Verifiable delay function-based online examination anti-cheating method, system and device, and storage medium

Abstract

The invention discloses an online examination anti-cheating method, system and device based on a verifiable delay function, and a storage medium, and is applied to a server, the method comprises the following steps: generating an initial challenge, and sending the initial challenge to a client; a data packet from the client is received, the data packet comprises an answer result and a VDF identifier, and the VDF identifier is obtained by using the initial challenge as input and running a VDF algorithm at the client; verifying the VDF identifier to verify whether the answering process accords with the specified delay time so as to determine whether the examinee has a cheating behavior; by verifying the VDF identifier, the answer process of each examinee is ensured to accord with the specified delay time, and the fairness and fairness of the examination are ensured.

Description

Technical Field

[0001] The present invention relates to the field of computer technology, and in particular to an online examination anti-cheating method, system, device and storage medium based on a verifiable delay function. Background Art

[0002] With the popularization of the Internet, online examinations are becoming more common. There are many existing online examination anti-cheating methods, and their counting principles and workflows are different, but they can be roughly divided into several categories: time-based monitoring, behavior-based analysis, and technical means-based prevention.

[0003] Current monitoring methods are prone to problems with inaccurate time control. For example, network delays may affect the accuracy of the timer, and differences in network environments among different candidates may cause the timer to display inconsistent times, which in turn affects the fairness of the exam. For example, candidates may cheat by completing the exam early or passing on answers. Summary of the invention

[0004] In order to ensure that each candidate's answering process complies with the prescribed delay time and to ensure the fairness and impartiality of the examination, this application provides an online examination anti-cheating method based on a verifiable delay function.

[0005] On the one hand, a method for preventing cheating in online examinations based on a verifiable delay function is provided, which is applied to a server, and the method comprises:

[0006] Generate an initial challenge and send it to the client;

[0007] Receiving a data packet from the client, the data packet including a question answering result and a VDF identifier, wherein the VDF identifier is obtained by running a VDF algorithm on the client using the initial challenge as input;

[0008] Verify the VDF identifier to verify whether the answering process complies with the prescribed delay time to determine whether the examinee has cheated.

[0009] In an optional implementation, generating the initial challenge includes:

[0010] A random number is generated as the initial challenge, where the random number is generated based on a current timestamp or other unique identifier.

[0011] In an optional embodiment, the method further includes:

[0012] Scoring according to the answer results and recording the scoring results;

[0013] Feedback the scoring result to the client;

[0014] The data during the examination is archived, saved and backed up, wherein the data during the examination includes the answer results and the VDF identifier.

[0015] In an optional implementation, the verifying the VDF identifier to determine whether the examinee has cheated includes:

[0016] If the VDF identifier is verified, the step of feeding back the scoring result to the client is triggered; otherwise,

[0017] Determine that the examinee has engaged in cheating behavior and mark the cheating behavior.

[0018] In an optional implementation, before generating the initial challenge and sending it to the client, the method further includes:

[0019] Determine the type of VDF algorithm to be used based on the algorithm’s calculation time and verification time;

[0020] Set the parameters of the VDF algorithm;

[0021] Perform preliminary testing using the parameters to determine whether the computation time and verification time of the VDF algorithm meet expectations;

[0022] If not, adjust the parameters according to the result of the preliminary test until the calculation time and the verification time meet expectations.

[0023] In an optional implementation, setting the parameters of the VDF algorithm includes:

[0024] Determine the target time based on the actual duration of the exam and network latency;

[0025] Determining the number of iterations in the VDF algorithm so that the computation time is close to the target time;

[0026] The adjusting the parameters according to the result of the preliminary test comprises:

[0027] If the calculation time is too short, increase the number of iterations; if the verification time is too long, reduce the difficulty factor of the VDF algorithm.

[0028] On the other hand, there is also provided an anti-cheating method for online examinations based on a verifiable delay function, which is applied to a client, and the method comprises:

[0029] Receive the initial challenge from the server and start the local computation process;

[0030] Using the initial challenge as input, running the VDF algorithm to calculate a VDF identifier;

[0031] After the examinee starts answering the questions, record the answering time and the answering process;

[0032] After completing the test, the examinee submits the VDF identifier together with the test result to the server. The VDF identifier is used by the server for verification to verify whether the test-taking process complies with the prescribed delay time to determine whether the examinee has cheated.

[0033] On the other hand, an online examination anti-cheating system is provided, including an identity authentication module, an initial challenge generation module, a VDF calculation module, a VDF verification module, an answer management module, a score processing module and a system monitoring and alarm module, wherein:

[0034] The identity verification module is used to verify the identity of the examinee;

[0035] The initial challenge generation module is used to generate a unique initial challenge for the client before the exam begins, and the initial challenge is used in the VDF calculation process;

[0036] The VDF calculation module is used to receive the initial challenge, execute the VDF algorithm, and generate a VDF identifier;

[0037] The answer management module is used to manage the answer process of the examinee and submit the answer result together with the VDF identifier to the VDF verification module;

[0038] The VDF verification module is used to verify the VDF identifier to verify whether the answering process complies with the prescribed delay time to determine whether the examinee has cheated;

[0039] The score processing module is used to process the answer results, record them in the system and feed them back to the client;

[0040] The system monitoring and alarm module is used to monitor the system operation status and issue an alarm when an abnormality occurs in the system.

[0041] On the other hand, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the aforementioned online exam anti-cheating method based on a verifiable delay function and any possible implementation method thereof.

[0042] On the other hand, a computer storage medium is provided, which stores one or more instructions, and the one or more instructions are suitable for being loaded by a processor and executing the steps of the above-mentioned online examination anti-cheating method based on a verifiable delay function and any possible implementation method thereof.

[0043] The application generates an initial challenge through a server and sends it to a client; receives a data packet from the client, the data packet includes an answer result and a VDF identifier, and the VDF identifier is obtained by running a VDF algorithm on the client using the initial challenge as input; verifies the VDF identifier to verify whether the answering process complies with the specified delay time to determine whether the candidate has cheated; by verifying the VDF identifier, it can be ensured that the answering process of each candidate complies with the specified delay time, thereby ensuring the fairness and impartiality of the examination, and there is no need to rely on a single central server for verification, thereby improving verification efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0045] Figure 1 A flowchart of an online exam anti-cheating method based on a verifiable delay function provided in an embodiment of the present application;

[0046] Figure 2 A flowchart of another online examination anti-cheating method based on a verifiable delay function provided in an embodiment of the present application;

[0047] Figure 3 A schematic diagram of interaction between a server and a client provided in an embodiment of the present application;

[0048] Figure 4 A schematic diagram of the structure of an online examination anti-cheating system provided in an embodiment of the present application;

[0049] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0051] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0052] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0053] The Verifiable Delay Function (VDF) mentioned in the embodiments of this application is a mathematical function that requires at least a known period of time to calculate the function, even when a small number of CPUs are used for parallel calculations. VDF usually accepts an input and some parameters (security parameters, time parameters, etc.), outputs a result and a corresponding proof, and the verifier will judge whether the result of the VDF is correct based on the input, parameters, output and result.

[0054] VDF satisfies the following properties: the verification of the results is very efficient, unique (for any VDF input, there should be a unique output result that can pass the verification), and seriality (even if the attacker can calculate a long time in advance and has many parallel processors, the probability of using various calculation methods to calculate the VDF result in less than the predetermined time can be negligible).

[0055] The use of a verifiable delay function (VDF) to prevent cheating in the embodiments of the present application mainly relies on several key characteristics of VDF: the non-parallelism of calculations, the verifiability of results, and the provability of time delays.

[0056] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0057] See also Figure 1 , Figure 1 is a flow chart of an online examination anti-cheating method based on a verifiable delay function provided in an embodiment of the present application, such as Figure 1 As shown, the method can be applied to a server, and the method may include:

[0058] 101. Generate an initial challenge and send it to the client;

[0059] 102. Receive a data packet from the client, the data packet including the answer result and a VDF identifier, the VDF identifier being obtained by running a VDF algorithm on the client using the initial challenge as input;

[0060] 103. Verify the above VDF identifier to verify whether the answering process complies with the prescribed delay time to determine whether the candidate has cheated.

[0061] The method in the embodiment of the present application is mainly executed by the server. When taking an online test, the candidate can answer questions through the client (terminal device), and the server can communicate with the client to send test questions, receive answer results, test operation data, etc.

[0062] The server needs to be able to verify the VDF identifier and handle a large number of concurrent requests. During the entire process, appropriate security measures need to be taken to prevent the VDF identifier from being tampered with or leaked.

[0063] In an optional implementation, the generating of the initial challenge includes:

[0064] Generate a random number as the initial challenge, where the random number is generated based on a current timestamp or other unique identifier.

[0065] Specifically, at the beginning of the test, the server can generate an initial challenge and send it to the client. The system can generate a random number as the initial challenge, and the random number can be generated based on the current timestamp or other unique identifier.

[0066] Each candidate's client receives this initial challenge and begins the local computation process.

[0067] After the candidate's client receives the initial challenge, it can use the VDF algorithm to calculate a unique identifier, namely the VDF identifier. The calculation process requires a fixed time delay, which can be set according to the specific requirements of the exam, such as 5 minutes.

[0068] After the candidate starts answering the questions, he / she can record the answering time and the answering process; after the candidate finishes answering the questions, the client submits the calculated VDF identifier together with the answering result to the server.

[0069] Running the VDF algorithm in the embodiment of this application mainly includes two aspects:

[0070] The first is to calculate the VDF identifier: the candidate's client uses the initial challenge as input, runs the VDF algorithm, and calculates a unique identifier;

[0071] The second is waiting for the target time: candidates need to wait for the target time specified by the VDF algorithm and cannot complete the exam in advance during this period.

[0072] In an optional implementation, the above method further includes:

[0073] Score the answers based on the above questions and record the score results;

[0074] Feedback the above-mentioned scoring results to the above-mentioned client;

[0075] The data during the examination is archived, saved and backed up, wherein the data during the examination includes the answer results and the VDF identifier.

[0076] The server can score each candidate's answer and record it in the system, and can also feed back the test results and related information to the candidate.

[0077] Post-processing can also include data archiving, which mainly involves archiving all data during the exam (including VDF identifiers, answer results, etc.), and regularly backing up data to a safe place to prevent data loss.

[0078] The server in the embodiment of the present application has a VDF verification function, which can verify the VDF identifier submitted by the candidate to ensure that its calculation process meets the expected delay time.

[0079] In an optional implementation, the verification of the VDF identifier to determine whether the examinee has cheated includes:

[0080] If the above VDF identifier is verified, the step of feeding back the above scoring result to the above client is triggered; otherwise,

[0081] Determine if the examinee has engaged in cheating and mark the cheating behavior.

[0082] Specifically, after the examinee submits the answer, the server verifies whether the VDF identifier is correct. The verification process takes a short time and can be completed quickly. If the verification is successful, it means that the examinee's answering process meets the expected time; otherwise, it is considered that cheating may have occurred. Here, the client and / or the examinee can be marked as cheating.

[0083] Optionally, in order to better perform the method in the embodiment of the present application, the method further includes the step of preparing the examination environment, which may mainly include:

[0084] Ensure that the test platform can support the operation of the VDF algorithm;

[0085] Test before the exam to ensure that the VDF algorithm can generate VDF identifiers within the expected time and that the verification process is efficient. Specific test objectives can be set and adjusted as needed.

[0086] Through the above steps, cheating in online exams can be effectively prevented, ensuring that each candidate completes the exam under fair conditions. The role of the VDF algorithm includes ensuring that each candidate's answering process requires a fixed time delay, thereby avoiding the situation of gaining an unfair advantage by speeding up the answering process.

[0087] In an optional implementation, before the above step 101, the above method further includes:

[0088] Determine the type of VDF algorithm to be used based on the algorithm’s calculation time and verification time;

[0089] Set the parameters of the VDF algorithm;

[0090] Perform preliminary tests using the above parameters to determine whether the computation time and verification time of the above VDF algorithm are in line with expectations;

[0091] If not, adjust the above parameters according to the results of the above preliminary test until the above calculation time and the above verification time meet expectations.

[0092] Specifically, we first need to determine the VDF algorithm type and design the VDF parameters.

[0093] The target time in the embodiment of the present application mainly refers to the expected time required for each candidate to complete the test. The basis for selecting VDF parameters is to ensure that its calculation time is close to the target time.

[0094] Further optionally, the above-mentioned setting of the parameters of the VDF algorithm includes:

[0095] Determine the target time based on the actual duration of the exam and network latency;

[0096] Determine the number of iterations in the VDF algorithm so that the calculation time is close to the target time;

[0097] The above parameters are adjusted according to the results of the above preliminary tests, including:

[0098] If the above calculation time is too short, increase the above iteration number; if the above verification time is too long, reduce the difficulty factor of the above VDF algorithm.

[0099] In the embodiment of the present application, the target time can be determined according to the actual duration of the test to ensure that each candidate's answering process requires a fixed time delay. Optionally, factors such as network delay can also be considered for adjustment. In addition, the number of iterations in the VDF algorithm needs to be set so that the calculation time is close to the above target time; and an appropriate difficulty factor needs to be selected to ensure that the calculation process cannot be shortened by increasing computing resources. The parameter settings involved can be adjusted as needed, and the embodiment of the present application does not limit this.

[0100] Selecting an appropriate VDF algorithm and its parameters is one of the key steps to ensure the effectiveness of the VDF-based online exam anti-cheating method. The following is a specific embodiment for selecting an appropriate VDF algorithm and its parameters:

[0101] 1. Choose a VDF algorithm

[0102] 1) Study existing VDF algorithms

[0103] Research background: First, understand the existing VDF algorithms, such as Pietrzak's VDF, Boneh et al.'s VDF, etc.

[0104] Compare advantages and disadvantages: Evaluate the performance, security, implementation difficulty and other factors of each algorithm, and select the algorithm that best suits the test scenario.

[0105] 2) Evaluate algorithm performance

[0106] Computational complexity: Evaluate the computational complexity of the algorithm to ensure that the time required for calculation is close to the target time.

[0107] Verification efficiency: Evaluate the speed of the verification process to ensure that verification does not take too long.

[0108] 3) Test the algorithm

[0109] Prototyping: Develop a prototype of the algorithm and test its performance in a real environment.

[0110] Performance testing: Test the performance of the algorithm in a simulated environment, including computation time and verification time.

[0111] 2. Set VDF parameters

[0112] 1) Determine the target time

[0113] Exam duration: Determine the target time based on the actual duration of the exam to ensure that each candidate's answering process requires a fixed time delay.

[0114] Safety margin: Taking into account factors such as network delay, a certain safety margin can be added to the target time.

[0115] 2) Select parameter values

[0116] Iterations: Determine the number of iterations in the VDF algorithm so that the computation time is close to the target time.

[0117] Difficulty Factor: Choose an appropriate difficulty factor to ensure that the computational process cannot be shortened by increasing computational resources.

[0118] 3) Parameter adjustment

[0119] Preliminary test: Perform preliminary tests with the selected parameters to see whether the calculation time and verification time are in line with expectations.

[0120] Fine-tune parameters: Adjust parameters based on preliminary test results until both the calculation time and verification time meet the requirements.

[0121] 3. Experimental Verification

[0122] 1) Experimental design

[0123] Test environment: Build a test environment to simulate real exam scenarios.

[0124] Experimental samples: Select a certain number of test samples for the experiment to ensure that the samples are representative.

[0125] 2) Experimental execution

[0126] Calculation process: record the calculation time of each test sample under different parameter settings.

[0127] Verification process: Record the time spent verifying each test sample.

[0128] Statistical analysis: Perform statistical analysis on the experimental data to evaluate the consistency and stability of the algorithm performance.

[0129] 3) Result evaluation

[0130] Computation time consistency: Evaluate whether the computation time is consistent across test samples to ensure that each candidate requires the same time delay to answer the questions.

[0131] Reasonableness of verification time: Evaluate whether the verification time is reasonable and ensure that the verification process does not affect the overall performance of the system.

[0132] 4. Parameter Optimization

[0133] 1) Parameter optimization strategy

[0134] Iterative optimization: Continuously adjust parameters based on experimental results until both calculation time and verification time meet the requirements.

[0135] Performance balance: Find the best balance between computing time and verification time to ensure that the system is both safe and efficient.

[0136] 2) Actual deployment

[0137] Pre-release testing: Pre-release testing is performed before formal deployment to ensure that the system performs as expected in the real environment.

[0138] Monitoring and adjustment: Continue to monitor performance indicators after the system goes online and adjust parameters based on actual conditions.

[0139] 5. Security considerations

[0140] 1) Safety assessment

[0141] Attack simulation: Simulate possible attack scenarios to evaluate the security of the VDF algorithm.

[0142] Anti-quantum attack: Consider the future threat of quantum computing and choose a VDF algorithm that is resistant to quantum attacks.

[0143] 2) Security Updates

[0144] Regular review: Regularly review the security of the VDF algorithm to ensure that the algorithm will not become invalid due to new attack methods.

[0145] Update strategy: Develop a security update strategy to respond to emerging security threats in a timely manner.

[0146] For example, suppose Pietrzak's VDF algorithm is selected and the target time is determined to be 5 minutes.

[0147] The following is the specific algorithm design process:

[0148] 1. Determine the target time: The target time is 5 minutes.

[0149] 2. Select parameter values: Initially select the number of iterations as (n) and the difficulty factor as (d).

[0150] 3. Preliminary testing: Use preliminary parameter values ​​for testing and record the calculation time and verification time.

[0151] 4. Adjust parameters: If the calculation time is too short, increase the number of iterations; if the verification time is too long, reduce the difficulty factor.

[0152] 5. Experimental verification: Test the adjusted parameter values ​​multiple times to ensure that the calculation time and verification time meet the requirements.

[0153] 6. Safety assessment: Evaluate whether the adjusted parameter values ​​meet safety requirements.

[0154] 7. Actual deployment: Test the adjusted parameter values ​​in a pre-release environment to ensure stable system operation.

[0155] See also Figure 2 , Figure 2 A flowchart of another online exam anti-cheating method based on a verifiable delay function provided in an embodiment of the present application is shown in FIG. Figure 2 As shown, the method is applied to a client, and the method includes:

[0156] 201. Receive the initial challenge from the server and start the local computing process;

[0157] 202. Using the above initial challenge as input, run the VDF algorithm to calculate and obtain the VDF identifier;

[0158] 203. After the examinee starts answering the questions, he / she shall record the time and process of answering the questions;

[0159] 204. After completing the test, the candidate submits the VDF identifier together with the test result to the server. The VDF identifier is used by the server for verification to verify whether the test process complies with the prescribed delay time to determine whether the candidate has cheated.

[0160] The method in the embodiment of the present application can be executed by the client, and in a specific scenario, can be executed on the client of the examinee. The client software or browser plug-in used by the examinee needs to support the VDF algorithm and be able to perform calculations securely.

[0161] Among them, the method steps executed by the above client are Figure 1 The above has been described in the illustrated embodiment and will not be described again here.

[0162] The online exam anti-cheating method in the embodiment of the present application utilizes a verifiable delay function, which is a special type of function designed to require a fixed, verifiable time delay to calculate the output of the function. This time delay is inherent in the calculation process and cannot be shortened by increasing computing resources. Therefore, VDF can be used as an effective mechanism to ensure fairness in online exams and prevent cheating.

[0163] This application is based on a verifiable delay function (VDF) to prevent cheating in online exams, which can mainly solve the following problems:

[0164] 1. Exam fairness: Ensure that each candidate completes the exam in the same amount of time to prevent unfairness caused by time differences.

[0165] 2. Prevent cheating: Prevent candidates from cheating by completing the test early or passing answers to each other.

[0166] 3. Time control: Ensure that each candidate's answering process requires a fixed time delay to prevent unfair advantages from being gained by speeding up the answering process.

[0167] In addition, the VDF algorithm is also irreversible, that is, the calculation process takes a certain amount of time, but the verification process is relatively fast. Through the method in the embodiment of the present application, it can be ensured that cheaters cannot bypass the time delay requirement by pre-calculating the identifier, while quickly verifying the correctness of the identifier.

[0168] The VDF algorithm also has decentralized characteristics and can be used in a decentralized environment. It can verify time delays even without a central server. In a distributed examination environment, the fairness of the examination can still be guaranteed without relying on a single central server for verification.

[0169] Figure 3 Schematic diagram of the interaction between the server and the client in the embodiment of the present application.

[0170] Based on the description of the above method embodiment, the embodiment of the present application also discloses an online examination anti-cheating system.

[0171] Figure 4 A schematic diagram of the structure of an online examination anti-cheating system provided in an embodiment of the present application is shown in FIG. Figure 4 As shown, the online examination anti-cheating system 400 includes an identity authentication module 410, an initial challenge generation module 420, a VDF calculation module 430, a VDF verification module 440, a question management module 450, a score processing module 460 and a system monitoring and alarm module 470, wherein:

[0172] The identity verification module 410 is used to verify the identity of the examinee;

[0173] The initial challenge generation module 420 is used to generate a unique initial challenge for the client before the test begins. The initial challenge is used in the VDF calculation process.

[0174] The VDF calculation module 430 is used to receive the initial challenge, execute the VDF algorithm, and generate a VDF identifier;

[0175] The answer management module 450 is used to manage the answer process of the examinee and submit the answer result together with the VDF identifier to the VDF verification module 440;

[0176] The VDF verification module 440 is used to verify the VDF identifier to verify whether the answering process complies with the prescribed delay time to determine whether the examinee has cheated;

[0177] The score processing module 460 is used to process the answer results, record them in the system and feed them back to the client;

[0178] The system monitoring and alarm module 470 is used to monitor the system operation status and issue an alarm when an abnormality occurs in the system.

[0179] Specifically, the identity verification module 410 can verify the identity of the examinee through username / password, biometrics (such as fingerprint, facial recognition), multi-factor authentication, etc. When the examinee logs into the system, the identity verification module first verifies the examinee's identity. If the verification is successful, the examinee is allowed to enter the test preparation stage; otherwise, access is denied.

[0180] The initial challenge generation module 420 can generate a unique initial challenge (such as a random number) for each candidate before the exam begins, and send it to the VDF calculation module. The challenge is used in the subsequent VDF calculation process. At the same time, the module also notifies the answer management module 450 that the exam is about to begin.

[0181] The VDF calculation module 430 can receive the initial challenge, execute the VDF algorithm, generate a unique identifier, and ensure that the calculation process requires a fixed time delay. After the candidate client receives the initial challenge, the VDF calculation module 430 starts to calculate the VDF identifier. After the candidate completes the answer, the VDF calculation module 430 submits the calculation result (VDF identifier) ​​together with the answer result to the VDF verification module 440.

[0182] The answer management module 450 can manage the candidate's answering process, including answering time control, etc., can monitor the candidate's answering progress, and record the answering time. Specifically, after the candidate starts answering, the answer management module records the answering start time, and when the answering is completed, the answer management module records the answering end time, and submits the answer result together with the VDF identifier to the VDF verification module 440.

[0183] The VDF verification module 440 can verify the VDF identifier submitted by the examinee to ensure that its calculation process meets the expected time and prevent cheating. The VDF verification module 440 can verify whether the identifier is correct. If the verification is passed, the answer result is forwarded to the score processing module; otherwise, it is marked as cheating.

[0184] The score processing module 460 receives the answer results verified by VDF, scores the answer results, records the scores in the system, and finally feeds back the test scores to the candidates.

[0185] The system monitoring and alarm module 470 is mainly used to monitor the system operation status, ensure the stable operation of the system, and issue an alarm in time when an abnormality occurs in the system.

[0186] The system monitoring and alarm module 470 can continuously monitor the system operation status, such as server load, network connection status, etc. If an abnormality is found, the administrator is notified in time and the alarm information is recorded.

[0187] Optionally, the online examination anti-cheating system 400 further includes:

[0188] The log and audit module 480 is used to:

[0189] Record all important events during the exam for later audit.

[0190] Provides logging function to record candidates' operations and key status changes of the system.

[0191] Specifically, the log and audit module 480 can record key events during the examination, such as login, start of the test, end of the test, etc. These logs can be used for subsequent audits to ensure the transparency and traceability of the examination process.

[0192] Optionally, the online examination anti-cheating system 400 also includes a user interface module 490, which can provide a friendly user interface to facilitate candidates to log in, answer questions and other operations, and can also display examination-related information, such as remaining time, precautions, etc.

[0193] Specifically, the user interface module 490 interacts with the identity authentication module 410, the question answering management module 450, etc., displays the information required by the examinees, and guides the examinees to successfully complete the examination process through a friendly interface.

[0194] based on Figure 3 and Figure 4 As shown, the following example is described:

[0195] Suppose you are designing an online exam system that needs to ensure that each candidate completes the exam in the same amount of time and prevent candidates from passing answers to each other. You can achieve this goal by following the steps below:

[0196] 1. System architecture functional modules

[0197] Identity verification module: responsible for verifying the identity of candidates.

[0198] Initial challenge generation module: Generates the initial challenge for VDF calculation.

[0199] VDF calculation module: executes the VDF algorithm to calculate a unique identifier.

[0200] Answering management module: manage the answering process of candidates.

[0201] VDF verification module: Verifies the VDF identifier submitted by the candidate.

[0202] Score processing module: processes the test takers’ answer results.

[0203] 2. Implementation process

[0204] 2.1 Authentication

[0205] Function: Verify the identity of candidates and ensure that only legitimate candidates can take the exam.

[0206] Implementation: After the candidate logs into the system, the system verifies the candidate's identity through the username and password. Biometric technology (such as fingerprint and facial recognition) can be combined to further enhance the security of identity verification.

[0207] 2.2 Initial Challenge Generation

[0208] Function: Generates a unique initial challenge for each candidate at the beginning of the exam.

[0209] Implementation: At the beginning of the exam, the system generates a random number as the initial challenge and sends it to each candidate. This random number can be generated based on the current timestamp or other unique identifier.

[0210] 2.3 VDF Calculation

[0211] Function: Use the initial challenge as input, execute the VDF algorithm, and calculate a unique identifier.

[0212] Implementation: After receiving the initial challenge, the candidate client uses the VDF algorithm to calculate a unique identifier. The calculation process requires a fixed time delay, which can be set according to the specific requirements of the exam, such as 5 minutes.

[0213] 2.4 Question management

[0214] Function: Manage the test-taking process of candidates, including time control, etc.

[0215] Implementation: After the candidate starts answering the questions, the system records the answering time and process. After the candidate finishes answering the questions, he / she submits the calculated VDF identifier together with the answer result to the system.

[0216] 2.5 VDF Verification

[0217] Function: Verify the VDF identifier submitted by the candidate to ensure that its calculation process meets the expected time.

[0218] Implementation: After the candidate submits the answer, the system verifies whether the VDF identifier is correct. The verification process takes a short time and can be completed quickly. If the verification is passed, it means that the candidate's answering process meets the expected time; otherwise, there may be cheating.

[0219] 2.6 Score Processing

[0220] Function: Process the test takers' answers and record them in the system.

[0221] Implementation: After the VDF verification is passed, the system processes the candidate's answer results and records them in the system. The final score is fed back to the candidate.

[0222] Based on the description of the above method embodiment, the present application embodiment also provides an electronic device. Figure 5 The electronic device 500 at least includes a processor 501, an input device 502, an output device 503, and a computer storage medium 504. The processor 501, the input device 502, the output device 503, and the computer storage medium 504 in the electronic device may be connected via a bus or other means.

[0223] The electronic device 500 in the embodiment of the present application may be a server or a terminal device. The computer storage medium 504 may be stored in the memory of the electronic device, and the computer storage medium 504 is used to store a computer program, and the computer program includes program instructions, and the processor 501 is used to execute the program instructions stored in the computer storage medium 504. The processor 501 (or CPU (Central Processing Unit)) is the computing core and control core of the electronic device, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement corresponding method flows or corresponding functions; in one embodiment, the processor 501 in the embodiment of the present application may be used to perform a series of processing, including such as Figure 1 The method steps in the embodiment shown, or as Figure 2 The method steps etc. in the illustrated embodiments.

[0224] The embodiment of the present application also provides a computer storage medium (Memory), which is a memory device in an electronic device for storing programs and data. It is understandable that the computer storage medium here can include both built-in storage media in electronic devices and, of course, extended storage media supported by electronic devices. The computer storage medium provides a storage space that stores the operating system of the electronic device. In addition, one or more instructions suitable for being loaded and executed by the processor 501 are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer storage medium here can be a high-speed RAM memory, or a non-volatile memory, such as at least one disk storage; optionally, it can also be at least one computer storage medium located away from the aforementioned processor.

[0225] In one embodiment, the processor 501 may load and execute one or more instructions stored in a computer storage medium to implement the corresponding steps in the above embodiment; in a specific implementation, the processor 501 may load and execute one or more instructions in a computer storage medium as follows: Figure 1 The method steps performed by the application program in the embodiment shown, or Figure 2 The method steps and the like executed by the device in the illustrated embodiment will not be described in detail here.

[0226] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0227] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the division of the module is only a logical function division, and there may be other division methods in actual implementation, for example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. The mutual coupling, direct coupling, or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0228] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0229] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more available media integrations. The available medium may be a read-only memory (ROM), or a random access memory (RAM), or a magnetic medium, such as a floppy disk, a hard disk, a tape, a magnetic disk, or an optical medium, such as a digital versatile disc (DVD), or a semiconductor medium, such as a solid state disk (SSD), etc.

Claims

1. An anti-cheating method for online examinations based on a verifiable delay function, characterized in that: Applied to a server, the method comprises: Generate an initial challenge and send it to the client; Receiving a data packet from the client, the data packet including a question answering result and a VDF identifier, wherein the VDF identifier is obtained by running a VDF algorithm on the client using the initial challenge as input; Verify the VDF identifier to verify whether the answering process complies with the prescribed delay time to determine whether the examinee has cheated.

2. The method according to claim 1, characterized in that The generating of the initial challenge comprises: A random number is generated as the initial challenge, where the random number is generated based on a current timestamp or other unique identifier.

3. The method according to claim 1, characterized in that The method further comprises: Scoring according to the answer results and recording the scoring results; Feedback the scoring result to the client; The data during the examination is archived, saved and backed up, wherein the data during the examination includes the answer results and the VDF identifier.

4. The method according to claim 3, characterized in that The verifying the VDF identifier to determine whether the examinee has cheated includes: If the VDF identifier is verified, the step of feeding back the scoring result to the client is triggered; otherwise, Determine that the examinee has engaged in cheating behavior and mark the cheating behavior.

5. The method according to claim 1, characterized in that Before generating the initial challenge and sending it to the client, the method further includes: Determine the type of VDF algorithm to be used based on the algorithm’s calculation time and verification time; Set the parameters of the VDF algorithm; Perform preliminary testing using the parameters to determine whether the computation time and verification time of the VDF algorithm meet expectations; If not, adjust the parameters according to the result of the preliminary test until the calculation time and the verification time meet expectations.

6. The method according to claim 5, characterized in that The parameters of the VDF algorithm are set, including: Determine the target time based on the actual duration of the exam and network latency; Determining the number of iterations in the VDF algorithm so that the computation time is close to the target time; The adjusting the parameters according to the result of the preliminary test comprises: If the calculation time is too short, increase the number of iterations; if the verification time is too long, reduce the difficulty factor of the VDF algorithm.

7. An anti-cheating method for online examinations based on a verifiable delay function, characterized in that: Applied to a client, the method comprises: Receive the initial challenge from the server and start the local computation process; Using the initial challenge as input, running the VDF algorithm to calculate a VDF identifier; After the examinee starts answering the questions, record the answering time and the answering process; After completing the test, the examinee submits the VDF identifier together with the test result to the server. The VDF identifier is used by the server for verification to verify whether the test-taking process complies with the prescribed delay time to determine whether the examinee has cheated.

8. An online examination anti-cheating system, characterized in that: It includes identity authentication module, initial challenge generation module, VDF calculation module, VDF verification module, answer management module, score processing module and system monitoring and alarm module, among which: The identity verification module is used to verify the identity of the examinee; The initial challenge generation module is used to generate a unique initial challenge for the client before the exam begins, and the initial challenge is used in the VDF calculation process; The VDF calculation module is used to receive the initial challenge, execute the VDF algorithm, and generate a VDF identifier; The answer management module is used to manage the answer process of the examinee and submit the answer result together with the VDF identifier to the VDF verification module; The VDF verification module is used to verify the VDF identifier to verify whether the answering process complies with the prescribed delay time to determine whether the examinee has cheated; The score processing module is used to process the answer results, record them in the system and feed them back to the client; The system monitoring and alarm module is used to monitor the system operation status and issue an alarm when an abnormality occurs in the system.

9. An electronic device, characterized in that: The invention comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the online examination anti-cheating method based on a verifiable delay function as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the processor executes the steps of the online examination anti-cheating method based on a verifiable delay function as described in any one of claims 1 to 7.

Images