A method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain

Abstract

This invention provides a method for selecting the optimal distributor in a blockchain-based peer-to-peer content distribution network. Under the conditions of a synchronous network, a static polynomial-time adversary, a global predicate defining the correctness of a given content, and a global synchronization time function, a verifiable distribution quality protocol is used to certify the quality of content distribution in the interaction between a sender S, a receiver R, and a verifier V. A comprehensive distributor reputation evaluation mechanism is established based on quantifiable and verifiable distributor service quality and domain entropy weight calculation to obtain the comprehensive credibility of each distributor. An optimal distributor selection algorithm is designed to select the most suitable distributor based on the comprehensive credibility of the distributor and the total budget of the content provider. This invention addresses the issue of trustworthiness of distributor evaluation dimension information, selects the most suitable distributor within the budget provided by the content provider, improves distribution efficiency, and fully guarantees security and efficiency.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and in particular to a method for selecting an optimal distributor in a peer-to-peer content distribution network based on blockchain. Background Art

[0002] With the development of the internet and the enrichment of social life, the amount of online content transmission has increased dramatically. According to Cisco statistics, by the end of 2022, video will account for over 82% of all content transmitted on the internet. To cope with such enormous data transmission demands, content providers typically rely on content delivery networks (CDNs) for rapid content distribution. In centralized CDNs, content distribution servers are centrally provided by a single distribution service provider. However, these networks have many drawbacks, including: users cannot predict peak bandwidth requirements, necessitating the purchase of excess bandwidth to accommodate peak requests; insufficient system robustness, making centralized servers vulnerable to cyberattacks and creating a single point of failure; and high costs, as users ultimately have to pay for idle server resources. Peer-to-peer networks offer great potential to address these issues. The system model of a peer-to-peer CDN is that content providers own and intend to sell content. Content distributors contribute storage and bandwidth resources to enable rapid content distribution and receive compensation from the content providers. Content consumers obtain the content they need from the content distributors and pay the content providers a fee.

[0003] Blockchain, as a revolutionary distributed ledger technology, can reshape the trust model between distrusting peers in distributed networks. Blockchain technology possesses two key characteristics: asymmetric incentive exchange. Token mechanisms within blockchains (such as cryptocurrencies) can incentivize participants in peer-to-peer content distribution networks to actively share their asymmetric resource needs. Second, it provides a trusted third party. Blockchains can replace traditional intermediaries, acting as trusted third parties (TTPs) solely through cryptographic algorithms or tools. Consequently, numerous studies have combined blockchain technology with peer-to-peer content distribution networks (PCDNs), demonstrating its effective application. For example, to ensure the security of P2P content distribution networks, specifically ensuring that all participants receive their fair share (i.e., content providers should receive corresponding compensation for providing content, content distributors should receive corresponding compensation for contributing bandwidth resources, and content consumers should only pay for receiving the correct content), He designed a secure and efficient blockchain-based P2P download transmission protocol for a wide range of typical download scenarios, such as software packages and audio and video content distribution and download services. Goyal proposed Gringotts, a secure monetary reward system for peer-to-peer content distribution networks. This system allows content providers to verify the correct distribution of their content by providing a new proof-of-delivery mechanism. Almashaqbeh proposed Cachecash, a decentralized content distribution network based on cryptocurrency. This system bypasses the centralized management methods of existing content distribution network companies, allowing end users to organically set up new caches in exchange for cryptocurrency. Qureshi proposed a blockchain-based peer-to-peer content distribution system that uses technologies such as anti-collusion fingerprinting, perceptual hashing functions, and peer-to-peer content distribution networks to provide copyright protection, anti-collusion capabilities, micropayments, and piracy tracking.

[0004] However, while blockchain-based peer-to-peer content distribution networks ensure important security attributes for participants, the efficiency of content block distribution still remains a problem. One of the main reasons is the lack of, or failure to identify, the most suitable distributor. Specifically, the aforementioned literature ignores the distributor selection process and randomly delegates distributors. It also considers only a single evaluation dimension for distributors, resulting in a lack of universality in distributor selection. Even when multiple dimensions are considered, the collected information for each dimension cannot be verified, leading to unreliable selection processes. Therefore, selecting reliable and efficient content distributors can improve the distribution efficiency of content blocks in peer-to-peer content distribution networks and achieve reliable and efficient transmission of content blocks.

[0005] Currently, blockchain-based peer-to-peer content distribution networks face distribution efficiency challenges. More specifically, distribution efficiency depends heavily on the appropriate selection of distributors. Existing distributor selection solutions primarily include random selection and evaluation-based selection. The former randomly selects from candidate distributors without employing a specific selection strategy, resulting in suboptimal distribution performance. The latter evaluates distributor behavior and generates an overall assessment, such as overall credit or reputation, to prioritize distributors. Evaluation-based methods can be further categorized as subjective (i.e., consumer-based) and objective, but these approaches suffer from issues such as a single dimension and unreliable information collection. Summary of the Invention

[0006] The purpose of this invention is to provide a method for selecting the optimal distributor in a blockchain-based peer-to-peer content distribution network. By considering multiple objective dimensions of the distributor, a comprehensive evaluation mechanism is designed. The credibility issue of dimensional information is solved in a verifiable and automatic settlement manner through smart contracts. The most suitable distributor is selected within the budget provided by the content provider, thereby improving distribution efficiency.

[0007] To achieve the above objectives, the present invention provides a method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain. The specific steps are as follows:

[0008] In synchronous networks, specific protocol instances, global predicates for the correctness of given content , global synchronization time function Verify the quality of the distribution protocol through verifiable validation under conditions of static polynomial-time adversaries The proof of the quality of the distributor's distribution is achieved in the interaction between the sender S, the receiver R, and the verifier V (i.e., the blockchain), including:

[0009] Sender S sends the first content block to the blockchain. The chain records the time of sending as the start time of sending. Receiver R receives the first content block through the chain and returns a "receipt" to the sender.

[0010] For each subsequent content block, the receiver R will send a "receipt" back to the sender to confirm that the content block has indeed been distributed. The sender will continue to send the next content block after verifying that the receipt is correct.

[0011] Content m is divided into n blocks of equal size Ordered content blocks, starting with Initial content blocks for content distribution, , the sender S uses the latest "receipt" containing the index of the ordered content block to quantify the distributor's service quality, including three aspects:

[0012] First, once the protocol is completed, the number of distribution tasks of sender S will increase by 1;

[0013] Second, when the sender S uses the latest receipt to get the payment from the blockchain, the blockchain can calculate how many ordered content blocks have been distributed in total, combined with the size of each block , calculate the total content distribution volume;

[0014] Third, the blockchain records the time when the sender sends the latest receipt as the end time. Based on this, combined with the start time, the blockchain automatically calculates the total time spent. Combined with the amount of content distributed this time, the speed of this content distribution is calculated, and combined with the previous average speed to update the sender's total average speed.

[0015] Establish a comprehensive reputation evaluation mechanism for distributors based on the domain entropy and the weight calculation of the distribution quality dimension; in the application scenario, the sender S is transformed into the distributor d;

[0016] Combining the above-mentioned quantifiable and verifiable distributor service quality proof and the distributor comprehensive reputation evaluation mechanism based on the distribution quality dimension weight calculation based on domain entropy, the comprehensive credibility of each distributor is obtained;

[0017] Based on the combined credibility of the distributor and the total budget of the content provider , use the optimal distributor selection algorithm to select the most suitable distributor.

[0018] Preferably, the latest receipt containing the index of the ordered content block is used to quantify the number of ordered content blocks distributed, the total amount of content distributed, the total distribution time and the calculated distribution speed.

[0019] Preferably, the sender S uses the interface , by inputting n ordered content blocks and corresponding verification string sequences Activation; after activation, the sender S interacts with the receiver R and opens an interface .

[0020] Preferably, the receiver R uses the interface , by entering the global predicate and the initial content block index Activate and interact with the sender S; at the same time, output ,in , , and each Through global predicates Verified as valid.

[0021] Preferably, the verifier V is indexed by the initial content block , by the interface Proof of Generation And other information received from S and R as input, output the total amount of distributed content , The number of ordered content blocks for distribution;

[0022] Validator V uses smart contracts deployed in the blockchain network Once instantiated, the verifier stores data and executes the agreed-upon program when predetermined conditions are met.

[0023] Preferably, the sender S and the receiver R generate a public key pair and , and their public keys are declared bound to themselves.

[0024] Preferably, the distributor starts a timer And continue for two rounds, initialize a variable Used to save the latest receipt proof of sender S and perform the following:

[0025] For the initial content block, that is , S distributes to V ,in: It is the protocol session ID, start_chunk is a string used to indicate the initial content block. Indicates the subscript of the initial content block, Indicates the The initial content block and its digital signature, and wait for the response message from R , where receipt is a string indicating that this is receipt information, and i is the index of the ordered content block. The receipt for the i-th ordered content block sent back by the receiver is the digital signature; , i.e. non-initial content block: S distributes to R , and wait for the response message, where send represents a string to indicate that this is a message to be sent; if If it expires before receiving the receipt, the iteration is interrupted; otherwise S verifies , if true, then output , reset And continue to the next iteration; if not, interrupt the iteration; when When called, it returns proof and stop.

[0026] Preferably, the recipient starts a timer that lasts two rounds , and execute as follows: For , waiting for distribution from V ;for , waiting for distribution from S , if the timer If the timeout is exceeded before receiving the message, stop; otherwise R verifies whether the global predicate ɸ is satisfied ; If true, reset , output , and distribute to S ,in ; If false, stop.

[0027] Preferably, the distributor's comprehensive reputation assessment mechanism includes:

[0028] First, the dimension value of each dimension is normalized to obtain ;

[0029] For each distributor d selected from the distributor set D, each dimension Based on neighborhood radius Computing neighborhood granularity ;

[0030] based on Calculating neighborhood entropy ,based on Calculate the weight value of each dimension ;

[0031] Each distributor d selected from the distributor set D is assigned a distribution task based on the number of distribution tasks, the total amount of distribution content, and the average distribution speed. and Calculate the value of the distributor's comprehensive credibility , update the distributor d , and added to the ordered distributor set in descending order of comprehensive credibility .

[0032] Preferably, the optimal distributor selection algorithm includes

[0033] First, choose a distribution budget that The distributor of all n ordered content block distribution tasks within ; Then if there is a remaining budget, add a cost performance The highest distributor, until the budget is exhausted, where Indicates other distributors Bid a fee for each ordered content block, Indicates other distributors comprehensive credibility.

[0034] Therefore, this invention adopts the aforementioned method for selecting the optimal distributor in a blockchain-based peer-to-peer content distribution network. By considering multiple objective dimensions of a distributor, a comprehensive evaluation mechanism is designed. This mechanism also addresses the issue of trustworthiness of dimensional information through automated settlement and verifiability through smart contracts. This method selects the most appropriate distributor within the budget provided by the content provider, improving distribution efficiency. This ensures complete security and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flowchart of a method for selecting the optimal distributor in a blockchain-based peer-to-peer content distribution network;

[0036] Figure 2 The on-chain gas cost of each function in the smart contract;

[0037] Figure 3 Assign weights to different neighborhood radii;

[0038] Figure 4 Results for selected distributors under different budgets;

[0039] Figure 5 The time cost of distributing content blocks of different sizes;

[0040] Figure 6 This is a time cost comparison chart. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0042] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0043] Example 1

[0044] like Figure 1 As shown in FIG, a method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain, the specific steps are as follows:

[0045] In synchronous networks, specific protocol instances, global predicates for the correctness of given content , global synchronization time function Verify the quality of the distribution protocol through verifiable validation under conditions of static polynomial-time adversaries The proof of the quality of the distributor's distribution is achieved in the interaction between the sender S, the receiver R, and the verifier V (i.e., the blockchain), including:

[0046] Step 1: Verify the protocol through verifiable distribution quality under synchronous network assumption and independent setting Against probabilistic polynomial-time and static adversaries in S, R, and V, the implementation has global predicates and global synchronization time oracle Distribution quality verification, including

[0047] Sender S sends the first content block to the blockchain. The chain records the time of sending as the start time of sending. Receiver R receives the first content block through the chain and returns a "receipt" to the sender.

[0048] For each subsequent content block, the receiver R will send a "receipt" back to the sender to confirm that the content block has indeed been distributed. The sender will continue to send the next content block after verifying that the receipt is correct.

[0049] Content m is divided into n blocks of equal size Ordered content blocks, starting with Initial content blocks for content distribution, , the sender S uses the latest "receipt" containing the index of the ordered content block to quantify the distributor's service quality, including three aspects:

[0050] First, once the protocol is completed, the number of distribution tasks of sender S will increase by 1;

[0051] Second, when the sender S uses the latest receipt to get the payment from the blockchain, the blockchain can calculate how many ordered content blocks have been distributed in total, combined with the size of each block , calculate the total content distribution volume;

[0052] Third, the blockchain records the time the sender sends their most recent receipt as the end time. Combining this with the start time, the blockchain automatically calculates the total time spent. This, combined with the amount of content distributed, calculates the speed of this content distribution. This speed is then combined with the previous average speed to update the sender's overall average speed. While intuitively, the distributor might lose bandwidth for delivering a single, ordered block of content, this distribution process is clearly secure and efficient.

[0053] The number of ordered content blocks delivered, the total amount of content delivered, the total delivery time, and the resulting delivery speed are quantified using the latest receipt containing the index of the ordered content block.

[0054] The interaction parties of the distribution quality verification protocol are: interactive multi-time Turing machine (ITM) sender S, ITM receiver R and non-interactive Turing machine verifier V, and follow the following rules:

[0055] The sender S can use the interface , by inputting n ordered content blocks and corresponding verification string sequences Activate. A global predicate ɸ Used to verify Is it the i-th valid block of content m? Once activated, the sender S interacts with the receiver R and opens an interface , this interface can be called to generate a proof , used to represent verification information related to the distribution of ordered content blocks.

[0056] The receiver R can use the interface , by entering the global predicate and the initial content block index Activate and interact with the sender S. At the same time, output ,in , , and each Through global predicates Verified as valid.

[0057] Validator V is indexed by the initial content block ,Depend on Proof of Generation And other information received from S and R as input, output the total amount of distributed content , The number of ordered content blocks for distribution.

[0058] Distribution Quality Verification Protocol Construction: To implement the verification setting, the sender S and the receiver R generate a public key pair and , and their public keys are declared to be bound to themselves. Therefore, under the synchronous network assumption and independent setting, it can be achieved through the protocol Fighting Probabilistic Polynomial-Time (PPT) and Static Adversaries in S, R, and V for Encoding with Global Predicates and global synchronization time oracle Verification of the quality of distribution (e.g., instantiation via the Network Time Protocol NTP).

[0059] Construction of sender S: Once sender S passes ,enter , , and the initial content block index Activate. Start a timer And continue for two rounds, initialize a variable Used to save the latest receipt proof of sender S and perform the following:

[0060] For the initial content block, that is , S distributes to V ,in: It is the protocol session ID, start_chunk is a string used to indicate the initial content block. Indicates the subscript of the initial content block, Indicates the The initial content block and its digital signature, and wait for the response message from R , where receipt is a string indicating that this is receipt information, and i is the index of the ordered content block. The receipt for the i-th ordered content block sent back by the receiver is the digital signature; , i.e. non-initial content block: S distributes to R , and wait for the response message; if If it expires before receiving the receipt, the iteration is interrupted; otherwise S verifies , if true, then output , reset And continue to the next iteration; if not, interrupt the iteration; when When called, it returns proof and stop.

[0061] Construction of receiver R: Receiver R is constructed by ,enter , initial content block index and Activate. Starts a timer that lasts two rounds. , and execute as follows: For , waiting for distribution from V ;for , waiting for distribution from S , if the timer If the timeout is exceeded before receiving the message, stop; otherwise R verifies whether the global predicate ɸ is satisfied ; If true, reset , output , and distribute to S ,in ; If false, stop;

[0062] Verifier V construction: Verifier V is deployed in the blockchain network through a smart contract Instantiated (e.g., Ethereum), validators can store data securely and transparently and execute agreed programs when predetermined conditions are met. The specific functions are shown in Table 1.

[0063] Table 1 Contract Function: Function

[0064]

[0065] Step 2: Establish a comprehensive reputation evaluation mechanism for distributors based on the weight calculation of the distribution quality dimension based on domain entropy. In the application scenario, the sender S is transformed into the distributor d. Combining the above-mentioned quantifiable and verifiable distributor service quality proof and the comprehensive reputation evaluation mechanism for distributors based on the weight calculation of the distribution quality dimension based on domain entropy, the comprehensive credibility of each distributor is obtained.

[0066] According to the trust evaluation dimensions in step 1: the number of delivery tasks delivery_nums, the total amount of distributed content total_amount, and the average distribution speed avg_speed, the comprehensive trustworthiness of a distributor can be calculated. First, the dimension value of each dimension is normalized by formula (1):

[0067] (1)

[0068] in Representation Dimension Distributor The specific dimension value of and Respectively represent all distributors in the dimension The maximum and minimum values ​​under .

[0069] According to the normalized results, the dimension The neighborhood entropy NE under can be calculated by formula (2)

[0070] (2)

[0071] in Indicates the neighborhood granularity. Representative Distributor With other distributors The similarities between them. is the neighborhood radius. Neighborhood entropy is used to represent the dimension The average neighborhood uncertainty can characterize the diversity of distributors in different dimensions.

[0072] Dimension-based Neighborhood entropy, dimension The weight can be calculated by formula (3)

[0073] (3)

[0074] in , These are the three dimensions that can be verified in step 1. At the same time, a sliding time window is introduced to maintain the stability of the weight of each dimension over a period of time.

[0075] By aggregating all dimensions { :delivery_nums; : total_amount; :avg_speed;}, Distributor The overall credibility It can be calculated by formula (4)

[0076] (4)

[0077] According to the obtained comprehensive credibility of each distributor, all distributors are sorted in descending order according to the comprehensive credibility to obtain an ordered distributor set, as shown in Algorithm 1.

[0078] Table 2 Algorithm 1: Distributor comprehensive credibility evaluation algorithm

[0079]

[0080] Step 3: Based on the comprehensive credibility of the distributor and the total budget of the content provider , use the optimal distributor selection algorithm to select the most suitable distributor

[0081] When a content distribution task is issued by a content provider P, the distributors can use their respective bid fees for each ordered content block Based on the combined credibility of the distributor and the total budget of the content provider , use Algorithm 2 to select the most suitable distributor. The core idea is: first select a distributor that can meet the distribution budget. The distributor of all n ordered content block distribution tasks within ; Then if there is a remaining budget, add a cost performance The highest distributor is selected until the budget is exhausted. Therefore, k distributors can be solved in a greedy manner using Algorithm 2. In addition, a system parameter is introduced to ensure that the workload of different distributors is balanced during parallel distribution.

[0082] Table 3 Algorithm 2: Optimal Distributor Selection Algorithm

[0083]

[0084] Verifiable distribution quality verification protocols based on authentication, network synchronization, and independent setup In the case of static PPT adversaries corrupting distributors and receivers, it meets the requirements of termination, integrity, and verifiability. Distribution fairness and verifiable distribution time cost.

[0085] Termination and integrity: After the verifiable distribution quality verification protocol is executed, each participant can obtain the output they deserve, that is, the content consumer downloads the correct content; the content distributor receives the fees paid by the content provider; and the content provider obtains the net profit, which is the fees paid by the content consumer minus the fees paid to the content distributor;

[0086] Verifiable Distribution fairness: On the one hand, malicious distributors corrupted by opponents It is possible to still receive a "receipt" after termination, for example, to obtain an index of The honest receiver R can ensure that it has a valid sequence of , An ordered collection of content blocks, where is the index of the initial content block, unless the malicious distributor It is possible to forge the recipient's signature. However, this would require breaking the signature scheme. of Security, this probability is negligible. On the other hand, for a malicious receiver who is corrupted by the adversary , if the verifier V is the input party and receives the proof from the honest sender S And output , then the sender S can distribute at most ordered content block pairs, that is, at most one ordered content block size is wasted bandwidth. Strictly guarantee verifiable Distribution fairness.

[0087] Verifiable distribution time cost: The sender S needs to send the first The initial content block is sent to the smart contract, which will automatically record the timestamp of the distribution start. When the smart contract verifies the result, if the proof is true, it records the end timestamp of the distribution and updates the distributor's delivery_nums, total_amount, and avg_speed. In this process, due to the incentive of reputation evaluation, the sender S will provide valid proof to the smart contract as soon as possible. (To a certain extent, it can improve distribution efficiency) to obtain rewards and higher reputation evaluation results. Since the start and end times are stored by the smart contract, the distribution time cost is verifiable and credible.

[0088] At the same time, the distribution quality verification protocol can be verified Initial content block index Can start from any specific location so that the distribution quality verification protocol can be verified Ability to resume content delivery after unpredictable termination; Session ID Designed to resist replay attacks.

[0089] Verify the quality of the protocol through verifiable distribution , the present invention first solves the credibility problem of collecting dimension values ​​in reputation evaluation. At the same time, smart contracts The implementation and deployment were carried out on the Ethereum test network, and the on-chain Gas cost was evaluated, such as Figure 2 As shown, the on-chain costs of all parties are acceptable.

[0090] To demonstrate the effectiveness of the proposed optimal distributor selection algorithm, an experimental simulation was conducted by randomly generating trust values ​​of three dimensions for 1,000 distributor nodes. The experimental environment was a PC with Windows 10, a Core(TM) i5-11400H CPU 2.7GHz, and 16GB RAM. The code was implemented using Python 3.7 in the IDE Pycharm 2020. First, the assignment of dimension weights was determined experimentally. The dimension weights are determined by the neighborhood radius. It is decided that the neighborhood radius should be set as small as possible and can effectively distinguish the three dimensions. Through ten-fold cross validation, e.g. Figure 3 In the subsequent experiments shown, we set the neighborhood radius to 0.8.

[0091] Then, according to different budgets, Algorithm 2 is used to select the optimal distributor, such as Figure 4 As shown in Figure 2, the number of selected distributors and the overall credibility under different budgets are shown. The experimental results show that Algorithm 2 can adaptively select k distributors. At the same time, as the budget increases, the selected content distributors have higher overall credibility.

[0092] The present invention is directed to a peer-to-peer content distribution network based on blockchain, which can adaptively select a set of k distributors with the largest overall credibility under a budget given by a content provider.

[0093] The peer-to-peer content distribution process was implemented using the Netty framework. The experiment was run on three virtual machines (VMs) in the same local area network, acting as the provider, distributor, and consumer respectively. The network bandwidth between them was 1GB, and each VM was equipped with 2 CPUs, 4GB of memory, and a 200GB hard drive. Figure 5 The time cost of delivering content of different sizes using different ordered content chunk sizes is shown.

[0094] like Figure 6As shown, the present invention is compared with related works (the greedy algorithm in Algorithm 3 of Table 4, random selection, and selection through a single dimension). Experimental results show that the optimal distributor selected by the present invention through the credibility evaluation mechanism can achieve higher overall credibility.

[0095] Table 4 Algorithm 3: Greedy Algorithm

[0096]

[0097] Therefore, this invention adopts the aforementioned method for selecting the optimal distributor in a blockchain-based peer-to-peer content distribution network. By considering multiple objective dimensions of a distributor, a comprehensive evaluation mechanism is designed. This mechanism also addresses the issue of trustworthiness of dimensional information through automated settlement and verifiability through smart contracts. This method selects the most appropriate distributor within the budget provided by the content provider, improving distribution efficiency. This ensures complete security and efficiency.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for selecting the best distributor in a peer-to-peer content distribution network based on blockchain, characterized in that: The specific steps are as follows: In synchronous networks, specific protocol instances, global predicates for the correctness of given content , global synchronization time function Verify the quality of the distribution protocol through verifiable validation under conditions of static polynomial-time adversaries The proof of the quality of the distributor's distribution is implemented in the interaction between the sender S, the receiver R, and the verifier V, including: Sender S sends the first content block to the blockchain. The chain records the sending time as the start time. Receiver R receives the first content block through the chain and returns a "receipt" to the sender. For each subsequent content block, the receiver R will send a "receipt" back to the sender to confirm that the content block has indeed been distributed. The sender will continue to send the next content block after verifying that the receipt is correct. Content m is divided into n blocks of equal size Ordered content blocks, starting with Initial content blocks for content distribution, , the sender S uses the latest "receipt" containing the index of the ordered content block to quantify the quality of service of the distributor, including three aspects: First, once the protocol is completed, the number of distribution tasks of sender S will increase by 1; Second, when the sender S uses the latest receipt to get the payment from the blockchain, the blockchain can calculate how many ordered content blocks have been distributed in total, combined with the size of each block , calculate the total content distribution volume; Third, the blockchain records the time when the sender sends the latest receipt as the end time. Based on this, combined with the start time, the blockchain automatically calculates the total time spent. Combined with the amount of content distributed this time, the speed of this content distribution is calculated, and combined with the previous average speed to update the sender's total average speed. Establish a comprehensive reputation evaluation mechanism for distributors based on the domain entropy and the weight calculation of the distribution quality dimension; in the application scenario, the sender S is transformed into the distributor d; Combining the quantifiable and verifiable distributor service quality proof and the distributor comprehensive reputation evaluation mechanism based on the domain entropy distribution quality dimension weight calculation, the comprehensive credibility of each distributor is obtained; Based on the combined credibility of the distributor and the total budget of the content provider , use the optimal distributor selection algorithm to select the most suitable distributor.

2. The method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain according to claim 1, characterized in that: The number of ordered content blocks delivered, the total amount of content delivered, the total delivery time, and the resulting delivery speed are quantified using the latest receipt containing the index of the ordered content block.

3. The method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain according to claim 1, characterized in that: Sender S uses the interface , by inputting n ordered content blocks and corresponding verification string sequences Activation; after activation, the sender S interacts with the receiver R and opens an interface .

4. The method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain according to claim 3, characterized in that: Receiver R uses the interface , by entering the global predicate and the initial content block index Activate and interact with the sender S; at the same time, output ,in , , and each Through global predicates Verified as valid.

5. The method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain according to claim 4, characterized in that: Validator V is indexed by the initial content block , by the interface Proof of Generation And other information received from S and R as input, output the total amount of distributed content , the number of ordered content blocks for distribution; Validator V uses smart contracts deployed in the blockchain network Once instantiated, the verifier stores data and executes the agreed-upon program when predetermined conditions are met.

6. The method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain according to claim 3, characterized in that: The sender S and the receiver R generate a public key pair and , and their public keys are declared bound to themselves.

7. The method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain according to claim 6, characterized in that: The distributor starts a timer And continue for two rounds, initialize a variable Used to save the latest receipt proof of sender S and perform the following: For the initial content block, that is , S distributes to V ,in: It is the protocol session ID, start_chunk is a string used to indicate the initial content block. Indicates the subscript of the initial content block, Indicates the The initial content block and its digital signature, and wait for the response message from R , where receipt is a string indicating that this is receipt information, and i is the index of the ordered content block. The receipt for the i-th ordered content block sent back by the receiver is the digital signature; , i.e. non-initial content block: S distributes to R , and wait for the response message, where send represents a string to indicate that this is a message to be sent; if If it expires before receiving the receipt, the iteration is interrupted; otherwise S verifies , if true, then output , reset And continue to the next iteration; if not, interrupt the iteration; when When called, it returns proof and stop.

8. The method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain according to claim 7, characterized in that: The receiver starts a timer that lasts two rounds , and execute as follows: For , waiting for distribution from V ;for , waiting for distribution from S , if the timer If the timeout is exceeded before receiving the message, stop; otherwise R verifies whether the global predicate ɸ is satisfied ; If true, reset , output , and distribute to S ,in ; If false, stop.

9. The method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain according to claim 8, characterized in that: Distributor comprehensive reputation assessment mechanism, including: First, the dimension value of each dimension is normalized to obtain ; For each distributor d selected from the distributor set D, each dimension Based on neighborhood radius Computing neighborhood granularity ; based on Calculating neighborhood entropy ,based on Calculate the weight value of each dimension ; Each distributor d selected from the distributor set D is assigned a distribution task based on the number of distribution tasks, the total amount of distribution content, and the average distribution speed. and Calculate the value of the distributor's comprehensive credibility , update the distributor d , and added to the ordered distributor set in descending order of comprehensive credibility .

10. The method for selecting the optimal distributor in a peer-to-peer content distribution network based on blockchain according to claim 9, characterized in that: The optimal distributor selection algorithm includes: First, choose a distribution budget that The distributor of all n ordered content block distribution tasks within ; Then if there is a remaining budget, add a cost performance The highest distributor, until the budget is exhausted, where Indicates other distributors Bid a fee for each ordered content block, Indicates other distributors comprehensive credibility.

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