission ratio of the network physical link, and increasing the effective throughput efficiency during data transmission. Furthermore, the global static mapping table is implemented using a doubly linked list trie structure in its internal storage. During the initial handshake of a communication session, the sending processor reads all long text component identifiers from the global topology tree outline and allocates unique 16-bit unsigned short integer values, starting from 0 and incrementing sequentially, according to their natural order of appearance in the tree outline. This information is then stored in the static vocabulary cache. In the storage area, each key-value pair consists of a key composed of a variable-length text string and a value composed of a 16-bit unsigned integer. When performing in-situ mapping, the processor inputs the variable-length text format building information model component identifier into the root node of the trie via the high-speed bus. It then uses a character-by-character matching algorithm to search downwards along the tree path. When the corresponding leaf node is hit, it reads the 16-bit unsigned short integer local index pre-bound in the leaf node and writes the 16-bit unsigned short integer local index into the designated register of the current network data frame transmission control block. This converts the variable-length text retrieval into a fixed 2-byte memory base address offset output.

[0032] When performing component-level key derivation and ciphertext frame encapsulation at the sending end, the sending end processor extracts the building information model component identifier corresponding to the model component to be transmitted. It then constructs a subkey derivation independent variable by combining the building information model component identifier, the global session master key, and a dynamic session random number. This subkey derivation independent variable is input into the key derivation function for one-way hashing to generate a component encryption subkey that corresponds one-to-one with the building information model component identifier. Simultaneously, the sending end processor retrieves the global static mapping table from the static vocabulary cache in local memory, mapping the variable-length text format building information model component identifier in-situ to a fixed-length 1-byte mapping table. A 6-bit unsigned short integer local index is used, and the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame is retrieved. A bitwise XOR operation is performed between the 16-bit unsigned short integer local index and the 32-bit frame sequence number to generate a confused local index. This 16-bit unsigned short integer local index is then concatenated with a dynamic session random number to generate additional authentication data for integrity verification. The sending processor retrieves the authentication encryption algorithm with additional data from the hardware symmetric encryption algorithm component, using the component encryption subkey as the current frame symmetric key and the additional authentication data as input associated data to encrypt the component data corresponding to the building information model component identifier. The payload outputs a ciphertext data block and calculates a fixed-length authentication tag based on the additional authentication data. The obfuscation local index, the fixed-length authentication tag, and the ciphertext data block are then combined and encapsulated into a reserved field in the transport layer header of the current underlying network data frame. This is then sent to the receiving end via the network physical link. Specifically, the key derivation function uses the national commercial cryptography No. 3 algorithm. In actual operation, the sending processor converts the variable-length text format building information model component identifier into a binary data stream, and sequentially appends a fixed-length 256-bit global session master key and a fixed-length 32-bit dynamic session random number to the end, thus forming... A continuous bit stream is used as the subkey derivation independent variable. Then, this subkey derivation independent variable is injected as input data into the input buffer of the hardware encryption chip. The hash calculation unit inside the hardware encryption chip performs iterative compression processing of the National Commercial Cryptography No. 3 algorithm. After iterative calculation, the hash calculation unit outputs a one-way hash digest value with a fixed length of 256 bits. The processor extracts the first 128 bits of this one-way hash digest value as the component encryption subkey exclusive to the current model component and temporarily stores it in the high-speed cache of the sending end for use in the data encryption process. This completes the deterministic derivation from the long text identifier to the fixed-length component encryption subkey.

[0033] The receiving network protocol stack receives the current underlying network data frame through the network physical link and reads the 32-bit frame sequence number from the transport layer protocol control block of the current underlying network data frame. It then performs a reverse bitwise XOR operation between the 32-bit frame sequence number and the obfuscation local index to independently reconstruct a 16-bit unsigned short integer local index within the boundaries of the current underlying network data frame. Even if the current underlying network data frame experiences partial packet loss due to channel fluctuations or out-of-order arrival due to multipath transmission, the receiving network protocol stack independently... The receiving processor reconstructs the decryption context and completes its timing adaptive synchronization. Using a 16-bit unsigned short integer local index as the address offset, it retrieves the global static mapping table from the static vocabulary cache in local memory. It then reconstructs the building information model component identifier in situ. Simultaneously, the receiving processor utilizes the locally maintained global session master key, the demodulated 16-bit unsigned short integer local index, and the current dynamic session random number to reproduce the component encryption subkey of the frame in situ through a key derivation function. Finally, it combines the 16-bit unsigned short integer local index with the dynamic session random number. The concatenated values ​​are assembled into additional authentication data, which, along with the fixed-length authentication tag and ciphertext data block within the received frame, are input into the authentication encryption algorithm component with additional data for integrity verification. When the receiving end encounters partial ciphertext frame corruption or single-frame authentication failure, it discards the current underlying network data frame, restricts the differential propagation of errors to subsequent data frames, continues to receive the remaining current underlying network data frames in the sliding window without suspending, and sends a retransmission request containing the corresponding 16-bit unsigned short integer local index to the sending end, completing the single-frame level retransmission recovery. In actual operation, from the receiving end to the sending end... From the moment the sending end sends a retransmission request until the receiving end successfully obtains the corresponding retransmitted ciphertext frame and restores a steady state, the system enters a transitional dead zone phase lasting no more than 50 milliseconds. During this phase, the distribution queue of the receiving end's network protocol stack remains open, and independent verification, decryption, and data in-situ recovery are performed on other independent network data frames that arrive normally afterward. The parsed normal component data is temporarily stored in the receiving end's sliding window ring buffer to ensure that the transmission channel is not suspended or blocked. At the same time, the retransmission state machine built into the receiving end starts a decrementing 50-millisecond timer.If a retransmitted data frame carrying the same 16-bit unsigned short integer local index and passing authentication is received within this 50-millisecond period, the retransmission state machine determines that the system has successfully recovered to a steady state. It then delivers the subsequent normal component data temporarily stored in the circular buffer, along with the retransmitted and recovered component data, to the upper-layer application in the original topology sequence. If the retransmitted frame still hasn't arrived when the timer decrements to 0, the system automatically marks the local index corresponding to that single frame as locally invalid and skips that frame to continue the global session. This provides a reliable engineering deadlock protection under timing jumps and transmission delays. After the sending and receiving ends complete their respective encrypted transmission or reconstruction, they retrieve the component-level differentiated access authorization policy list based on the building information model component identifier. They perform component-level permission verification on access requests to restrict unauthorized access to the current component model data. This allows the digital rail transit network transmission architecture to maintain fine-grained component-level security binding while eliminating the dependency of encrypted communication on carrying long text identifiers frame by frame through the mutual mapping between communication session states and protocol timing control parameters. This gives data frames independent decryption attributes independent of the external session context.

[0034] Example 2: The system utilizes a semi-physical hardware test platform built with a network protocol analyzer and a physical channel simulator to acquire test data. The physical interface of the network test platform has a line-speed throughput specification of 1000Mbps and a hardware delay boundary of less than 0.1ms. Gaussian white noise with a signal-to-noise ratio of 20dB is introduced into the physical link through the channel simulator, and a 50Hz power frequency interference harmonic is simultaneously superimposed to construct a non-ideal operating condition benchmark. Regarding the setting of the core control parameter—the allocation bit width of the static vocabulary buffer—in the verification experiment, parameter identification and influencing factor analysis show that the size of the addressable space is directly controlled by the binary bit width of the local index, and the scale of the number of model component entities directly determines the probability of addressing collisions. Based on this, when determining the parameters, the control unit adjusts the bit width to balance the in-situ transmission overhead of the model component identifiers and the limit constraints of the mobile terminal's memory space. When the number of model component entities is in the hundreds of thousands, to avoid identifier index collisions, if the local index bit width tends towards its lower limit, i.e., 8-bit binary encoding is used, because it can... The addressing space limit is only 256 addressing units. When facing the concurrent distribution of large-scale components, index conflicts occur, which leads to address overwriting during decryption mapping at the receiving end. Conversely, if the local index bit width tends to its upper limit, i.e., using 32-bit binary encoding, although its addressing space is expanded, a single index will occupy 4 bytes of space. This not only causes the memory overhead required by the dual-end global static mapping table to exceed 1024KB, triggering a buffer overflow in the embedded network terminal, but also exceeds the available byte limit in the reserved field of the network transport layer packet header, triggering secondary forced fragmentation and framing of the network layer protocol message, reducing the effective payload transmission ratio of the communication channel. Based on the above-mentioned double-down monotonic constraint relationship between addressing capacity and protocol encapsulation capacity, the method provided by this invention selects a 16-bit unsigned short integer local index as a parameter. At this time, the physical memory space of the corresponding static vocabulary cache is fixed at 64KB. While fully covering the discrete entity uniqueness retrieval requirements in a single distribution session, the protocol header transmission overhead of a single identifier is stably locked within a fixed scalar limit of 2 bytes.

[0035] In the same Gaussian white noise and power frequency harmonic interference environment as described above, a multi-dimensional comparative test system was established, including the sample group of this invention, the control group, and a partially missing control group. The sample group of this invention fully executed the steps of initializing the global static mapping table, converting the variable-length text format building information model component identifier to a 16-bit unsigned short integer local index in situ, and modulating the 16-bit unsigned short integer local index with a 32-bit frame sequence number using a bitwise XOR logic operation to generate an obfuscated local index. The control group used an existing transport layer secure streaming encryption protocol and encapsulated frame by frame. The component identifier string of the building information model is in whole long text format. For the partially missing control group, while maintaining the other encryption steps unchanged, the bitwise XOR operation modulation of the 16-bit unsigned short integer local index and the 32-bit frame sequence number is selectively removed. When the original input long text string containing four level prefixes and with an average length of 48.6 bytes is used as the test data source at the sending end, the sample group of this invention completes the static vocabulary cache retrieval, converts the long text string in place into a unique 2-byte hexadecimal scalar code, and performs a bitwise XOR operation with the current 32-bit frame sequence number. The XOR logical operation generates a confused local index with time-varying discrete characteristics. Under this mechanism, the protocol header redundancy overhead of the sample group of this invention is only a fixed 2.0 bytes, while the control group carries the original text identifier frame by frame, and its average header overhead reaches 48.6 bytes. The sample group of this invention significantly reduces the transport layer header overhead. When the channel simulator sets the packet loss rate parameter to a problem intensity gradient level of 1.0%, 5.0%, and 10.0%, respectively, the test data shows that under a single-frame packet loss interference of 5.0%, due to the loss of symmetrical pacing of the decryption state machine, the control group is frequently triggered due to sliding window blocking. When the global protocol sliding window is suspended, its payload transmission ratio drops from the initial 91.4% to 31.5%, and the average session suspension recovery latency climbs to 1425.6ms. However, the sample of the present invention using the method maintains a stable payload transmission ratio of 94.2% under the same 5.0% packet loss gradient, and the average frame-level retransmission recovery latency is only 12.8ms. This indicates that the single-frame orthogonal isolation decryption mechanism cuts off the differential correlation between different ciphertext frames, eliminates the constraint of channel packet loss on the continuity of the sliding window, and stably maintains the payload throughput efficiency under the condition of wireless physical channel fading interference.

[0036] To verify the reasonable value of the numerical range boundary, the test further examined the performance of the out-of-range control group, which exceeded the parameter window of this invention. When the local index setting was reduced to an 8-bit unsigned integer scalar in a set of out-of-range control groups, as the number of component entities in the test model steadily increased from 100 to 500, the experimental data indicated that at a specific abrupt inflection point where the number of component entities exceeded 256, the index conflict rate of the global static mapping table exhibited a non-linear and drastic jump, changing instantaneously from 0.0% to 38.4%. Due to the conflict, semantic mismatch occurred during the in-situ reconstruction of the receiver address. The final output decryption tag verification failure rate reached 38.4%, causing frequent decryption anomalies and triggering communication deadlocks. In another out-of-range control group, when the local index setting was increased to a 32-bit unsigned long integer scalar, although the address conflict rate remained at 0.0%, the global static mapping table expanded to 1024KB in memory due to each index scalar occupying 4 bytes of space. This triggered frequent memory page replacements in the embedded network actuator. Furthermore, the 32-bit long integer data exceeded the 2-byte reserved field in the header of the underlying network data packet transport layer. The reuse limit forces the system to implement fragmentation and encapsulation above the network link layer. The measured message protocol secondary fragmentation and framing redundancy increases by 24.5%, causing the channel's effective payload transmission ratio to non-linearly decrease from 94.2% to 68.3%. The aforementioned measured data regarding performance saturation, collision escalation inflection points, and fragmentation degradation effects quantitatively and clearly define the boundary range of the parameter window for the 16-bit unsigned short integer local index and the 64KB static vocabulary buffer. This proves that the numerically limited range represents a deterministic engineering optimization fact that balances address space integrity and physical channel encapsulation overhead. Based on multi-dimensional analysis... Compared with the measured performance feedback of the gradient problem strength test, the present invention sample of the method uses a 16-bit unsigned short integer local index to replace the in-situ of the variable-length text format building information model component identifier, combined with a bitwise XOR timing obfuscation mechanism based on the frame sequence number, to stably suppress the message out-of-order impact caused by channel fading, reduce the protocol header redundancy of the digital rail transit transmission network when carrying the distribution of refined components, and maintain the independent recovery capability of the decryption context within the orthogonal isolation boundary of a single frame, so that the entire network protocol stack can maintain a high proportion of effective payload transmission throughput when facing complex interference conditions.

[0037] Example 3: This example combines Figures 1 to 3 This document describes a method and system for encrypted transmission of BIM component models in rail transit engineering. Figure 1As shown, the component identifier of the Building Information Model (BIM) is extracted, and the BIM component identifier is combined with the global session master key to construct the component subkey derived independent variable. The component subkey derived independent variable is hashed to generate the component encryption subkey. The static vocabulary cache is retrieved and the BIM component identifier is mapped to a short integer local index. The short integer local index is XORed to generate a confused local index. Dynamic session random numbers are introduced and concatenated with the short integer local index to generate additional authentication data. The component encryption subkey is used and the additional authentication data is used as input to encrypt the data payload to output a ciphertext data block. A fixed-length authentication tag is generated based on the additional authentication data. Finally, the confused local index, the fixed-length authentication tag, and the ciphertext data block are combined and encapsulated into the underlying network frame for transmission.

[0038] like Figure 2 As shown, the system includes a line control center server, a sending network terminal, and a receiving network terminal. The line control center server is equipped with an offline parsing module and a de-identification and desensitization operator, and is connected to the static vocabulary cache in the sending network terminal and the static vocabulary cache in the receiving network terminal via a memory control bus. The sending network terminal also deploys a network protocol processing chip, a static vocabulary cache, a hardware symmetric encryption algorithm component, and a transport layer protocol control block. The receiving network terminal also deploys a network protocol processing chip, a static vocabulary cache, an authentication encryption algorithm component with additional data, and a sliding window. The network protocol processing chips of the sending network terminal and the receiving network terminal are interconnected through a control channel and a network physical link.

[0039] like Figure 3As shown, the local index configuration bit width boundary, as the core control variable at the underlying level, is discretely configured in the numerical space as 8-bit, 16-bit, and 32-bit widths. The performance characteristic ratio (%), as the performance response indicator of the overall transmission architecture, contains two core dimensions: the global static mapping table addressing conflict rate and the trend of the system payload transmission ratio. These two dimensions exhibit a deterministic mapping relationship as the local index configuration bit width boundary changes. When the local index configuration bit width boundary is 8 bits, the global static mapping table addressing conflict rate shows a high state of 40% on the vertical axis, while the trend of the system payload transmission ratio is affected by semantic mismatch caused by address coverage. The system is constrained and remains in the low-efficiency range of 56%. When the local index configuration bit width boundary is precisely switched to 16 bits, the global static mapping table addressing conflict rate fully converges along the curve and drops to 0%, while the system payload transmission ratio changes simultaneously to the maximum throughput efficiency state of 94%. However, when the local index configuration bit width boundary is further increased to 32 bits, although the global static mapping table addressing conflict rate remains at 0% on the bottom horizontal axis, the system payload transmission ratio changes significantly, falling back to about 68% in terms of parameter response due to exceeding the in-situ multiplexing limit of the underlying network packet transmission layer header and triggering secondary fragmentation and framing of the message protocol.

[0040] Example 4: In the case of concurrent distribution in a multi-topology network of a rail transit automation engineering hub, when the data stream encounters high-frequency signal fading and 5% random packet loss interference due to multipath transmission in the open physical wireless channel, the underlying streaming security encryption channel of the transmission system faces data alignment delay. Based on the conventional underlying protocol, the building information model component data is regarded as a continuous linear byte stream without topological boundaries. This causes the network protocol stack to suspend the processing of all subsequent ciphertext frames when individual ciphertext frames are damaged or arrive out of order due to timing reversal. This leads to a global suspension of the sliding window and protocol deadlock. At the same time, if the building information model component identifier string containing deep multi-level prefixes is directly encapsulated and transmitted frame by frame in the limited network layer single-frame data packets, it will directly cause the underlying protocol header overhead to account for more than 80% of the channel load. This will cause a severe degradation of the data bus throughput and induce network congestion when massive entities are retrieved concurrently at high frequency.

[0041] To compensate for the transmission protocol overhead under the aforementioned non-ideal operating conditions and eliminate state machine synchronization misalignment caused by individual frame corruption, the control unit calls the data structure parsing module to retrieve the current global topology tree outline of the building information model during the initialization phase of establishing a long connection session between the two ends. A physical memory addressing space with a fixed total capacity of 64KB is synchronously allocated in the static vocabulary buffer of the local sending end memory and the receiving end protocol processing chip. The control unit synchronously establishes a global static mapping table containing a fixed number of bit key values ​​within the physical memory addressing space. Through the global static mapping table, the long text format building information model component identifiers are mapped one-to-one into a fixed-length 16-bit unsigned short integer local index, reducing the original header overhead to 2B. This space scalar constraint operation directly offsets the encapsulation overhead of the communication control block itself, ensuring that the system can achieve high-density, high-concurrency distribution without service-specific operations at the network layer and link layer.

[0042] When the transmitting end packages and encapsulates data frames containing component characteristics, the transmitting end processor reads the converted 16-bit unsigned short integer local index corresponding to the model component to be transmitted from a specific data bus in memory, and retrieves the 32-bit frame sequence number of the current network data packet in situ from the underlying protocol control block; it performs a bitwise XOR operation on the high and low bytes of the 16-bit unsigned short integer local index with the low 16 bits of the 32-bit frame sequence number, thereby modulating and generating a dynamically changing and discretely distributed confused local index that changes with the transmission timing; at the same time, the transmitting end processor stores the locally fixed global session master key, the parsed 16-bit unsigned short integer local index, and the current dynamic The dynamic session random number is used as a mandatory causal input and is synchronously introduced into the key derivation function based on a one-way cryptographic hash algorithm for text quantization. This process calculates and generates a component encryption subkey uniquely bound to the current specific building information model component identifier. The sending processor concatenates a 16-bit unsigned short integer local index with the dynamic session random number to form additional authentication data for integrity protection. It then calls the authentication encryption algorithm with additional data in the symmetric encryption operator, using the component encryption subkey as the streaming symmetric key for the current frame. The additional authentication data is used as input associated data to perform ciphertext transformation on the component data payload, generating ciphertext data blocks and a fixed-length authentication tag. The obfuscated local index, fixed-length authentication tag, and ciphertext data block are sequentially filled into the reserved field of the protocol header of the current underlying network data frame and sent to the receiving end via the network physical link. After receiving the current underlying network data frame via the network physical link, the receiving end protocol processing unit performs state recovery and independent verification and decryption within a completely independent single-frame physical boundary. The receiving end processor directly extracts the 32-bit frame sequence number from the header control block of the received frame and performs reverse bitwise XOR logic demodulation with the obfuscated local index carried in the current frame to directly restore the 16-bit unsigned short integer local index specific to the current frame. Thus, even if the channel fluctuates, the local index remains unobfuscated. Even in the event of packet loss or out-of-order arrival, the receiving end can still instantly align with the decryption state machine context in situ based on the timing control relationship carried within a single frame. The receiving end processor uses a 16-bit unsigned short integer local index as the physical reference address offset to directly read the global static mapping table in the local static vocabulary cache, and reconstructs and restores the corresponding complete variable-length text format building information model component identifier in situ. Based on the global session master key, the 16-bit unsigned short integer local index, and the current dynamic session random number, the same component encryption subkey is reproduced in situ through the same key derivation function, and the single-frame integrity verification is completed by combining the fixed-length authentication tag and the ciphertext data block.When local channel interference causes a single-frame tag verification failure, the system discards the current damaged frame in situ and sends a minimum-cost retransmission request to the sender based on the extracted 16-bit unsigned short integer local index. This mechanism ensures that other subsequent network data frames within the sliding window can continue to interact uninterruptedly without suspending the entire transmission channel, thus achieving a synchronized and coordinated improvement in data security binding and the throughput efficiency of the communication physical channel.

[0043] Example 5: When the system faces the on-site environment where a brand-new rail transit line model is initially deployed on the line control center server for the first time, the control unit reads the initial structure file containing the track, station, and power supply topology through the offline parsing module, and calls the de-identification and desensitization operator to perform hash mapping on the long text metadata containing sensitive information about the manufacturer. The cleaned variable-length text format building information model component identifiers are arranged in the topology depth-first traversal order, and each independent physical component is assigned a monotonically increasing code value starting from 0 until the global topology tree outline is completely traversed. The corresponding relationship is injected in place into the static vocabulary cache area with a fixed capacity of 64KB reserved in the network protocol processing chip through the memory control bus, and a global static mapping table with strict correspondence between the two ends is established simultaneously.

[0044] In a dynamic session scenario involving multipath transmission and 5% random packet loss interference, to verify the continuous implementation of the dual-end mapping control logic, the sending processor and the receiving protocol processing unit trigger an online integrity comparison during the session handshake period. The processor retrieves the mapping table checksum scalar stored in the current session control block and compares it with the interface status identifier returned by the receiving end through the control channel to complete the consistency verification. When the accumulated delay disturbance caused by multipath transmission exceeds the preset 12.8ms time control window, the system automatically triggers the incremental state compensation mechanism, and the processor utilizes synchronization maintenance... The bus sends a set of aligned heartbeat packets containing the end boundary address of the current static vocabulary buffer to the other end. The receiving end protocol processing unit corrects the addressing boundary in the local memory in place based on the boundary address in the aligned heartbeat packet, thereby eliminating the state reset deviation caused by channel delay without restarting the encryption session. This enables the receiving end network protocol stack to continuously use the restored 16-bit unsigned short integer local index to accurately address the local static vocabulary buffer and reconstruct the complete long text format building information model component identifier, maintaining the orthogonal isolation and decryption state of data frames in the digital rail transit transmission network under complex environments.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0046] Finally, 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.

Claims

1. A method for encrypted transmission of BIM component models in rail transit engineering, characterized in that, Includes the following steps: Step S1: Extract the building information model component identifier corresponding to the model component to be transmitted, combine the building information model component identifier, the global session master key and the dynamic session random number to construct the subkey derivation independent variable, input the subkey derivation independent variable into the key derivation function to perform one-way hash operation, and calculate and generate the component encryption subkey that corresponds one-to-one with the building information model component identifier. Step S2: Retrieve the global static mapping table in the static vocabulary cache of the local storage, and map the variable-length text format building information model component identifiers in place to a fixed-length 16-bit unsigned short integer local index; retrieve the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame, and perform a bitwise XOR operation between the 16-bit unsigned short integer local index and the 32-bit frame sequence number to generate an obfuscated local index with dynamic time-varying characteristics; concatenate the 16-bit unsigned short integer local index with a dynamic session random number to generate additional authentication data for integrity verification; Step S3: Retrieve the hardware symmetric encryption algorithm component, use the component encryption subkey as the symmetric key, and use the additional authentication data as the input associated data to encrypt the component data payload corresponding to the building information model component identifier, output the ciphertext data block, and calculate and generate a fixed-length authentication tag based on the additional authentication data; combine and encapsulate the obfuscated local index, the fixed-length authentication tag, and the ciphertext data block into the current underlying network data frame, and send it to the receiving end through the network physical link.

2. The method for encrypted transmission of BIM component models in rail transit engineering according to claim 1, characterized in that, The method further includes step S4, whereby the receiving end receives the current underlying network data frame and reads the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame; performs a reverse bitwise XOR operation on the 32-bit frame sequence number and the obfuscated local index to restore the 16-bit unsigned short integer local index; and uses the 16-bit unsigned short integer local index as the address offset to retrieve the global static mapping table in the static vocabulary cache of the local memory to reconstruct the building information model component identifier.

3. The method for encrypted transmission of BIM component models in rail transit engineering according to claim 1, characterized in that, Before step S1, the method further includes: the sending end and the receiving end negotiating the channel layer key through an elliptic curve key exchange protocol to establish a global session master key.

4. The method for encrypted transmission of BIM component models in rail transit engineering according to claim 1, characterized in that, Step S1 includes the following sub-steps: Step S11, the sending end extracts the building information model component identifier corresponding to the model component to be transmitted; Step S12, the building information model component identifier, the global session master key and the dynamic session random number are combined and concatenated to generate the subkey derived independent variable. The subkey derivation variables are input into the key derivation function for one-way hash operation to calculate and generate component encryption subkeys that correspond one-to-one with the component identifiers of the building information model.

5. A method for encrypted transmission of BIM component models in rail transit engineering according to claim 2, characterized in that, Step S4 further includes: when the receiving end encounters local ciphertext frame corruption or single frame authentication failure, discarding the current underlying network data frame, continuing to receive the remaining current underlying network data frames in the sliding window without suspending, and sending a retransmission request containing the corresponding 16-bit unsigned short integer local index to the sending end to complete the retransmission recovery at the single frame level.

6. The method for encrypted transmission of BIM component models in rail transit engineering according to claim 1, characterized in that, The storage capacity of the static vocabulary buffer in the local memory is fixed at 64KB, and the 16-bit unsigned short integer local index is reused in place in the reserved field of the transport layer header of the current underlying network data frame. The transport header overhead length occupied by the 16-bit unsigned short integer local index is 2 bytes.

7. The method for encrypted transmission of BIM component models in rail transit engineering according to claim 1, characterized in that, Step S3, which calls the symmetric encryption algorithm, includes: the sending end calls the authentication encryption algorithm with additional data in the hardware symmetric encryption algorithm component, uses the component encryption subkey as the symmetric key of the current frame, uses the additional authentication data as the input associated data, encrypts the component data payload corresponding to the building information model component identifier, calculates the integrity verification tag, and outputs the ciphertext data block and the fixed-length authentication tag.

8. A method for encrypted transmission of BIM component models in rail transit engineering according to claim 2, characterized in that, Step S4 further includes: when the current underlying network data frame experiences local packet loss due to channel fluctuations or out-of-order arrival due to multipath transmission, the receiving end independently reconstructs the decryption context within the boundary of the current underlying network data frame based on the 32-bit frame sequence number carried in the received current underlying network data frame, thereby completing the temporal adaptive instantaneous synchronization of the decryption context.

9. A method for encrypted transmission of BIM component models in rail transit engineering according to claim 1, characterized in that, The method also includes step S5, whereby after the sending end and the receiving end have completed their respective encrypted transmission or reconstruction, they retrieve the list of component-level differentiated access authorization policies based on the building information model component identifier, perform component-level permission verification on the access request, and restrict unauthorized access to the current component model data.

10. A BIM component model encryption transmission system for rail transit engineering, used to implement the BIM component model encryption transmission method for rail transit engineering as described in claim 1, characterized in that, include: The subkey derivation module is used to extract the building information model component identifier corresponding to the model component to be transmitted, and construct the subkey derivation independent variable by combining the building information model component identifier, the global session master key and the dynamic session random number. The subkey derivation independent variable is input into the key derivation function for one-way hash operation to calculate and generate the component encryption subkey that corresponds one-to-one with the building information model component identifier. The index obfuscation module is used to retrieve the global static mapping table in the static vocabulary cache of the local storage, and to map the variable-length text format building information model component identifiers in situ to a fixed-length 16-bit unsigned short integer local index; it retrieves the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame, performs a bitwise XOR operation between the 16-bit unsigned short integer local index and the 32-bit frame sequence number to generate an obfuscated local index with dynamic time-varying characteristics; and it concatenates the 16-bit unsigned short integer local index with a dynamic session random number to generate additional authentication data for integrity verification. The data encryption and encapsulation module is used to call the hardware symmetric encryption algorithm component, use the component encryption subkey as the symmetric key, and use the additional authentication data as the input associated data to encrypt the component data payload corresponding to the building information model component identifier, and output the ciphertext data block and the fixed-length authentication tag; the obfuscated local index, the fixed-length authentication tag and the ciphertext data block are combined and encapsulated into the current underlying network data frame and sent through the network physical link. The decryption and restoration module is used to read the 32-bit frame sequence number in the transport layer protocol control block of the current underlying network data frame after receiving it; perform a reverse bitwise XOR operation on the 32-bit frame sequence number and the obfuscated local index to restore the 16-bit unsigned short integer local index; and use the 16-bit unsigned short integer local index as the address offset to retrieve the global static mapping table in the static vocabulary cache of the local memory to reconstruct the building information model component identifier.

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