High-security instant messaging method and system

Abstract

The invention discloses a high-safety instant messaging method and system, and relates to the technical field of instant messaging. The deep defense system is formed through cooperation of four steps, a decentration foundation is laid, and topology analysis is resisted; 2, session confidentiality is guaranteed, and forward confidentiality is achieved; step 3, crushing metadata values to defend associated attacks; 4, disturbing traffic characteristics, and thoroughly hiding a communication mode; the overall scheme provided by the invention reaches reliable standards in three dimensions of efficiency, security and robustness, not only can ensure high availability and anti-review capability of communication in a decentralized network environment, but also can provide end-to-end privacy and security protection in multiple dimensions of an application layer, a key layer, a metadata layer and a traffic layer; and the high-security instant messaging method is accurately corresponding and realized.

Description

Technical Field

[0001] The present invention relates to the field of instant messaging technology, and in particular to a high-security instant messaging method and system. Background Art

[0002] Instant Messaging (IM) is a web-based synchronous communication method that allows two or more people to exchange multimedia information such as text, voice, video, and files with extremely low latency. Its core value lies in real-time and interactivity. It has not only changed people's communication habits, but also profoundly influenced various scenarios such as personal social interaction, enterprise collaboration, secure communication, and emergency response. From the initial text chat to today's comprehensive platform integrating voice calls, video conferencing, file sharing, and encryption protection, IM has become an indispensable infrastructure and productivity tool in modern society.

[0003] Even when existing instant messaging messages are encrypted, metadata about both communicating parties (such as their identities, communication time, frequency, and packet size) can still be collected by network service providers, push services, or intermediaries. Traffic analysis can then be used to infer sensitive information such as users' social graphs and activity habits. Numerous studies have shown that existing secure communication tools do not fully protect metadata (for example, analyzing communication frequency and time can pinpoint close relationships or business partnership networks, and the metadata of just 200 messages can accurately predict a user's personality traits). Therefore, to address the risks of metadata leakage and traffic analysis in existing instant messaging, a highly secure instant messaging method and system are provided. Summary of the Invention

[0004] The main purpose of the present invention is to provide a highly secure instant messaging method and system to overcome the problems mentioned in the above background technology.

[0005] To achieve the above object, according to one aspect of the present invention, a highly secure instant messaging method is provided, comprising the following method:

[0006] Step 1: When communication is initiated, a probe packet is sent to an online node to measure the node's round-trip delay. If the round-trip delay is lower than a preset threshold, the node is marked as an available node. The performance parameters of the available nodes are obtained, including round-trip delay, available bandwidth, packet loss rate, and observation coefficient. The performance parameters are comprehensively calculated and analyzed to obtain a node performance value. If the node performance value is greater than the preset performance threshold, it is recorded as a candidate node, and each candidate node is screened to form a peer-to-peer connection pool.

[0007] Step 2: Before the two communicating parties formally exchange information, they negotiate an end-to-end temporary key.

[0008] Step 3: Encapsulate the metadata into a transmission data block. Adaptively generate the number of fragments n and the recovery threshold k for the transmission data block, and then fragment the transmission data block into n fragments. Then, intelligently select storage nodes, and each storage node receives one fragment for storage. The transmission data block can only be restored when at least k fragments are obtained simultaneously.

[0009] Step 4: Monitor the traffic status of the two communicating parties during the communication process and determine whether there is a traffic analysis threat. If so, execute the enhanced perturbation mode; otherwise, execute the basic perturbation mode.

[0010] Furthermore, the process of determining whether there is a traffic analysis threat during the communication process is as follows:

[0011] At the communication end, the instant initiator / receiver records the byte length sequence U of m outgoing / incoming packets, where U = {u1, u2, u3...u m}, i=1,2,3..., i is the index, u i = the byte length of the i-th outgoing / incoming packet; calculate the Shannon entropy of the packet size and the packet interval variance; if the Shannon entropy is less than the preset entropy or the packet interval variance is less than the preset variance, then determine that a traffic analysis threat exists; if the Shannon entropy is greater than or equal to the preset entropy and the packet interval variance is greater than or equal to the preset variance, then determine that no traffic analysis threat exists;

[0012] The basic perturbation mode is based on the preset initial parameters and randomly selects any u i The specific initial parameters include the empty packet rate p0, Poisson rate λ0, and time slot length T0.

[0013] Furthermore, the enhanced disturbance mode is:

[0014] 1-6, parameter amplification and time slot adjustment:

[0015] Set the amplification factor of the empty packet rate, the amplification factor of the Poisson rate, the amplification factor of the time slot length and the minimum time slot threshold, and accordingly amplify the empty packet rate p0 and the Poisson rate λ0 in the basic perturbation mode in proportion to obtain the multiplied empty packet rate p dummy , doubling the Poisson rate λ dummy At the same time, the time slot length T0 under the basic perturbation mode is shortened to obtain the shortened time slot length T solt , and multiply the empty packet rate p dummy , doubling the Poisson rate λ dummy and shorten the time slot length T solt Denoted as the strengthening parameter;

[0016] 1-7, empty package sizes vary:

[0017] The number of real messages is counted in real time. After a fixed number of real messages, a very bad empty packet is forcibly sent. The size of the very bad empty packet is the difference between the maximum and minimum byte lengths in the byte length sequence U. The sizes of the remaining empty packets follow a distribution, with a byte length randomly selected from the byte length sequence U. A ±30% jitter is randomly added to each proposed empty packet size.

[0018] 1-8, Sending timing enhancement:

[0019] When shortening the time slot length T solt In the case of multiplying the empty package rate p dummy Make a judgment, randomly select the byte length for each time slot to make an empty packet and send it, and shorten the time slot length T solt A random delay is performed internally; if the real message interval exceeds the preset interval threshold, there is no need to wait for the next time slot and Poisson perturbation is directly entered; if no real traffic is detected for a fixed number of consecutive times within any time slot length, the Poisson rate λ is temporarily multiplied dummy Then multiply it by the Poisson rate amplification factor to launch a round of empty package burst;

[0020] 1-9, monitoring disturbance effects:

[0021] In the enhanced mode, the Shannon entropy of packet length and the variance of packet interval are continuously calculated until both are restored to the point where the enhanced perturbation mode is not triggered, and the system is degraded back to the basic perturbation mode.

[0022] 1-10, constraints:

[0023] If the delay between the two parties is greater than the preset delay or the packet loss rate is greater than the preset packet loss rate, the amplification factor is automatically reduced and T is extended according to the preset degradation rate δ. solt ; The maximum empty message size shall not exceed 20% of the total bandwidth.

[0024] Furthermore, the process of comprehensive calculation and analysis of performance parameters is as follows:

[0025] Extract the performance parameters of available nodes, including round-trip delay, available bandwidth, packet loss rate, and observation coefficient, and record them as RTT, BW, L, and G respectively;

[0026] The round-trip delay, available bandwidth and packet loss rate are normalized respectively. The normalization formula is: RTT max , BW max and L max They are the maximum allowable round-trip delay, the peak bandwidth of the desirable network, and the maximum allowable packet loss rate set by the technicians; the normalized round-trip delay S RTT , available broadband S BW and packet loss rate SL The value obtained by weighted fusion calculation is multiplied by the observation coefficient to obtain the node performance value.

[0027] Furthermore, the key negotiation process is as follows:

[0028] 5-1: Before communication, both parties generate and hold a pair of ECC identity keys. The receiving end also generates a pair of signature pre-keys and a set of one-time pre-keys. After the initiator obtains the other party's public key, it generates a one-time temporary key.

[0029] 5-2: During communication, the initiator sends a negotiation request to the receiver, constructs a negotiation request packet, and sends it to the receiver via secure transmission. The receiver verifies the request and, upon successful verification, sends an empty packet to the initiator or directly enters the local key calculation phase, without any additional return delay.

[0030] 5-3: The communicating parties generate a session key based on the same operation. After the communication ends, both parties immediately destroy the session key to ensure forward secrecy.

[0031] Furthermore, the ECC identity key generation process is:

[0032] Before the two communicating parties formally exchange any information, the initiator generates and holds the ECC key pair for a long time. in Used for signature and DH calculation private key, Used for public identity authentication; the receiving end generates and holds an ECC key pair in the same way The receiving end generates a one-time-use ECC key pair with a certain lifespan. And signed with the long-term private key: The receiving end will The signature σ is uploaded to the decentralized storage; the receiving end generates several pairs of extremely short-period ECC keys in batches i=1,2,3……, i is the index; each pair is used only once and is directly removed from the list after use to prevent replay.

[0033] Furthermore, the metadata encapsulation and adaptive sharding process is as follows:

[0034] The IDs of both parties, message timestamp, message length, message type and other fields are collectively referred to as metadata, and are encapsulated into a binary string denoted as M; the session key K is extracted. sess , randomly generate an initialization vector N, randomly select a plaintext field in the metadata as additional authentication data and record it as AD; call the standard AES-GCM encryption function and output the ciphertext C and authentication tag T GCM Specifically:

[0035] Where C is the encrypted output of the same length as M, T GCM It is a message authentication tag used to verify that the ciphertext and additional authentication data have not been tampered with; (N, C, T GCM ) are serially encapsulated into a transmission data block E, E = N‖‖C‖‖T GCM ;

[0036] Extract the transmission data block length l and set the minimum fragmentation density α min With the maximum fragment density α max and the minimum recovery threshold β min and the maximum recovery threshold β max , according to the formula Calculate the number of fragments n, where σ(l) is a normalized function of the transmission data block length l, specifically: Lmax represents the maximum reference data length, and its unit is the same as l, in bytes; according to the formula Calculate the recovery threshold k;

[0037] Randomly select coefficients a1, a2, a3...a k-1 , construct a polynomial in the large prime field: f(x)=E+a1x+a2x 2 +a3x 3 ...+a j x j ...a k-1 x k-1 , calculate (j,f(j)) according to the number of shards n, and get n shards, where j is the index of any shard.

[0038] Furthermore, the process of intelligently selecting nodes for storage is as follows:

[0039] Extract the logs of each node in real time and extract the number of received shard requests, the number of successful shard writes, the single storage latency of each storage, the number of shards provided, the number of successful shard reconstructions, and the single response latency of each reconstruction. Divide the number of successful shard writes by the number of received shard requests and multiply by 100 to get the storage success rate. Then divide the number of successful shard reconstructions by the number of shards provided to get the reconstruction success rate.

[0040] The box analysis method is used to analyze the single storage delay and single reconstruction delay respectively to obtain the storage delay value and reconstruction delay value;

[0041] The storage success rate h1, reconstruction success rate h2, storage delay value Y1 and reconstruction delay value Y2 are calculated according to the formula Perform normalization and weighted fusion calculation to obtain the observation coefficient G of each node, and update the observation coefficient to step 1 in real time;

[0042] All online nodes are sorted from largest to smallest according to their observation coefficients, and online nodes with a coefficient less than the minimum observation threshold are removed. A fixed number of online nodes at the top level are retained as preferred nodes for shard storage, and an observation interval is set. Preferred nodes with coefficients greater than the upper limit of the observation interval are assigned to the primary storage pool, preferred nodes within the observation interval are assigned to the secondary storage pool, and preferred nodes with coefficients less than the lower limit of the observation interval are assigned to the backup storage pool. The primary storage pool is used to store shards of b1, the secondary storage pool is used to store shards of b2, and the backup storage pool is used to store shards of b3, where b1>b2>b3>0 and b1+b2+b3=1. Shards are randomly assigned within the storage pools of the same level. Each node only stores its assigned shard (j, f(j)) and re-encrypts it locally with the session key. When restoring, fragments can be retrieved from any node layer, totaling k copies.

[0043] When each node receives a request to receive a shard, the number of received shard requests increases by one. If the write is successful, the number of successful shard writes increases by one, and the single storage delay is recorded. At the same time, if a request to provide a shard is received, the number of provided shards increases by one. If the reconstruction is successful, the number of successful shard reconstructions increases by one, and the single reconstruction delay is recorded. The log of each node is updated according to the shard storage and reconstruction operations of each node.

[0044] Furthermore, the box analysis method is:

[0045] Extract the single storage latency of each shard write operation and sort the single storage latency in ascending order to ensure that the format is a one-dimensional numerical sequence. Find the value at the 25th percentile position as the lower quartile Q1, the value at the 50th percentile position as the median Q2, and the value at the 75th percentile position as the upper quartile Q3. Subtract the lower quartile from the upper quartile to get the IOR. Take the minimum value greater than or equal to (Q1-1.5×IOR) among all the sorted values ​​as the lower whisker, and take the maximum value less than or equal to (Q3+1.5×IOR) among all the sorted values ​​as the upper whisker, i.e., the whisker top. Points outside the range of the upper and lower whiskers are considered outliers.

[0046] Input the single storage latency of each shard write operation into the "Box Plot" function and set the parameters to display outliers and horizontal or vertical directions. The box automatically draws a box plot with Q1, Q2, Q3, upper whisker, and lower whisker positions, and marks the outliers separately. Draw a thick line at the median position and mark Q2. Mark Q1 and Q3 at the edge of the box. Optionally display the IQR and whisker top values ​​outside the box.

[0047] Q2, Q3 and the above must be weighted and fused to obtain the storage delay value; similarly, the above box analysis method is performed on the reconstruction single delay of each reconstruction to output the reconstruction delay value.

[0048] In order to achieve the above object, according to another aspect of the present invention, a highly secure instant messaging system is provided, comprising:

[0049] The client includes an initiator and a receiver. The client has a built-in key management module and a communication perturbation module. The key management module performs end-to-end temporary key negotiation management for the client before the client officially communicates. The communication perturbation module monitors the client's traffic status during the communication process and determines whether there is a traffic analysis threat. If so, it executes the enhanced perturbation mode; otherwise, it executes the basic perturbation mode.

[0050] The decentralized network has a built-in connection pool management module and a shard storage module. When the client initiates communication, the connection pool management module sends a probe packet to the online node to measure the round-trip delay of the node. If the round-trip delay is lower than the preset threshold, the node is marked as an available node. The performance parameters of the available nodes are obtained, including round-trip delay, available bandwidth, packet loss rate and observation coefficient. The performance parameters are comprehensively calculated and analyzed to obtain the node performance value. If the node performance value is greater than the preset performance threshold, it is recorded as a candidate node, and each candidate node is screened out to form a peer-to-peer connection pool. The shard storage module encapsulates metadata into a transmission data block, adaptively generates the number of shards n and the recovery threshold k for the transmission data block, and shards the transmission data block accordingly to obtain n fragments. The storage node is then intelligently selected, and each storage node obtains a fragment for storage. The transmission data block can only be restored when at least k shards are obtained at the same time.

[0051] Beneficial effects of the present invention:

[0052] This invention builds a peer-to-peer connection pool by querying, detecting, and selecting online nodes with RTTs below a threshold from the mDNS or DHT system when the client starts up. This completely eliminates reliance on a single central server, eliminating the risks of single points of failure or centralized traffic leakage. It not only dynamically removes nodes with high latency, low bandwidth, or high packet loss rates, but also ensures that only nodes whose quality meets a preset threshold participate in communication and shard storage by normalizing and weighting node performance and historical observation coefficients. This distributed, performance-aware node selection method not only improves the fault tolerance and availability of the entire system, but also significantly reduces the ability of adversaries to monitor, count, or censor single-point traffic through operators or intermediaries. Traffic is evenly distributed across multiple nodes, making it impossible for any monitored node to reconstruct complete metadata or communication patterns, thereby significantly improving metadata privacy protection and censorship resistance from the underlying architecture.

[0053] This invention negotiates a one-time session key based on a Signal X3DH-style Diffie–Hellman operation before any application-layer data is formally exchanged between the two parties. All intermediate secrets and temporary keys are destroyed immediately after the session ends. This design achieves "perfect forward secrecy": even if an attacker obtains the long-term private key of either party in the future, they cannot calculate the session key for the ended session, fundamentally eliminating the risk of "decryption after acquisition." At the same time, the long-term identity key is used only for signing and identity authentication, the signature pre-key is used for mid-term anti-replay protection, and the one-time pre-key is further enhanced to enhance forward secrecy, forming a multi-layer, multi-frequency trust building and fast key agreement system. With the help of decentralized storage to cross-verify public keys and signatures, the entire key exchange process neither relies on a centralized server nor leaks any metadata to relays or observers, thus achieving unparalleled security strength while ensuring communication efficiency.

[0054] After encrypting communication metadata, the present invention adaptively calculates the number of fragments and the recovery threshold based on the size of the transmitted data block. Each fragment is encrypted and stored in nodes in different pools. Only by simultaneously obtaining at least k fragments can the original metadata be restored. This mechanism combines the multiple guarantees of Shamir's secret sharing, which provides information-theoretic security, with symmetric encryption to ensure that even if a large number of nodes are compromised, metadata cannot be leaked at a single point. The adaptive n / k strategy ensures high security while avoiding excessive fragmentation of small messages and performance bottlenecks for large messages, achieving an optimal balance between security and efficiency in storage and recovery overhead. For attackers, no communication metadata can be pieced together unless a threshold number of decentralized nodes are simultaneously compromised, greatly enhancing anti-censorship and data leakage capabilities.

[0055] At the traffic level, the present invention automatically judges traffic analysis threats by real-time monitoring of the Shannon entropy of packet size and the variance of packet intervals. Once it detects that the packet length is excessively concentrated or the timing is excessively regular, it immediately enters the enhanced disturbance mode: the empty packet sending rate and the Poisson generation rate are doubled according to the preset amplification factor, the time slot length is shortened, "extreme empty packets" are forcibly injected, and the empty packets are distributed and sampled with a jitter of ±30%. It also triggers Poisson disturbance and "burst" modes during the silent period to greatly enrich the uncertainty of packet length and sending timing; when the safety indicators are restored, it automatically returns to the basic disturbance mode, and dynamically converges the disturbance intensity at the degradation rate and extends the time slot to avoid performance deterioration when the network is congested or the delay increases. This adaptive perturbation closed loop can maintain the lowest overhead in normal times and quickly switch to the strongest mode when risks are high. It not only completely disrupts traffic characteristics in terms of size and timing, but also ensures that additional bandwidth consumption does not exceed an acceptable range, taking into account both privacy protection and communication quality. Even if the opponent monitors around the clock, it cannot infer any useful social graph or behavior pattern through packet length statistics, time analysis or activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0057] Figure 1 It is a schematic flow chart of the method of the present invention;

[0058] Figure 2 It is a schematic diagram of system module connection of the present invention;

[0059] Figure 3 It is a schematic diagram of the communication disturbance process of the present invention. DETAILED DESCRIPTION

[0060] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0061] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0062] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0063] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0064] According to an embodiment of the present invention, Figure 1 As shown, a high-security instant messaging method is provided, comprising the following steps:

[0065] Step 1: Build a peer-to-peer connection pool to decentralize and avoid single points of failure and concentrated traffic leakage risks:

[0066] When the client starts, it sends a probe packet to any node that is online and has returned a valid address / endpoint in an mDNS or DHT query (i.e., the node can respond to the client's connection request) to measure the node's round-trip latency. If the round-trip latency is below a preset threshold (e.g., 500ms by technicians), the node is marked as available, thereby obtaining the set of available nodes.

[0067] Obtain the performance parameters of available nodes, including round-trip delay, available bandwidth, packet loss rate, and observation coefficient, and record them as RTT, BW, L, and G respectively;

[0068] The round-trip delay, available bandwidth and packet loss rate are normalized respectively. The normalization formula is: RTT max , BW max and L max They are the maximum allowable round-trip delay, the peak bandwidth of the desirable network, and the maximum allowable packet loss rate set by the technicians; the normalized round-trip delay S RTT , available broadband S BW and packet loss rate S LThe value obtained by weighted fusion calculation is multiplied by the observation coefficient to obtain the node performance value; if the node performance value is greater than the preset performance threshold, it is recorded as a candidate node, and each candidate node is screened to form a peer-to-peer connection pool;

[0069] By querying, detecting, and selecting online nodes with RTTs below a threshold through the mDNS or DHT system at client startup to build a peer-to-peer connection pool, this completely eliminates reliance on a single central server, eliminating the risks of single points of failure or concentrated traffic leakage. It not only dynamically removes nodes with high latency, low bandwidth, or high packet loss rates, but also, through normalized weighting of node performance and historical observation coefficients, ensures that only nodes whose quality meets a preset threshold participate in communication and shard storage. This distributed, performance-aware node selection method not only improves the fault tolerance and availability of the entire system, but also significantly reduces the ability of adversaries to monitor, count, or censor single-point traffic through operators or intermediaries. Traffic is evenly distributed across multiple nodes, and even if any node is monitored, it is impossible to reconstruct complete metadata or communication patterns, thereby significantly improving metadata privacy protection and censorship resistance from the underlying architecture.

[0070] Step 2: End-to-end temporary key negotiation:

[0071] Before the two communicating parties (the initiator and the receiver) formally exchange any information, the initiator generates and holds the ECC key pair for a long time. in Used for signature and DH calculation private key, Used for public identity authentication; the receiving end generates and holds an ECC key pair in the same way The receiving end generates a one-time-use ECC key pair with a certain lifespan. And signed with the long-term private key: The receiving end will The signature σ is uploaded to a decentralized storage (such as a blockchain or a public server for verification by the initiator); the receiving end can batch generate several pairs of extremely short-period ECC keys i=1,2,3……, i is the index; each pair is used only once and is removed from the list directly after use to prevent replay;

[0072] During communication, the initiator sends a negotiation request to the receiver, and the initiator obtains the receiver's long-term public key from the public storage. Signature Pre-Key and signature σ, and use Verify the signature; the initiator generates a one-time ECC key locally And construct a negotiation request packet and send it to the receiving end through secure transmission;

[0073] After receiving the request, the receiving end verifies the initiator's and Whether it is in the identity document of the initiator and checks the validity of the OPK index. After successful verification, an empty packet is sent to the initiator or the local key calculation phase is directly entered without additional return delay;

[0074] The initiator and receiver each perform the same Diffie-Hellman calculation locally, generate a shared secret based on the same curve, and concatenate all shared secrets and input them into the HKDF-SHA256 derivation function to generate the final session key K. sess After the session ends, both parties immediately destroy the session key K sess , ensuring forward secrecy; even if an attacker obtains the long-term private keys of both communicating parties in the future, they cannot calculate the past session keys, satisfying the "decryption after acquisition" protection and complete forward secrecy;

[0075] By negotiating a one-time session key based on the SignalX3DH-style Diffie-Hellman operation before the two parties formally exchange any application-layer data, and destroying all intermediate secrets and temporary keys immediately after the session ends, this design achieves "perfect forward secrecy": even if an attacker obtains the long-term private key of either party in the future, he or she will not be able to calculate the session key of the ended session, fundamentally eliminating the risk of "decryption after collection"; at the same time, long-term identity keys are used only for signing and identity authentication, signature pre-keys are used for mid-term anti-replay protection, and one-time pre-keys are used to further enhance forward secrecy, forming a multi-layer and multi-frequency trust building and fast key negotiation system. With the help of decentralized storage to cross-verify public keys and signatures, the entire key exchange process neither relies on centralized servers nor leaks any metadata to relays or observers, thereby achieving unparalleled security strength while ensuring communication efficiency.

[0076] Step 3: Metadata encryption and shard storage:

[0077] The IDs of both communicating parties, message timestamp, message length (message size), message type (text, image, file, etc.), and other optional fields (such as read receipt flag) are collectively referred to as metadata and encapsulated into a binary string denoted as M (serialized according to established protocols, such as Protocol Buffers or custom TLVs); the session key K is extracted. sess , randomly generate an initialization vector N, select some plaintext fields in the metadata as additional authentication data and record them as AD to prevent these fields from being tampered with; call the standard AES-GCM encryption function and output the ciphertext C and authentication tag T GCM ; Specifically:

[0078] Where C is the encrypted output of the same length as M, T GCM It is a message authentication tag used to verify that the ciphertext and additional authentication data have not been tampered with; (N, C, T GCM ) are serially encapsulated into a transmission data block E, E = N‖‖C‖‖T GCM ;

[0079] In order to balance the security strength and storage / recovery overhead of shard storage, the present invention adaptively generates storage parameters according to the transmission data block length l. The storage parameters include the number of shards n and the recovery threshold k (k represents the minimum number of participants. When at least k shards are collected, the original transmission data block can be reconstructed through Lagrangian interpolation). The specific adaptive generation process is as follows: Those skilled in the art set the minimum shard density α min (e.g. 0.1 slice / KB) and the maximum slice density α max (e.g. 0.5 pieces / KB) and the minimum recovery threshold β min (such as 0.5) and the maximum recovery threshold β max (such as 0.8), according to the formula Calculate the number of fragments n, where σ(l) is a normalized function of the transmission data block length l, specifically: Lmax represents the maximum reference data length, and its unit is the same as l, in bytes. It should be noted that as the number of transmitted data blocks increases, n increases from α to min ×l increases smoothly to α max ×l; then according to the formula The recovery threshold k is calculated; as the amount of data increases, the recovery threshold k increases from β min ×l gradually increases smoothly β max ×l, enhance the robustness against shard hijacking; randomly select coefficients a1, a2, a3...a k-1 , construct a polynomial in the large prime field: f(x)=E+a1x+a2x 2 +a3x 3 ...+a j x j ...a k-1 x k-1 , calculate (j,f(j)) according to the number of shards n, and get n shards, where j is the index of any shard;

[0080] Extract the logs of each node in real time and extract the number of received shard requests, the number of successful shard writes, the single storage latency of each storage, the number of shards provided, the number of successful shard reconstructions, and the single response latency of each reconstruction. Divide the number of successful shard writes by the number of received shard requests and multiply by 100 to get the storage success rate, recorded as h1. Then divide the number of successful shard reconstructions by the number of shards provided to get the reconstruction success rate, recorded as h2.

[0081] Box analysis method: extract the single storage delay of each shard write operation, and sort the single storage delays in ascending order to ensure that the format is a one-dimensional numerical sequence. Find the value at the 25% position as the lower quartile Q1, find the value at the 50% (middle) position as the median Q2, find the value at the 75% position as the upper quartile Q3, subtract the lower quartile from the upper quartile (Q3-Q1) to get the IOR, take the minimum value greater than or equal to (Q1-1.5×IOR) among all the sorted values ​​as the lower whisker, and take the maximum value less than or equal to (Q3+1.5×IOR) among all the sorted values ​​as the upper whisker, that is, the whisker top. Points within the range of the upper and lower whiskers are considered outliers; the single storage delay of each shard write operation is input into the "box plot" function, and the parameters are set to display the outliers and the horizontal or vertical direction. The box automatically draws a box plot with Q1, Q2, Q3, upper and lower whisker positions, and the outlier is marked separately; a thick line is drawn at the median position and marked with Q2, and Q1 and Q3 are marked with scales or annotations on the edge of the box. The IQR and whisker top values ​​can be displayed on the outside of the box; Q2, Q3 and upper whiskers are weighted and fused to obtain the storage delay value recorded as Y1; similarly, the above box analysis method is performed on the reconstruction single delay of each reconstruction to output the reconstruction delay value recorded as Y2;

[0082] The storage success rate h1, reconstruction success rate h2, storage delay value Y1 and reconstruction delay value Y2 are calculated according to the formula Normalize and perform weighted fusion calculation to obtain the observation coefficient G of each node, and update the observation coefficient G to step 1 in real time; where T s,max is the maximum acceptable storage latency threshold and T r,max The maximum acceptable reconstruction delay threshold,

[0083] Sort all online nodes in descending order according to their observation coefficients, and remove online nodes with a value less than the minimum observation threshold. Keep a fixed number of online nodes at the top level as preferred nodes for shard storage, and set the observation interval [W1, W2], where W1 is the lower limit of the observation interval and is greater than the observation threshold. Classify preferred nodes greater than the upper limit of the observation interval [W1, W2] into the primary storage pool, classify preferred nodes within the observation interval [W1, W2] into the secondary storage pool, and classify preferred nodes less than the lower limit of the observation interval [W1, W2] into the backup storage pool. Set the primary storage pool to store shards of b1, the secondary storage pool to store shards of b2, and the backup storage pool to store shards of b3, where b1>b2>b3>0, and b1+b2+b3=1 , for example, technicians set them to 50%, 30% and 20% respectively; shards are allocated in random order within the storage pool at the same level to prevent shards from being concentrated in a few nodes. Each node only saves the shard (j, f(j)) it is assigned to and re-encrypts it locally with the session key. When restoring, it only needs to pull fragments from any node layer, totaling k copies. When each node receives a request to receive a shard, the number of received shard requests increases by one. If the write is successful, the number of successful shard writes increases by one, and the single storage delay is recorded. At the same time, if a request to provide a shard is received, the number of provided shards increases by one. If the reconstruction is successful, the number of successful shard reconstructions increases by one, and the single reconstruction delay is recorded. The logs of each node are updated based on the above operations.

[0084] After encrypting the communication metadata, the number of shards and the recovery threshold are adaptively calculated based on the size of the transmitted data block. Each shard is encrypted and stored in nodes of different level pools. Only by obtaining at least k shards at the same time can the original metadata be restored. This mechanism combines the multiple guarantees of Shamir's secret sharing for information-theoretic security and symmetric encryption to ensure that even if a large number of nodes are compromised, metadata cannot be leaked at a single point. At the same time, the adaptive n / k strategy avoids excessive sharding of small messages and performance bottlenecks of large messages while ensuring high security, so that the storage and recovery overhead achieves the best balance between security and efficiency. For attackers, unless a number of decentralized nodes above the threshold are compromised at the same time, they cannot piece together any communication metadata, greatly enhancing their anti-censorship and anti-data leakage capabilities.

[0085] Step 4: Traffic disturbance during communication:

[0086] At the communication end (initiator and receiver), record the byte length sequence U of m outgoing / incoming packets, where U = {u1, u2, u3...u m},u i= the byte length of the i-th outgoing / incoming packet; calculate the Shannon entropy of the packet size and the packet interval variance; if the Shannon entropy is less than the preset entropy (indicating that the packets are too concentrated) or the packet interval variance is less than the preset variance (indicating that the packets are too regular), it is determined that there is a traffic analysis threat on both sides of the communication, and the enhanced perturbation mode is executed; otherwise, the basic perturbation mode is executed. The specific basic perturbation mode is based on the preset initial parameters and randomly selects any u i The traffic perturbation is performed with empty packets of length, and the specific initial parameters include the empty packet rate p0, Poisson rate λ0, and time slot length T0;

[0087] like Figure 3 As shown in Figure 2, the enhanced perturbation mode is specifically:

[0088] 1-1, parameter amplification and time slot adjustment:

[0089] According to the formula p dummy =min(γ p ×p0,1) proportionally amplifies the empty packet rate p0 (empty packet sending probability) in the basic perturbation mode, γ p is the magnification factor of the empty package rate, and γ p >1 (e.g. 2× or 3×), ensuring a significant increase in the number of disturbance packets;

[0090] According to the formula λ dummy =γ λ ×λ0 also amplifies the Poisson rate λ0 (average generation rate) under the basic perturbation mode, γ λ is the amplification factor of the Poisson rate, and γ λ >1, accelerate the generation of empty packets;

[0091] At the time slot length T0 of the basic perturbation pattern, according to the formula T solt =max(T0γ T ,T min ) shortens the time slot, γ T is the amplification factor of the time slot length, T min Minimum time slot threshold to prevent excessive fragmentation;

[0092] The enhanced parameters under the enhanced disturbance mode are obtained, and the specific enhanced parameters are multiplication of the empty packet rate p dummy , doubling the Poisson rate λ dummy and shorten the time slot length T solt ;

[0093] 1-2, the size of the empty package is diversified:

[0094] The number of real messages is counted in real time. After a fixed number of real messages, a very bad empty packet is forcibly sent. The size of the very bad empty packet is the difference between the maximum and minimum byte lengths in the byte length sequence U. The sizes of the remaining empty packets follow a distribution, with a byte length randomly selected from the byte length sequence U. A ±30% jitter is randomly added to each proposed empty packet size.

[0095] 1-3, Sending timing enhancement:

[0096] When shortening the time slot length T solt In the case of multiplying the empty package rate p dummy Make a judgment, randomly select the byte length for each time slot to make an empty packet and send it, and shorten the time slot length T solt A slight random delay is made internally; if the real message interval exceeds the preset interval threshold, there is no need to wait for the next time slot and Poisson perturbation is directly entered; if no real traffic is detected for multiple consecutive times (3 time slots) within any time slot length, the Poisson rate λ is temporarily doubled dummy Then multiply it by the Poisson rate amplification factor to launch a round of blank bursts, continuously firing multiple blank packets to fill the silent window;

[0097] 1-4, monitoring the disturbance effect:

[0098] In enhanced mode, the Shannon entropy of packet length and the packet interval variance are continuously calculated until both return to above the safety threshold (i.e., Shannon entropy ≥ preset entropy and packet interval variance ≥ preset variance), then the system is downgraded back to the "basic perturbation mode";

[0099] 1-5, constraints:

[0100] (1) If the delay of the communication end is greater than the preset delay or the packet loss rate is greater than the preset packet loss rate, the amplification factor is automatically reduced according to the preset degradation rate δ (the amplification factor of the empty packet rate and the amplification factor of the Poisson rate are divided by the degradation rate δ respectively) and T is extended. solt (T solt Multiplied by the degradation rate δ) to avoid network congestion caused by excessive disturbance;

[0101] (2) The maximum amount of empty messages shall not exceed 20% of the total bandwidth;

[0102] At the traffic level, the system automatically identifies traffic analysis threats by monitoring the Shannon entropy of packet size and the variance of packet intervals in real time. Upon detecting excessively concentrated packet lengths or irregular timing patterns, it immediately enters an enhanced perturbation mode. This mode multiplies the empty packet transmission rate and Poisson generation rate by a preset amplification factor, shortens the time slot length, forcibly injects "extremely bad empty packets," and distributes sampled empty packets with ±30% jitter. It also triggers Poisson perturbation and "burst" modes during quiet periods to significantly increase the uncertainty of packet length and transmission timing. Once security indicators recover, the system automatically reverts to the basic perturbation mode. In the event of network congestion or increased latency, the perturbation intensity is dynamically reduced at a degraded rate, and the time slot is extended to prevent performance degradation. This adaptive perturbation closed loop maintains minimal overhead during normal times while rapidly switching to the strongest mode when risks are high. This not only thoroughly disrupts traffic characteristics in terms of size and timing, but also ensures that excess bandwidth consumption does not exceed acceptable limits, balancing privacy protection and communication quality. This prevents adversaries from inferring any useful social graph or behavioral patterns through packet length statistics, time analysis, or activity levels, even with 24 / 7 monitoring.

[0103] According to an embodiment of the present invention, Figure 2 As shown, a high-security instant messaging system is also provided, including:

[0104] The client includes an initiator and a receiver. The client has a built-in key management module and a communication perturbation module. The key management module performs end-to-end temporary key negotiation management for the client before the client officially communicates. The communication perturbation module monitors the client's traffic status during the communication process and determines whether there is a traffic analysis threat. If so, it executes the enhanced perturbation mode; otherwise, it executes the basic perturbation mode.

[0105] The decentralized network has a built-in connection pool management module and a shard storage module. When the client initiates communication, the connection pool management module sends a probe packet to the online node to measure the round-trip delay of the node. If the round-trip delay is lower than the preset threshold, the node is marked as an available node. The performance parameters of the available nodes are obtained, including round-trip delay, available bandwidth, packet loss rate and observation coefficient. The performance parameters are comprehensively calculated and analyzed to obtain the node performance value. If the node performance value is greater than the preset performance threshold, it is recorded as a candidate node, and each candidate node is screened out to form a peer-to-peer connection pool. The shard storage module encapsulates metadata into a transmission data block, adaptively generates the number of shards n and the recovery threshold k for the transmission data block, and shards the transmission data block accordingly to obtain n fragments. The storage node is then intelligently selected, and each storage node obtains a fragment for storage. The transmission data block can only be restored when at least k shards are obtained at the same time.

[0106] The above are merely embodiments of the present invention and are not intended to limit the present invention. It will be apparent to those skilled in the art that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are intended to be included within the scope of the claims of the present invention.

Claims

1. A highly secure instant messaging method, characterized in that: Includes the following methods: Step 1: When communication is initiated, a probe packet is sent to the online node to measure the round-trip delay of the node. If the round-trip delay is lower than the preset threshold, the node is marked as an available node; Obtain performance parameters of available nodes, including round-trip delay, available bandwidth, packet loss rate, and observation coefficient; A comprehensive calculation and analysis of performance parameters is performed to obtain a node performance value. If the node performance value is greater than a preset performance threshold, it is recorded as a candidate node, and each candidate node is screened to form a peer-to-peer connection pool; Step 2: Before the two communicating parties formally exchange information, they negotiate an end-to-end temporary key. Step 3: Encapsulate the metadata into a transmission data block, adaptively generate the number of fragments n and the recovery threshold k for the transmission data block, and fragment the transmission data block accordingly to obtain n fragments; Then, the storage nodes are intelligently selected, and each storage node gets a fragment to store. The transmitted data block can only be restored if at least k fragments are obtained at the same time. Step 4: Monitor the traffic status of the two communicating parties during the communication process and determine whether there is a traffic analysis threat. If so, execute the enhanced perturbation mode; otherwise, execute the basic perturbation mode.

2. A highly secure instant messaging method according to claim 1, characterized in that: The process of determining whether a traffic analysis threat exists during a communication process is as follows: At the communication end, the instant initiator / receiver records the byte length sequence U of m outgoing / incoming packets, where U = {u1, u2, u3...u m }, i=1,2,3..., i is the index, u i = the byte length of the i-th outgoing / incoming packet; calculate the Shannon entropy of the packet size and the packet interval variance; if the Shannon entropy is less than the preset entropy or the packet interval variance is less than the preset variance, then determine that a traffic analysis threat exists; if the Shannon entropy is greater than or equal to the preset entropy and the packet interval variance is greater than or equal to the preset variance, then determine that no traffic analysis threat exists; The basic perturbation mode is based on the preset initial parameters and randomly selects any u i The specific initial parameters include the empty packet rate p0, Poisson rate λ0, and time slot length T0.

3. A highly secure instant messaging method according to claim 2, characterized in that: The enhanced perturbation mode is: 1-1, parameter amplification and time slot adjustment: Set the amplification factor of the empty packet rate, the amplification factor of the Poisson rate, the amplification factor of the time slot length and the minimum time slot threshold, and accordingly amplify the empty packet rate p0 and the Poisson rate λ0 in the basic perturbation mode in proportion to obtain the multiplied empty packet rate p dummy , doubling the Poisson rate λ dummy At the same time, the time slot length T0 under the basic perturbation mode is shortened to obtain the shortened time slot length T solt , and multiply the empty packet rate p dummy , doubling the Poisson rate λ dummy and shorten the time slot length T solt Denoted as the strengthening parameter; 1-2, the size of the empty package is diversified: The number of real messages is counted in real time. After a fixed number of real messages, a very bad empty packet is forcibly sent. The size of the very bad empty packet is the difference between the maximum and minimum byte lengths in the byte length sequence U. The sizes of the remaining empty packets follow a distribution, with a byte length randomly selected from the byte length sequence U. A ±30% jitter is randomly added to each proposed empty packet size. 1-3, Sending timing enhancement: When shortening the time slot length T solt In the case of multiplying the empty package rate p dummy Make a judgment, randomly select the byte length for each time slot to make an empty packet and send it, and shorten the time slot length T solt A random delay is performed internally; if the real message interval exceeds the preset interval threshold, there is no need to wait for the next time slot and Poisson perturbation is directly entered; if no real traffic is detected for a fixed number of consecutive times within any time slot length, the Poisson rate λ is temporarily multiplied dummy Then multiply it by the Poisson rate amplification factor to launch a round of empty package burst; 1-4, monitoring the disturbance effect: In the enhanced mode, the Shannon entropy of packet length and the variance of packet interval are continuously calculated until both are restored to the point where the enhanced perturbation mode is not triggered, and the system is degraded back to the basic perturbation mode. 1-5, constraints: If the delay between the two parties is greater than the preset delay or the packet loss rate is greater than the preset packet loss rate, the amplification factor is automatically reduced and T is extended according to the preset degradation rate δ. solt ; The maximum empty message size shall not exceed 20% of the total bandwidth.

4. A highly secure instant messaging method according to claim 3, characterized in that: The process of comprehensive calculation and analysis of performance parameters is as follows: Extract the performance parameters of available nodes, including round-trip delay, available bandwidth, packet loss rate, and observation coefficient, and record them as RTT, BW, L, and G respectively; The round-trip delay, available bandwidth and packet loss rate are normalized respectively. The normalization formula is: RTT max , BW max and L max They are the maximum allowable round-trip delay, peak bandwidth under the desired network, and maximum allowable packet loss rate set by the technicians; Then the normalized round trip delay S RTT , available broadband S BW and packet loss rate S L The value obtained by weighted fusion calculation is multiplied by the observation coefficient to obtain the node performance value.

5. A highly secure instant messaging method according to claim 4, characterized in that: The key negotiation process is as follows: 5-1: Before communication, both parties generate and hold a pair of ECC identity keys. The receiving end also generates a pair of signature pre-keys and a set of one-time pre-keys. After the initiator obtains the other party's public key, it generates a one-time temporary key. 5-2: During communication, the initiator sends a negotiation request to the receiver, constructs a negotiation request packet, and sends it to the receiver via secure transmission. The receiver verifies the request and, upon successful verification, sends an empty packet to the initiator or directly enters the local key calculation phase, without any additional return delay. 5-3: The communicating parties generate a session key based on the same operation. After the communication ends, both parties immediately destroy the session key to ensure forward secrecy.

6. A highly secure instant messaging method according to claim 5, characterized in that: The ECC identity key generation process is: Before the two communicating parties formally exchange any information, the initiator generates and holds the ECC key pair for a long time. in Used for signature and DH calculation private key, Used for public identity authentication; the receiving end generates and holds an ECC key pair in the same way The receiving end generates a one-time-use ECC key pair with a certain lifespan. And signed with the long-term private key: The receiving end will The signature σ is uploaded to the decentralized storage; the receiving end generates several pairs of extremely short-period ECC keys in batches i is the index; each pair is used only once and then removed from the list to avoid replay.

7. A highly secure instant messaging method according to claim 6, characterized in that: The metadata encapsulation and adaptive sharding process is as follows: The IDs of both parties, message timestamp, message length, message type and other fields are collectively referred to as metadata, and are encapsulated into a binary string denoted as M; the session key K is extracted. sess , randomly generate an initialization vector N, randomly select a plaintext field in the metadata as additional authentication data and record it as AD; call the standard AES-GCM encryption function and output the ciphertext C and authentication tag T GCM Specifically: Where C is the encrypted output of the same length as M, T GCM It is a message authentication tag used to verify that the ciphertext and additional authentication data have not been tampered with; (N, C, T GCM ) are serially encapsulated into a transmission data block E, E = N||C||T GCM ; Extract the transmission data block length l and set the minimum fragmentation density α min With the maximum fragment density α max and the minimum recovery threshold β min and the maximum recovery threshold β max , according to the formula Calculate the number of fragments n, where σ(l) is a normalized function of the transmission data block length l, specifically: Lmax represents the maximum reference data length, and its unit is the same as l, in bytes; according to the formula Calculate the recovery threshold k; Randomly select coefficients a1, a2, a3...a k-1 , construct a polynomial in the large prime field: f(x)=E+a1x+a2x 2 +a3x 3 ...+a j x j ...a k-1 x k-1 , calculate (j,f(j)) according to the number of shards n, and get n shards, where j is the index of any shard.

8. A highly secure instant messaging method according to claim 7, characterized in that: The process of intelligently selecting nodes for storage is as follows: Extract the logs of each node in real time and extract the number of received shard requests, the number of successful shard writes, the single storage latency of each storage, the number of shards provided, the number of successful shard reconstructions, and the single response latency of each reconstruction. Divide the number of successful shard writes by the number of received shard requests and multiply by 100 to get the storage success rate. Then divide the number of successful shard reconstructions by the number of shards provided to get the reconstruction success rate. The box analysis method is used to analyze the single storage delay and single reconstruction delay respectively to obtain the storage delay value and reconstruction delay value; Normalize the storage success rate, reconstruction success rate, storage delay value, and reconstruction delay value, and perform weighted fusion calculation to obtain the observation coefficient of each node, and update the observation coefficient to step 1 in real time; Sort all online nodes by their observation coefficients from large to small, remove online nodes with a value less than the minimum observation threshold, retain a fixed number of online nodes at the top as the preferred nodes for shard storage, and set the observation interval; The preferred nodes with a value greater than the upper limit of the observation interval are classified into the primary storage pool, the preferred nodes within the observation interval are classified into the secondary storage pool, and the preferred nodes with a value less than the lower limit of the observation interval are classified into the backup storage pool. Set up a primary storage pool to store shards of b1, a secondary storage pool to store shards of b2, and a backup storage pool to store shards of b3, where b1>b2>b3>0 and b1+b2+b3=1. Shards are randomly assigned within the same storage pool layer. Each node only saves its assigned shard (j, f(j)) and re-encrypts it locally with the session key. During recovery, simply pull the shards from any node layer, up to a total of k shares. When each node receives a request to receive a shard, the number of received shard requests increases by one. If the write is successful, the number of successful shard writes increases by one, and the single storage delay is recorded. At the same time, if a request to provide a shard is received, the number of provided shards increases by one. If the reconstruction is successful, the number of successful shard reconstructions increases by one, and the single reconstruction delay is recorded. The log of each node is updated according to the shard storage and reconstruction operations of each node.

9. A highly secure instant messaging method according to claim 8, characterized in that: The box analysis method is: Extract the single storage latency of each shard write operation and sort the single storage latency in ascending order to ensure that the format is a one-dimensional numerical sequence. Find the value at the 25th percentile position as the lower quartile Q1, the value at the 50th percentile position as the median Q2, and the value at the 75th percentile position as the upper quartile Q3. Subtract the lower quartile from the upper quartile to get the IOR. Take the minimum value greater than or equal to (Q1-1.5×IOR) among all the sorted values ​​as the lower whisker, and take the maximum value less than or equal to (Q3+1.5×IOR) among all the sorted values ​​as the upper whisker, i.e., the whisker top. Points outside the range of the upper and lower whiskers are considered outliers. Input the single storage latency of each shard write operation into the "Box Plot" function and set parameters to display outliers and horizontal or vertical directions. The box automatically draws a box plot with Q1, Q2, Q3, upper and lower whisker positions, and plots outliers individually. Draw a thick line at the median position and label Q2. Mark Q1 and Q3 at the edges of the box. Optionally display the IQR and whisker top values ​​outside the box. Q2, Q3 and the above must be weighted and fused to obtain the storage delay value; similarly, the above box analysis method is performed on the reconstruction single delay of each reconstruction to output the reconstruction delay value.

10. A highly secure instant messaging system, characterized in that A high-security instant messaging method according to any one of claims 1 to 8, the system comprising: The client includes an initiator and a receiver. The client has a built-in key management module and a communication perturbation module. The key management module performs end-to-end temporary key negotiation management for the client before the client officially communicates. The communication perturbation module monitors the client's traffic status during the communication process and determines whether there is a traffic analysis threat. If so, it executes the enhanced perturbation mode; otherwise, it executes the basic perturbation mode. The decentralized network has a built-in connection pool management module and a shard storage module. When the client initiates communication, the connection pool management module sends a probe packet to the online node to measure the round-trip delay of the node. If the round-trip delay is lower than the preset threshold, the node is marked as an available node. The performance parameters of the available nodes are obtained, including round-trip delay, available bandwidth, packet loss rate and observation coefficient. The performance parameters are comprehensively calculated and analyzed to obtain the node performance value. If the node performance value is greater than the preset performance threshold, it is recorded as a candidate node, and each candidate node is screened out to form a peer-to-peer connection pool. The shard storage module encapsulates metadata into a transmission data block, adaptively generates the number of shards n and the recovery threshold k for the transmission data block, and shards the transmission data block accordingly to obtain n fragments. The storage node is then intelligently selected, and each storage node obtains a fragment for storage. The transmission data block can only be restored when at least k shards are obtained at the same time.

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