Secure transmission system for passport data

Abstract

The invention relates to the technical field of secure transmission, and discloses a secure transmission system for passport data, which comprises the following steps of: respectively executing NFC (Near Field Communication) normalization and NFD (Non-Forwarding Detection) normalization on an original passport name field to obtain a first byte sequence and a second byte sequence; carrying out remainder operation on the first byte length and the second byte length of the first byte sequence and the second byte sequence to respectively obtain a first remainder and a second remainder and generate an oscillation phase residual code; if it is judged that the first byte length or the second byte length enters a boundary adjacent interval defined by the maximum allowable byte length of the target transmission node and the safety margin, k zero characters are inserted into the tail of the passport name field to form DEP telescopic filling; constructing a node vector corresponding to each target transmission node for each target transmission node based on DEP telescopic filling; node vectors of neighboring target transmission nodes are compared to determine a secure transmission alert for the passport name field.

Description

Technical Field

[0001] The present invention relates to the technical field of secure transmission, and more particularly, to a secure transmission system for passport data. Background Art

[0002] In the digital clearance environment of international aviation, cruise ships, and border crossings, passenger passport data must continuously traverse multiple links, including airline systems, travel agency direct interfaces, customs, and counter-terrorism databases. These links include cloud-based platforms using UTF-8, as well as legacy nodes still using Latin-1, ASCII, or other local encodings. To ensure both real-time performance and compatibility, name fields are often dynamically normalized and truncated by byte length before being forwarded in parallel and encrypted across multiple channels, including cellular, satellite, and VPNs. Even the slightest processing discrepancy at any node could trigger a veto or mis-merge of identities downstream.

[0003] Therefore, the following technical problems exist: The same passenger's name undergoes normalization switching between NFC and NFD along the link, causing the length of the byte sequence to fluctuate in short cycles. When the oscillating length falls exactly within the maximum byte length specified by the protocol, some nodes perform hard pruning on the field. Consequently, two records that appear identical but actually contain different codepoint sequences can merge into one after being downgraded to ASCII, leading to pseudo-identical name conflicts and mismatches between blacklists and whitelists, posing security risks. Summary of the Invention

[0004] The present invention provides a secure transmission system for passport data, which solves the technical problems raised in the background technology.

[0005] The present invention provides a system for secure transmission of passport data, comprising: The field processing module is configured to perform NFC normalization and NFD normalization on the name field of the original passport to obtain a first byte sequence and a second byte sequence; and perform a modulo operation on the first byte length and the second byte length of the first byte sequence and the second byte sequence to obtain a first modulo and a second modulo, respectively, and generate an oscillation phase residual code; a telescopic padding module, configured to, if the first byte length or the second byte length falls within a boundary interval defined by the maximum allowable byte length of the target transmission node and a safety margin, insert k zero-frame characters at the end of the passport name field to form a DEP telescopic padding; A node vector module is used to construct a node vector corresponding to each target transmission node based on DEP telescopic padding; a secure transmission module for comparing node vectors of adjacent target transmission nodes to determine a secure transmission alert for a passport name field; The field tracing module is used to perform field tracing based on the node vector received by the target transmission endpoint to obtain the original passport name field.

[0006] Furthermore, NFC normalization and NFD normalization are performed on the passport name field respectively to obtain a first byte sequence and a second byte sequence, including: Confirm that the passport name field S is a valid Unicode string and is encoded in UTF-8; Apply the NFC normalization function to the passport name field S to obtain the NFC normalization result, re-encode the NFC normalization result into a UTF-8 byte sequence to obtain the first byte sequence, and record the first byte length; Apply the NFD normalization function to the passport name field S to obtain an NFD normalization result, re-encode the NFD normalization result into a UTF-8 byte sequence to obtain a second byte sequence, and record the second byte length.

[0007] Further, performing a modulo operation on the first byte length and the second byte length of the first byte sequence and the second byte sequence to obtain a first modulo and a second modulo, respectively, includes: Step 31, select mutually prime numbers and ; Step 32, based on prime numbers Perform the remainder operation on the first byte length to obtain the first remainder ; Step 33, based on prime numbers Perform the remainder operation on the second byte length to obtain the second remainder .

[0008] Furthermore, the oscillation phase residual code is generated, including: Calculate the minimum binary bit width of the first modulus and the second modulus respectively, obtain the first bit width and the second bit width, and make sure that the sum of the first bit width and the second bit width is ≤ 16, otherwise return to step 31 and reselect the prime numbers that are mutually prime. and , until the sum of the first bit width and the second bit width is ≤ 16; Use the second bit width as the number of left shifts ; Generate the oscillation phase residual code based on the number of left shifts as follows: ; in, Indicates the oscillation phase residual code, Indicates left shift operation, Represents a bitwise OR operation.

[0009] Further, determining whether the first byte length or the second byte length enters a boundary interval defined by a maximum allowable byte length of the target transmission node and a safety margin includes: Read the maximum allowed byte length and safety margin from the configuration table of the target transmission node; The difference between the maximum allowed byte length and the safety margin is used as the lower limit of the boundary; Compare the first byte length and the second byte length with the lower limit respectively. If the first byte length or the second byte length is greater than or equal to the lower limit, mark the first byte length or the second byte length as 1; otherwise, mark it as 0. Perform a bitwise OR operation on the flags of the first byte length and the second byte length to obtain a global boundary risk flag.

[0010] Furthermore, k zero-frame characters are inserted at the end of the passport name field to form a DEP telescopic padding, including: If the global boundary risk flag is equal to 1, the passport name field is at risk of clipping; If the passport name field is at risk of clipping, perform the following steps in order: Selecting the maximum value of the first byte length and the second byte length as the coverage length; Calculate the sum of the maximum allowed byte length and the safety margin, and the difference between the sum and the coverage length to obtain the number k of zero-width characters to be filled; Create k zero-frame characters and insert them at the end of the passport name field to form DEP telescopic padding.

[0011] Furthermore, a node vector corresponding to each target transmission node is constructed based on the DEP telescopic padding, including: The node vector includes: DEP stretch padding, oscillation phase residual code, the number of zero-frame character padding, the number of left shifts, the first bit width, and the second bit width.

[0012] Furthermore, the node vectors of the adjacent target transmission nodes are compared to determine the security transmission alert of the passport name field, including: Get the i-th node vector and i+1-th node vector of the i-th target transmission node and the i+1-th target transmission node. If the i-th node vector and the i+1-th node vector are different, and any of the i-th node vector and the i+1-th node vector exists >0, then output a security transmission alert for the passport name field.

[0013] Furthermore, field tracing is performed based on the node vector received at the target transmission endpoint to obtain the original passport name field, including: In response to the secure transmission alert for the passport name field, do the following: Step 91: If the number of zero-frame characters filled in is greater than 0 and the number of zero-frame characters filled in is less than or equal to the sum of the safety margin and 1, then it is determined that the name field in the original passport is damaged; otherwise, proceed to step 92. Step 92, extracting a second remainder from the oscillation phase residual code based on the second bit width, and extracting a first remainder from the oscillation phase residual code based on the number of left shifts; Step 93: Determine if there are k consecutive zero-frame characters in the DEP expansion padding, then remove the k zero-frame characters to obtain the passport name field to be confirmed; Step 94: Perform NFC normalization and NFD normalization on the passport name field to be confirmed and re-encode it into UTF-8 to obtain a first verification byte length and a second verification byte length; Step 95, based on prime numbers Modulo the length of the first verification byte to obtain the first verification remainder; based on the prime number Modulo the length of the second verification byte to obtain the second verification remainder. If the first verification remainder equals the first remainder and the second verification remainder equals the second remainder, the tracing is successful and the name field in the passport to be confirmed is used as the name field in the original passport; otherwise, the tracing fails. Instead of responding to the secure transmission alert for the passport name field, do the following: Step 96: If it is determined that there are k consecutive zero-frame characters in the DEP expansion padding, the k zero-frame characters are stripped off to obtain the original passport name field.

[0014] The beneficial effects of the present invention are as follows: the normalization oscillation and length clipping boundary collision that may occur in the passport name field in a multi-character set link are jointly modeled, and by introducing the oscillation phase residual code and DEP telescopic filling mechanism, the normalization oscillation and length clipping boundary can be identified in real time in the transmission link, and effective avoidance and precise tracing can be completed without interrupting the normal transmission process; end-to-end consistency control and trusted restoration of the passport name field in complex scenarios such as cross-coding, asynchronous clipping, and multi-node transmission can be achieved, significantly improving the security, compatibility and traceability of passport data in cross-border flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a module diagram of a secure transmission system for passport data according to the present invention. DETAILED DESCRIPTION

[0016] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed solely to enable those skilled in the art to better understand and implement the subject matter described herein, and that the functions and arrangements of the elements discussed may be varied without departing from the scope of this specification. Various examples may omit, substitute, or add various processes or components as needed. In addition, features described with respect to some examples may also be combined in other examples.

[0017] like Figure 1 As shown, a system for secure transmission of passport data, comprising: The field processing module is configured to perform NFC normalization and NFD normalization on the name field of the original passport to obtain a first byte sequence and a second byte sequence; and perform a modulo operation on the first byte length and the second byte length of the first byte sequence and the second byte sequence to obtain a first modulo and a second modulo, respectively, and generate an oscillation phase residual code; a telescopic padding module, configured to, if the first byte length or the second byte length falls within a boundary interval defined by the maximum allowable byte length of the target transmission node and a safety margin, insert k zero-frame characters at the end of the passport name field to form a DEP telescopic padding; A node vector module is used to construct a node vector corresponding to each target transmission node based on DEP telescopic padding; a secure transmission module for comparing node vectors of adjacent target transmission nodes to determine a secure transmission alert for a passport name field; The field tracing module is used to perform field tracing based on the node vector received by the target transmission endpoint to obtain the original passport name field.

[0018] In one embodiment of the present invention, NFC normalization and NFD normalization are performed on the passport name field respectively to obtain a first byte sequence and a second byte sequence, including: Confirm that the passport name field S is a valid Unicode string and is encoded in UTF-8; Before byte-level processing, the input data must be in a legal and predictable encoding format to eliminate subsequent normalization and length statistics errors caused by non-UTF-8 or illegal code points, providing a unified starting point for dual-normalization oscillation detection.

[0019] Apply the NFC normalization function to the passport name field S to obtain the NFC normalization result, re-encode the NFC normalization result into a UTF-8 byte sequence to obtain the first byte sequence, and record the first byte length; Combine all decomposable characters into a single pre-combined form to eliminate code point dispersion variants that may occur in different input links, generate a first byte sequence and record the first byte length, which directly reflects the number of bytes occupied by the first byte sequence; Apply the NFD normalization function to the passport name field S to obtain an NFD normalization result, re-encode the NFD normalization result into a UTF-8 byte sequence to obtain a second byte sequence, and record the second byte length.

[0020] Similarly, the second byte length directly reflects the number of bytes occupied by the second byte sequence.

[0021] In one embodiment of the present invention, performing a modulo operation on a first byte length and a second byte length of a first byte sequence and a second byte sequence to obtain a first modulo and a second modulo, respectively, includes: Step 31, select mutually prime numbers and ; In order to map the two normalized byte lengths into a finite, distinguishable phase space, two coprime modulo prime numbers must be selected. and ; coprime prime numbers and It is ensured that the combined period of the first remainder and the second remainder obtained by respectively taking the remainder of the first byte length and the second byte length is maximized, thereby avoiding that different oscillation modes generate the same residue pair.

[0022] Step 32, based on prime numbers Perform the remainder operation on the first byte length to obtain the first remainder ; By taking the remainder operation, the first byte length that may be greater than the maximum value of the protocol is mapped to 0 to The first remainder between the two is an integer. The first remainder reflects the length of the combined state in the module. Spatial position, when the first byte length spans multiple transmission nodes oscillation When , the first modulus will jump periodically.

[0023] Step 33, based on prime numbers Perform the remainder operation on the second byte length to obtain the second remainder .

[0024] By taking the remainder operation, the second byte length that may be greater than the maximum value of the protocol is mapped to 0 The second remainder between the two is an integer, and the second remainder reflects the length of the combined state in the module Spatial position, when the second byte length spans multiple transmission nodes oscillate , the second modulo will jump periodically.

[0025] In one embodiment of the present invention, generating an oscillating phase residual code includes: Calculate the minimum binary bit width of the first modulus and the second modulus respectively, obtain the first bit width and the second bit width, and make sure that the sum of the first bit width and the second bit width is ≤ 16, otherwise return to step 31 and reselect the prime numbers that are mutually prime. and , until the sum of the first bit width and the second bit width is ≤ 16; Before subsequently concatenating the first and second remainders into the oscillation phase residual code, the minimum number of bits that the first and second remainders can occupy must be determined; otherwise, no overlap can be guaranteed after concatenation, and restoration cannot be performed.

[0026] The first bit width indicates the minimum number of digits in the first modulus in binary, and the second bit width indicates the minimum number of digits in the second modulus in binary.

[0027] To concatenate the first modulus and the second modulus into a 16-bit field, the sum of the first bit width and the second bit width must not exceed 16. If it exceeds, a smaller prime number must be selected to reduce the bit width.

[0028] Ensure that the final generated oscillation phase residual code can be stored in a 16-bit unsigned integer and occupies a fixed two bytes in the hardware or protocol message.

[0029] It should be noted that 16 is the maximum bit width of the residual code agreed upon by the protocol to ensure message compatibility.

[0030] Use the second bit width as the number of left shifts ; When splicing, you need to shift the first remainder to the left bits to make room for the second remainder in the lower bits.

[0031] Generate the oscillation phase residual code based on the number of left shifts as follows: ; in, Indicates the oscillation phase residual code, Represents a left shift operation, Represents a bitwise OR operation.

[0032] The oscillation phase residual code carries the phase information of both the combined state (first remainder) and the decomposed state (second remainder), and its length is fixed to the first bit width and the second bit width being less than or equal to 16 bits.

[0033] In one embodiment of the present invention, determining whether the first byte length or the second byte length enters a boundary interval defined by a maximum allowable byte length of the target transmission node and a safety margin includes: Read the maximum allowed byte length and safety margin from the configuration table of the target transmission node; Different target transmission nodes may have different protocol upper limits and acceptable buffer margins.

[0034] The maximum allowed byte length indicates the upper limit of the maximum number of bytes in the passport name field that the target transmission node (such as border inspection system, airline server, etc.) can accept in its protocol or hardware interface.

[0035] The buffer margin represents the extra byte space reserved to mitigate short-term byte number fluctuations caused by normalized oscillation. When a field is passively or actively filled, it can safely accommodate the sum of the maximum allowed byte length and the buffer margin.

[0036] The difference between the maximum allowed byte length and the safety margin is used as the lower limit of the boundary; To determine the risk of near clipping, it is necessary to distinguish between completely safe areas and dangerous near areas, and use the difference between the maximum allowable byte length and the safety margin as the lower limit of the boundary; the lower limit of the boundary means that the first byte length or the second byte length ≥ the lower limit of the boundary, which is considered to enter the near interval.

[0037] Compare the first byte length and the second byte length with the lower limit respectively. If the first byte length or the second byte length is greater than or equal to the lower limit, mark the first byte length or the second byte length as 1; otherwise, mark it as 0. Boolean flag 1 or 0, indicating whether the NFC and NFD normalized views are in proximity state; If the first byte length or the second byte length reaches or exceeds the lower limit, there is a risk of clipping.

[0038] Perform a bitwise OR operation on the flags of the first byte length and the second byte length to obtain a global boundary risk flag.

[0039] As long as any normalized view is in the proximity state, a fill or alarm should be triggered, without the need for both the NFC and NFD normalized views to be in the proximity state at the same time.

[0040] In one embodiment of the present invention, k zero-frame characters are inserted at the end of the passport name field to form a DEP telescopic padding, including: If the global boundary risk flag is equal to 1, the passport name field is at risk of clipping; Filling is only initiated when the previously generated global boundary risk flag indicates that the length of the pre-assembled state or the decomposed state has entered a near state.

[0041] If the passport name field is at risk of clipping, perform the following steps in order: Selecting the maximum value of the first byte length and the second byte length as the coverage length; In the NFC and NFD normalized views, the side with the larger number of bytes is closest to the clipping threshold. Covering the length can avoid the clipping risk of both states at once.

[0042] Calculate the sum of the maximum allowed byte length and the safety margin, and the difference between the sum and the coverage length to obtain the number k of zero-width characters to be filled; To push the total length of the field away from the dangerous range to the safe range, the number of inserted characters needs to be calculated.

[0043] The padding amount k is used to push the field above the threshold but within the margin interval, eliminating the risk of clipping.

[0044] Create k zero-frame characters and insert them at the end of the passport name field to form DEP telescopic padding.

[0045] Only by inserting a zero-frame character at the end of a field that occupies a byte but not the display width can the byte length be truly changed in the transmission and cropping mechanism without affecting the visual sense.

[0046] In one embodiment of the present invention, constructing a node vector corresponding to each target transmission node based on DEP telescopic padding includes: The node vector includes: DEP stretch padding, oscillation phase residual code, the number of zero-frame character padding, the number of left shifts, the first bit width, and the second bit width.

[0047] In one embodiment of the present invention, comparing node vectors of adjacent target transmission nodes to determine a security transmission alert for a passport name field includes: Get the i-th node vector and i+1-th node vector of the i-th target transmission node and the i+1-th target transmission node. If the i-th node vector and the i+1-th node vector are different, and any of the i-th node vector and the i+1-th node vector exists >0, then output a security transmission alert for the passport name field.

[0048] To determine where the normalized oscillation and DEP scaling padding coupling occurs in the link, the node vectors of the two adjacent hops must be obtained. Changes in the node vectors indicate the occurrence of NFC or NFD normalized view oscillation and DEP scaling padding operations. >0 indicates that the transmission node has over-trimmed the passport name field to avoid risks.

[0049] In one embodiment of the present invention, field tracing is performed based on the node vector received by the target transmission destination to obtain the original passport name field, including: In response to the secure transmission alert for the passport name field, do the following: Step 91: If the number of zero-frame characters filled is greater than 0 and the number of zero-frame characters filled is less than or equal to the sum of the safety margin and 1, then it is determined that the name field in the original passport is damaged; otherwise, proceed to step 92; When the target terminal receives a field with zero-frame character padding at the end and k>0, it is necessary to determine whether the padding is within an acceptable safety margin. By using k>0, it is detected that anti-cropping padding has indeed occurred. Then, k≤(safety margin+1) is used to verify that the padding amount does not exceed the reversible range. Otherwise, the field is deemed to have been abnormally tampered with or damaged.

[0050] Step 92, extracting a second remainder from the oscillation phase residual code based on the second bit width, and extracting a first remainder from the oscillation phase residual code based on the number of left shifts; If there is no abnormal padding, the length residues under two normalized views must be recovered from the oscillation phase residual code to verify whether the field has been accidentally modified in the link; Step 93: Determine if there are k consecutive zero-frame characters in the DEP expansion padding, then remove the k zero-frame characters to obtain the passport name field to be confirmed; After confirming that there is no damage and the remnants have been restored, the trailing padding must be cleared to obtain the passport name field to be confirmed.

[0051] Step 94: Perform NFC normalization and NFD normalization on the passport name field to be confirmed and re-encode it into UTF-8 to obtain a first verification byte length and a second verification byte length; After stripping the padding, the actual byte lengths in both views need to be recalculated to verify whether they are consistent with the original remainder.

[0052] Step 95, based on prime numbers Modulo the length of the first verification byte to obtain the first verification remainder; based on the prime number Modulo the length of the second verification byte to obtain the second verification remainder. If the first verification remainder equals the first remainder and the second verification remainder equals the second remainder, the tracing is successful and the name field in the passport to be confirmed is used as the name field in the original passport; otherwise, the tracing fails. End-to-end consistency checking must accurately compare the recalculated length residual with the residual delivered by the link.

[0053] The same modulo operation as steps 32 and 33 is used to generate the first verification modulo and the second verification modulo, and an equivalence check is performed with the previously restored first modulo and second modulo to confirm that the field has not been changed.

[0054] Instead of responding to the secure transmission alert for the passport name field, do the following: Step 96: If it is determined that there are k consecutive zero-frame characters in the DEP expansion padding, the k zero-frame characters are stripped off to obtain the original passport name field.

[0055] If no secure transmission alert is triggered, the field is restored directly by stripping the padding. This quickly restores the original name field, ensuring a balance between performance and accuracy in common scenarios.

[0056] The above describes the embodiments of this embodiment, but this embodiment is not limited to the above specific implementation methods. The above specific implementation methods are merely illustrative and not restrictive. Ordinary technicians in this field can also make many forms based on the inspiration of this embodiment, all of which are protected by this embodiment.

Claims

1. A secure transmission system for passport data, characterized in that: include: The field processing module is configured to perform NFC normalization and NFD normalization on the name field of the original passport to obtain a first byte sequence and a second byte sequence; and perform a modulo operation on the first byte length and the second byte length of the first byte sequence and the second byte sequence to obtain a first modulo and a second modulo, respectively, and generate an oscillation phase residual code; a telescopic padding module, configured to, if the first byte length or the second byte length falls within a boundary interval defined by the maximum allowable byte length of the target transmission node and a safety margin, insert k zero-frame characters at the end of the passport name field to form a DEP telescopic padding; A node vector module is used to construct a node vector corresponding to each target transmission node based on DEP telescopic padding; a secure transmission module for comparing node vectors of adjacent target transmission nodes to determine a secure transmission alert for a passport name field; The field tracing module is used to perform field tracing based on the node vector received by the target transmission endpoint to obtain the original passport name field.

2. A secure transmission system for passport data according to claim 1, characterized in that: NFC normalization and NFD normalization are performed on the passport name field respectively to obtain a first byte sequence and a second byte sequence, including: Confirm that the passport name field S is a valid Unicode string and is encoded in UTF-8; Apply the NFC normalization function to the passport name field S to obtain the NFC normalization result, re-encode the NFC normalization result into a UTF-8 byte sequence to obtain the first byte sequence, and record the first byte length; Apply the NFD normalization function to the passport name field S to obtain an NFD normalization result, re-encode the NFD normalization result into a UTF-8 byte sequence to obtain a second byte sequence, and record the second byte length.

3. A secure transmission system for passport data according to claim 2, characterized in that: Performing a modulo operation on the first byte length and the second byte length of the first byte sequence and the second byte sequence to obtain a first modulo and a second modulo, respectively, includes: Step 31, select mutually prime numbers and ; Step 32, based on prime numbers Perform the remainder operation on the first byte length to obtain the first remainder ; Step 33, based on prime numbers Perform the remainder operation on the second byte length to obtain the second remainder .

4. A secure transmission system for passport data according to claim 3, characterized in that: Generate oscillation phase residual code, including: Calculate the minimum binary bit width of the first modulus and the second modulus respectively, obtain the first bit width and the second bit width, and make sure that the sum of the first bit width and the second bit width is ≤ 16, otherwise return to step 31 and reselect the prime numbers that are mutually prime. and , until the sum of the first bit width and the second bit width is ≤ 16; Use the second bit width as the number of left shifts ; Generate the oscillation phase residual code based on the number of left shifts as follows: ； in, Indicates the oscillation phase residual code, Indicates left shift operation, Represents a bitwise OR operation.

5. A secure transmission system for passport data according to claim 4, characterized in that: Determining whether the first byte length or the second byte length enters a boundary interval defined by a maximum allowable byte length of the target transmission node and a safety margin includes: Read the maximum allowed byte length and safety margin from the configuration table of the target transmission node; The difference between the maximum allowed byte length and the safety margin is used as the lower limit of the boundary; Compare the first byte length and the second byte length with the lower limit respectively. If the first byte length or the second byte length is greater than or equal to the lower limit, mark the first byte length or the second byte length as 1; otherwise, mark it as 0. Perform a bitwise OR operation on the flags of the first byte length and the second byte length to obtain a global boundary risk flag.

6. A secure transmission system for passport data according to claim 5, characterized in that: Insert k zero-frame characters at the end of the passport name field to form a DEP telescopic padding, consisting of: If the global boundary risk flag is equal to 1, the passport name field is at risk of clipping; If the passport name field is at risk of clipping, perform the following steps in order: Selecting the maximum value of the first byte length and the second byte length as the coverage length; Calculate the sum of the maximum allowed byte length and the safety margin, and the difference between the sum and the coverage length to obtain the number k of zero-width characters to be filled; Create k zero-frame characters and insert them at the end of the passport name field to form DEP telescopic padding.

7. A secure transmission system for passport data according to claim 6, characterized in that: Based on DEP telescoping padding, a node vector corresponding to each target transmission node is constructed, including: The node vector includes: DEP stretch padding, oscillation phase residual code, the number of zero-frame character padding, the number of left shifts, the first bit width, and the second bit width.

8. A secure transmission system for passport data according to claim 7, characterized in that: Compare the node vectors of adjacent target transmission nodes to determine the security transmission alert for the passport name field, including: Get the i-th node vector and i+1-th node vector of the i-th target transmission node and the i+1-th target transmission node. If the i-th node vector and the i+1-th node vector are different, and any of the i-th node vector and the i+1-th node vector exists >0, then output a security transmission alert for the passport name field.

9. A secure transmission system for passport data according to claim 8, characterized in that: Based on the node vector received by the target transmission endpoint, field tracing is performed to obtain the original passport name field, including: In response to the secure transmission alert for the passport name field, do the following: Step 91: If the number of zero-frame characters filled is greater than 0 and the number of zero-frame characters filled is less than or equal to the sum of the safety margin and 1, then it is determined that the name field in the original passport is damaged; otherwise, proceed to step 92; Step 92, extracting a second remainder from the oscillation phase residual code based on the second bit width, and extracting a first remainder from the oscillation phase residual code based on the number of left shifts; Step 93: Determine if there are k consecutive zero-frame characters in the DEP expansion padding, then remove the k zero-frame characters to obtain the passport name field to be confirmed; Step 94: Perform NFC normalization and NFD normalization on the passport name field to be confirmed and re-encode it into UTF-8 to obtain a first verification byte length and a second verification byte length; Step 95, based on prime numbers Modulo the length of the first verification byte to obtain the first verification remainder; based on the prime number Modulo the length of the second verification byte to obtain the second verification remainder. If the first verification remainder equals the first remainder and the second verification remainder equals the second remainder, the tracing is successful and the name field in the passport to be confirmed is used as the name field in the original passport; otherwise, the tracing fails. Instead of responding to the secure transmission alert for the passport name field, do the following: Step 96: If it is determined that there are k consecutive zero-frame characters in the DEP expansion padding, the k zero-frame characters are stripped off to obtain the original passport name field.

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