Privacy security auction system based on national secret algorithm and dynamic bidding truncation method

Abstract

The invention belongs to the technical field of privacy protection, and discloses a privacy security auction system based on a national secret algorithm and a dynamic bidding truncation method, and the privacy security auction system comprises a key generation module, a ciphertext comparison module and an output module; according to the method, security comparison of homomorphic ciphertexts is realized by using the SM2 algorithm, so that the auction company can obtain the current highest auction price and the ciphertext of the identity information of the auction user on the basis of not knowing the auction price of the user. According to the scheme, the ciphertext comparison of the auction price can be realized, so that the privacy of the auction information is protected. In addition, the scheme can also solve the problem that the bidder submits the auction price at the moment when the auction system is closed in the online auction. Simulation experiment results show that the system is very efficient during multi-user security comparison.

Description

Technical Field

[0001] The present invention belongs to the field of privacy protection technology, and in particular relates to a privacy-safe auction system based on a national secret algorithm and a dynamic bidding truncation method. Background Art

[0002] The auction system is a widely used mechanism in business, government, and other fields for bidding on goods. Users bid on prices, and the highest bidder wins the auction. However, traditional auction systems present several potential security issues, primarily regarding the confidentiality of bidders' bids and the fairness of the bidding process. For example, when bids are not processed, auction companies can increase their revenue by forcibly raising prices (so-called "market manipulation"). Other bidders can also privately obtain competitors' bids and adjust their strategies accordingly to profit from the results. Furthermore, the transmission and storage of prices during the auction process can be subject to unauthorized access and tampering, compromising the transparency of the auction.

[0003] To address these issues, several solutions have been proposed and applied to traditional auction systems. For example, the blockchain-based secure auction protocol described in "Strain: A Secure Auction for Blockchains" uses Goldwasser-Micali encryption and zero-knowledge proofs to protect bid privacy, support collusion-resistant, and irrevocable bidding. Its core is a parallel two-party comparison mechanism. Other existing voting systems use public key cryptography to encrypt bid information and protect bidder identities. However, these solutions typically utilize internationally accepted encryption algorithms rather than the National Cryptography Algorithm (NCA), a cryptographic standard promoted in my country that provides highly secure data encryption and signing capabilities. Despite its widespread use in China, the NCA is rarely used in auction systems. Furthermore, the standard NCA does not support homomorphic operations, making the comparison protocol inoperable.

[0004] Through the above analysis, the problems and defects of the existing technology are as follows:

[0005] Relying on a semi-honest arbitrator (auctioneer) to verify the comparison results poses centralization risks, whereas a trusted key center achieves complete decentralization. Secondly, the paper uses an internationally accepted encryption algorithm rather than the National Cryptography (NCC) algorithm. The NCC is a cryptographic standard promoted in my country, designed to provide highly secure data encryption and signing capabilities. Although the NCC algorithm is widely used in China, it is rarely used in auction systems. Furthermore, the standard NCC algorithm does not support homomorphic operations, making the comparison protocol unusable. Summary of the Invention

[0006] In response to the problems existing in the prior art, the present invention provides a privacy-secure auction system and a dynamic bidding truncation method based on a national secret algorithm.

[0007] The present invention is implemented as follows: a privacy-safe auction system based on a national secret algorithm includes:

[0008] Key generation module, ciphertext comparison module, output module;

[0009] The key generation module is connected to the ciphertext comparison module and the output module, and is used by the trusted key center to randomly select public keys and private keys. The public key is used for encryption between the server and the user, and the private key is used for decryption by the trusted key center.

[0010] The ciphertext comparison module is connected to the key generation module and the output module. The server sends the encrypted current reserve price and identity information to the user. The user encrypts his / her own reserve price and identity information, performs ciphertext comparison, and sends the ciphertext comparison result to the server.

[0011] The output module is connected to the key generation module and the ciphertext comparison module. After the server receives the comparison result, it determines whether all users have participated in the comparison. If not, it will update the current reserve price and identity information and repeat the ciphertext comparison. If so, it will request the trusted key center to decrypt it and output the final reserve price and corresponding identity information.

[0012] Furthermore, the ciphertext comparison module:

[0013] The SM2 algorithm used in the ciphertext comparison constructs a public key encryption with additive homomorphic properties. First, the standard SM2 scheme is part c2 and part is Where t = KDF(x2||y2,mlen), KDF: {0,1} * ×mlen→{0,1} mlen , whereas in this scheme, there is no need to calculate t; secondly, the standard SM2 scheme supports message integrity verification.

[0014] Furthermore, the public key encryption with additive homomorphic properties is constructed based on the SM2 algorithm:

[0015] User B randomly selects a private key Public key pk = [sk]G; the encryption process is as follows. Suppose the message m sent by user A to user B is m. User A needs to perform the following calculation steps:

[0016] 1) Generate random numbers

[0017] 2) Calculate the elliptic curve point c1 = [k]G = (x1, y1), [k]pk = (x2, y2)

[0018] 3) Calculate the elliptic curve point S = [h]pk. If S = O, report an error and exit.

[0019] 4) Calculate c2 = [m]G + [k]pk

[0020] 5) Calculate c3 = H(x2||m||y2)

[0021] 6) Output ciphertext c = (c1, c2, c3) and send it to user B via a secure channel;

[0022] The decryption process is as follows: User B receives the ciphertext c = (c1, c2, c3) sent by User A. User B then needs to perform the following calculation steps:

[0023] 1) Get c1 from the ciphertext and verify whether it satisfies the elliptic curve equation. If not, report an error and exit;

[0024] 2) Calculate the elliptic curve point S = [h]c1. If S = O, report an error and exit;

[0025] 3) Calculate the elliptic curve point [sk]c1=(x2, y2)

[0026] 4) Calculate [m]G = c2 - [sk]c1

[0027] 5) Determine whether [m]G is the identity element. If so, restore m=0; otherwise, m=1

[0028] 6) Calculate u = H(x2||m||y2) and determine whether u = c3. If so, output the plaintext m, decryption is complete, and exit; otherwise, report an error and exit.

[0029] Furthermore, when there is a single user interacting with the server, the security protocol can be directly called. When multiple users interact with the server, that is, assuming there are n users, the security comparison protocol is called first. Then, when the current highest price and the user's identity information are obtained, it is determined whether the user is the last one. If so, the trusted key center is requested to decrypt it, and finally the highest price of the auction and the corresponding user's identity information are output. If not, the process returns to the first step and the security comparison protocol is called again until the last user is reached.

[0030] Furthermore, the specific steps of the key generation module are: the trusted key center randomly selects the private key Public key pk = [sk] G; the public key is used for encryption between the server and the user, and the private key is used for decryption by the trusted key center;

[0031] The specific steps of the ciphertext comparison module are as follows: the server uses the public key to encrypt the reserve price and its own identity information and sends the encrypted result to the user; after receiving the encrypted information, the user selects a random number to hide the comparison result and encrypts the price and identity information using the public key; the user calculates the ciphertext form of the comparison result and sends it to the server via a secure channel;

[0032] Furthermore, the specific steps of the output module are: after the server receives the ciphertext of the comparison result sent by the user, it determines whether all users have participated in the comparison. If not, it updates the current reserve price and identity information and repeats the ciphertext comparison. If so, it requests the trusted key center to decrypt it and output the final reserve price and corresponding identity information.

[0033] Another object of the present invention is to provide a dynamic bidding truncation method comprising:

[0034] Step 1: The key generation module uses the trusted key center to randomly select a public key and a private key. The public key is used for encryption between the server and the user, and the private key is used for decryption by the trusted key center.

[0035] Step 2: The encrypted current reserve price and identity information are sent to the user by the server through the ciphertext comparison module. The user encrypts his / her own reserve price and identity information, performs ciphertext comparison, and sends the ciphertext comparison result to the server.

[0036] Step 3: After receiving the comparison result from the server, the output module determines whether all users have participated in the comparison. If not, the current reserve price and identity information will be updated and the ciphertext comparison will be repeated. If so, the trusted key center will be requested to decrypt it and output the final reserve price and corresponding identity information.

[0037] Another object of the present invention is to provide a computer device, comprising 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 dynamic bidding truncation method.

[0038] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to execute the steps of the dynamic bidding truncation method.

[0039] Another object of the present invention is to provide an information data processing terminal, which is used to implement the privacy and security auction system based on the national secret algorithm.

[0040] In combination with the above technical solutions and the technical problems solved, please analyze the advantages and positive effects of the technical solutions to be protected by the present invention from the following aspects:

[0041] First, in view of the technical problems existing in the above-mentioned prior art and the difficulty of solving these problems, this paper closely combines the technical solutions to be protected by the present invention and the results and data during the research and development process, and analyzes in detail and in depth how the technical solutions of the present invention solve the technical problems and some creative technical effects brought about by solving the problems. The specific description is as follows:

[0042] This patent proposes a secure auction scheme based on the national secret SM2 encryption algorithm. This scheme utilizes the SM2 algorithm to achieve secure comparison of homomorphic ciphertexts, allowing auction companies to obtain the current highest bid and the ciphertext of the bidder's identity information without knowing the user's bid price. Furthermore, this scheme addresses the issue of bidders submitting bids in online auctions at the moment the auction system is closed. Therefore, this patent not only improves the security and credibility of auctions, but also ensures the confidentiality of bids, the fairness of the bidding process, and the transparency of results, reducing potential risks. It also promotes the application and development of domestic cryptographic technology.

[0043] This invention can solve technical problems in existing auction systems. For example, in traditional solutions, the user's highest bid and identity information are easily leaked due to the use of plain text to process auction prices; over-reliance on centralized auction companies as trusted third parties poses the risk of single-point data tampering or internal malicious activities; although general privacy computing technology can encrypt data, it is inefficient and cannot meet the high concurrency requirements of real-time bidding; the strong correlation between bidder identity and bid price can be easily reversed by attackers, exposing business strategies; and compliance defects caused by reliance on non-national secret algorithms.

[0044] To address the above issues, this solution builds a security architecture based on the national secret SM2 algorithm, which allows for ciphertext comparison and coordinated permissions. The server stores the identity information and ciphertext of the current highest bidder. After the auction, the highest price and its user's identity information are restored through the private key of the key center. The cooperation and interaction between the trusted key center, the server, and the bidding users form a comprehensive auction mechanism, which solves the problems of information protection and credibility in traditional auction systems. By modifying the national secret algorithm to encryption with homomorphic properties, the confidential comparison of bidding prices and the blind selection of the highest price are realized. The independent permissions of the auction company are constrained by a multi-party collaborative agreement. The identity-price association is blocked by combining layered anonymous identification. While ensuring the compliance of domestic cryptography, a trustworthy, efficient, and leak-resistant auction privacy protection system is reconstructed.

[0045] After modification and optimization, the design was based on the national secret algorithm with homomorphic encryption properties, and a secure auction system was implemented through code programming. The system has the feature of dynamic bidding truncation, which ensures that during the bidding process, the bidding range can be dynamically adjusted under the premise of ensuring data security and privacy protection, so as to improve the fairness and efficiency of the auction. The designed system was tested in detail and real cases were analyzed to verify the completeness of the functions and the correctness of the operation. The test of this solution is mainly divided into two parts: the first part is to test the homomorphic encryption scheme in the work, and the average execution time of various data can intuitively reflect the execution efficiency of the encryption scheme and its impact on the entire auction process; the second part is to test the execution time of the security comparison scheme of the work, and the actual comparison rate without considering the influence of network bandwidth. For the above tests, we mainly choose to test the performance of this product from two aspects: encryption time and ciphertext size. And implemented visual management, as follows Figure 7-11 As shown:

[0046] The system ultimately ensures: It addresses the shortcomings of traditional auction systems, such as online auctions and the protection of sensitive information. This solution incorporates homomorphic encryption properties, which are then used to construct a secure comparison protocol. This not only improves auction security and credibility, but also ensures bid confidentiality, fairness in the bidding process, and transparency in results, mitigating potential risks while further promoting the application and development of cryptography technology in China.

[0047] Second, as auxiliary evidence for the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0048] (1) The expected benefits and commercial value of the technical solution of the present invention after transformation are:

[0049] The technical solution of this invention can be widely applied in fields such as electronic bidding and online auctions, providing a more secure and efficient bidding mechanism. Its commercialization model can include technology licensing, system integration, customized solutions, and other methods, and is expected to generate market returns. Compared with traditional bidding methods, this solution can effectively prevent information leakage, improve bidding fairness, and possess strong market competitiveness. Furthermore, with the development of privacy computing technology and the tightening of data security regulations, this technical solution has broad application prospects in the future market and possesses high commercial and social value.

[0050] (2) The technical solution of the present invention fills the technical gap in the industry at home and abroad:

[0051] This technology fills the gap in expanding and optimizing the National Cryptography Algorithm into an encryption algorithm with homomorphic encryption properties, and successfully applies it to the field of secure voting. Through this innovation, the system achieves homomorphic computing capabilities while maintaining the security of the National Cryptography Algorithm. This allows voting data to be calculated and processed even in an encrypted state, thereby enhancing the privacy, security, and credibility of the voting process, providing important technical support for electronic voting and other privacy computing applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a structural block diagram of a privacy-secure auction system based on a national secret algorithm provided by an embodiment of the present invention.

[0053] Figure 2 This is a flow chart of a dynamic bidding truncation method provided by an embodiment of the present invention.

[0054] Figure 3 This is a system model diagram provided by an embodiment of the present invention.

[0055] Figure 4 This is a flowchart of the solution framework provided by an embodiment of the present invention.

[0056] Figure 5 This is a flow chart of a security comparison protocol provided by an embodiment of the present invention.

[0057] Figure 6 This is a flowchart of the interaction between multiple clients and a server provided by an embodiment of the present invention.

[0058] Figure 7 It is the homomorphic encryption result of SM2 provided by an embodiment of the present invention.

[0059] Figure 8 This is the security protocol comparison result provided by the embodiment of the present invention.

[0060] Figure 9 This is the auction site interface provided by an embodiment of the present invention.

[0061] Figure 10 It is the 128-bit encryption result comparison rate provided by the embodiment of the present invention.

[0062] Figure 11 It is the comparison rate of 256-bit encryption results provided by the embodiment of the present invention.

[0063] Figure 12 This is part of the encryption algorithm code provided by the embodiment of the present invention.

[0064] Figure 13 This is part of the decryption algorithm code provided by the embodiment of the present invention.

[0065] Figure 14This is part of the security comparison protocol code provided by the embodiment of the present invention.

[0066] Figure 15 This is a detailed auction product interface provided by an embodiment of the present invention.

[0067] Figure 1 In: 1. Key generation module; 2. Ciphertext comparison module; 3. Output module. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. The symbols are explained in Table 1.

[0069] Table 1 Main symbols and their meanings

[0070]

[0071] like Figure 1 As shown, an embodiment of the present invention provides a privacy-secure auction system based on a national secret algorithm, including:

[0072] Key generation module 1, ciphertext comparison module 2, output module 3;

[0073] The key generation module 1 is connected to the ciphertext comparison module 2 and the output module 3, and is used by the trusted key center to randomly select a public key and a private key, where the public key is used for encryption between the server and the user, and the private key is used for decryption by the trusted key center;

[0074] The ciphertext comparison module 2 is connected to the key generation module 1 and the output module 3, and is used for the server to send the encrypted current reserve price and identity information to the user. The user encrypts his / her own reserve price and identity information, performs ciphertext comparison, and sends the ciphertext comparison result to the server;

[0075] Output module 3 is connected to key generation module 1 and ciphertext comparison module 2. After the server receives the comparison result, it determines whether all users have participated in the comparison. If not, it updates the current reserve price and identity information and repeats the ciphertext comparison. If so, it requests the trusted key center to decrypt it and output the final reserve price and corresponding identity information.

[0076] The ciphertext comparison module provided by the embodiment of the present invention:

[0077] The SM2 algorithm used in the ciphertext comparison constructs a public key encryption with additive homomorphic properties. First, the standard SM2 scheme is part c2 and part is Where t = KDF(x2||y2,mlen), KDF: {0,1} *×mlen→{0, 1} meln , whereas in this scheme, there is no need to calculate t; secondly, the standard SM2 scheme supports message integrity verification.

[0078] The embodiment of the present invention provides a public key encryption method based on the SM2 algorithm with additive homomorphic properties:

[0079] User B randomly selects a private key Public key pk = [sk]G; the encryption process is as follows. Suppose the message m sent by user A to user B is m. User A needs to perform the following calculation steps:

[0080] 1) Generate random numbers

[0081] 2) Calculate the elliptic curve point c1 = [k]G = (x1, y1), [k]pk = (x2, y2)

[0082] 3) Calculate the elliptic curve point S = [h]pk. If S = O, report an error and exit.

[0083] 4) Calculate c2 = [m]G + [k]pk

[0084] 5) Calculate c3 = H(x2||m||y2)

[0085] 6) Output ciphertext c = (c1, c2, c3) and send it to user B via a secure channel;

[0086] The decryption process is as follows: User B receives the ciphertext c = (c1, c2, c3) sent by User A. User B then needs to perform the following calculation steps:

[0087] 1) Get c1 from the ciphertext and verify whether it satisfies the elliptic curve equation. If not, report an error and exit;

[0088] 2) Calculate the elliptic curve point S = [h]c1. If S = O, report an error and exit;

[0089] 3) Calculate the elliptic curve point [sk]c1=(x2, y2)

[0090] 4) Calculate [m]G = c2 - [sk]c1

[0091] 5) Determine whether [m]G is the identity element. If so, restore m=0; otherwise, m=1

[0092] 6) Calculate u = H(x2||m||y2) and determine whether u = c3. If so, output the plaintext m, decryption is complete, and exit; otherwise, report an error and exit.

[0093] According to the embodiment of the present invention, when there is only one user interacting with the server, the security protocol can be directly called. When there are multiple users interacting with the server, that is, assuming there are n users, the security comparison protocol is first called, and then when the current highest price and the user's identity information are obtained, it is determined whether the user is the last one. If so, the trusted key center is requested to decrypt it, and finally the highest price of the auction and the identity information of the corresponding user are output. If not, the process returns to the first step and the security comparison protocol is called again until the last user is reached.

[0094] The specific steps of the key generation module provided by the embodiment of the present invention are as follows: the trusted key center randomly selects the private key Public key pk = [sk] G; the public key is used for encryption between the server and the user, and the private key is used for decryption by the trusted key center;

[0095] The specific steps of the ciphertext comparison module are as follows: the server uses the public key to encrypt the reserve price and its own identity information and sends the encrypted result to the user; after receiving the encrypted information, the user selects a random number to hide the comparison result and encrypts the price and identity information using the public key; the user calculates the ciphertext form of the comparison result and sends it to the server via a secure channel;

[0096] The specific steps of the output module provided by the embodiment of the present invention are: after the server receives the ciphertext of the comparison result sent by the user, it determines whether all users have participated in the comparison. If not, it updates the current reserve price and identity information and repeats the ciphertext comparison. If so, it requests the trusted key center to decrypt it and output the final reserve price and corresponding identity information.

[0097] like Figure 2 As shown, a dynamic bidding truncation method provided by an embodiment of the present invention includes:

[0098] S101, using a trusted key center through a key generation module to randomly select a public key and a private key, where the public key is used for encryption between the server and the user, and the private key is used for decryption by the trusted key center;

[0099] S102, using the ciphertext comparison module, the server sends the encrypted current reserve price and identity information to the user, and the user encrypts his / her own reserve price and identity information, performs ciphertext comparison, and sends the ciphertext comparison result to the server;

[0100] S103, after receiving the comparison result from the server, the output module determines whether all users have participated in the comparison. If not, the current reserve price and identity information will be updated and the ciphertext comparison will be repeated. If so, the trusted key center will be requested to decrypt it and output the final reserve price and corresponding identity information.

[0101] Another object of the present invention is to provide a computer device, comprising 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 dynamic bidding truncation method.

[0102] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to execute the steps of the dynamic bidding truncation method.

[0103] Another object of the present invention is to provide an information data processing terminal, which is used to implement the privacy and security auction system based on the national secret algorithm.

[0104] The present invention is specifically implemented:

[0105] 1. System model, such as Figure 3

[0106] The core components of the auction system include a trusted key center, a server (i.e., the auction company), and users. The trusted key center plays a crucial role in this system. Its primary responsibilities include generating the public and private keys required for the entire system. The private key is known only to the trusted center to ensure confidentiality. Furthermore, it provides decryption query services to the server, allowing it to decrypt encrypted information when needed. Equally important, the trusted key center is responsible for publishing the final auction price and associated identity information to ensure transparency and traceability of the auction process.

[0107] The server plays multiple roles in the auction system. First, it provides the initial price, serving as the starting point for the auction. Second, the server is responsible for securely storing the price obtained after each bid, along with its corresponding identity information, in encrypted form to protect bidders' privacy and confidentiality. This encrypted storage mechanism is designed to prevent price information from being leaked or tampered with. The server acts as an information hub, providing a secure platform for bidders to compare prices and transmit data.

[0108] Bidders are one of the main entities in the auction system. Their primary task is to compare their bids with the server's price in encrypted form and send the encrypted comparison result to the server. This mechanism allows users to participate in the auction process without revealing their bids. In this way, auction users can maintain the confidentiality of their bidding strategies while ensuring the security and reliability of the auction system.

[0109] By running this solution, the server always stores the identity and ciphertext of the user with the highest current bid. After the auction, the key center's private key is used to recover the highest price and its user's identity. The collaboration and interaction between the trusted key center, the server, and the bidders form a comprehensive auction mechanism that aims to address the information protection and credibility issues of traditional auction systems.

[0110] 2. Programme framework; Figure 4

[0111] This section introduces the framework of the scheme. After the system is successfully established, the trusted key center generates public and private keys. The encryption and decryption algorithm uses a public key encryption scheme based on the SM2 algorithm, repeatedly calling the security comparison protocol until the current highest price and the user's identity information are output.

[0112] 3. Encryption algorithm;

[0113] This section focuses on the security comparison protocol between users and servers in the scheme framework and the modified SM2 algorithm. The following is a brief description of the public key encryption scheme with additive homomorphic properties based on the SM2 algorithm. It was proposed by Tang Fei, Ling Guowei and Shan Jinyong in 2022. It only makes adjustments to the encryption and decryption algorithms of the standard SM2 scheme. First, the c2 part of the standard SM2 scheme is Where t = KDF(x²||y²,mlen), KDF: {0, 1} * ×mlen→{0,1} mlen , but in this scheme, there is no need to calculate t; secondly, the standard SM2 scheme supports message integrity verification

[14] The modified SM2 homomorphic encryption scheme offers better ciphertext verification than conventional additive homomorphic schemes. However, it's worth noting that the c3 portion is a digest generated by a cryptographic hash function and lacks additive homomorphism. However, this is acceptable from a practical perspective.

[0114] 1) System establishment

[0115] Let A and B be the encryption user and decryption user respectively. They set the same public parameter parameter in advance, q is a large prime number, and E is defined in the finite field F. p The elliptic curve on G is the q-order base point of the elliptic curve, and the bit length mlen of the plaintext space M is set to 32 bits. [k]G represents the k-fold point of the elliptic curve base point G, and the cryptographic hash function H: {0, 1}→Z q , x||y represents the concatenation of byte strings or bit strings x and y, Represents the exclusive OR operation between bit strings.

[0116] 2) Key Generation

[0117] User B randomly selects a private key Public key pk = [sk] G.

[0118] 3) Encryption algorithm process

[0119] Assume that the message sent by user A to user B is m. User A needs to perform the following calculation steps:

[0120] a) Generate random numbers

[0121] b) Calculate the elliptic curve point c1 = [k]G = (x1, y1), [k]pk = (x2, y2)

[0122] c) Calculate the elliptic curve point S = [h]pk. If S = O, report an error and exit.

[0123] d) Calculate c2 = [m]G + [k]pk

[0124] e) Calculate c3 = H(x2||m||y2)

[0125] f) Output the ciphertext c = (c1, c2, c3) and send it to user B through a secure channel.

[0126] 4) Decryption algorithm process

[0127] When user B receives the ciphertext c = (c1, c2, c3) from user A, user B needs to perform the following calculation steps:

[0128] a) Get c1 from the ciphertext and verify whether it satisfies the elliptic curve equation. If not, report an error and exit;

[0129] b) Calculate the elliptic curve point S = [h]c1. If S = O, report an error and exit;

[0130] c) Calculate the elliptic curve point [sk]c1=(x2,y2)

[0131] d) Calculate [m]G = c2 - [sk]c1

[0132] e) Determine whether [m]G is the identity element. If so, restore m=0; otherwise, m=1

[0133] f) Calculate u = H(x2||m||y2) and determine whether u = c3. If so, output the plaintext m, decryption is complete, and exit; otherwise, report an error and exit.

[0134] 4. Security comparison protocol; e.g. Figure 5

[0135] This section gives the specific protocol process of the auction system in realizing the interaction between users, servers and trusted key centers.

[0136] 1) System establishment

[0137] The trusted key center and the user set the same public parameters in advance, where p is a large prime number and E is defined in the finite field F. p The elliptic curve on G is the q-order base point of the elliptic curve, and the bit length mlen of the plaintext space M is set to 32 bits. [k]G represents the k-fold point of the elliptic curve base point G, and the cryptographic hash function H: {0, 1}→Z q , x||y represents the concatenation of byte strings or bit strings x and y, Represents the exclusive OR operation between bit strings.

[0138] 2) Key Generation

[0139] The trusted key center randomly selects the private key Public key pk = [sk] G.

[0140] 3) The server encrypts the information and sends it to the user

[0141] The server uses pk to compare the reserve price x and its own identity information ID x Encryption is performed to obtain [x]=([x1],…[x t ]) and [ID x ] and send it to the user.

[0142] 4) After receiving the encrypted information, the user uses the comparison protocol to obtain C

[0143] a) The user randomly selects b1∈{0,1} and calculates s=1-2·b1;

[0144] b) Use pk to bid and identity information ID y Encrypted separately

[0145] [y]=([y1],…[y t ]),

[0146] [ID y ];

[0147] 5) For i∈{1,…,t}, choose calculate a) Get C=([c1],…,[c t ]) and combine it with [y], [b1x i ]、[b1y i ]、[IDy ]、[b1ID x ]、[b1ID y ]Together

[0148] Sent to the server via a secure channel.

[0149] 6) After receiving C, the server needs to decrypt it and send it to the trusted key center

[0150] 7) The trusted key center obtains b2 through decryption and sends it to the server through a secure channel

[0151] For i∈{1,…,t}, the trusted key center decrypts to get c i ;

[0152] If and only if c i When all are not 0, b2=0; otherwise b2=1.

[0153] 8) Server calculates ciphertext

[0154] First, for When b2=0, When b2=1, Secondly, for When b2=0, When b2=1, And for Similar to the above process.

[0155] 9) The server obtains the current highest price and the user's identity information

[0156] like Figure 6 When there is one user interacting with the server, the security protocol can be directly called; when there are multiple users interacting with the server, that is, assuming there are n users, the security comparison protocol is called first, and then when the current highest price and the user's identity information are obtained, it is determined whether it is the last user. If so, the trusted key center is requested to decrypt it, and finally the highest price of the auction and the corresponding user's identity information are output; if not, the first step is returned to call the security comparison protocol again, until the last user.

[0157] 1. Specific application fields or related products of the present invention.

[0158] To verify the feasibility, innovation, and technical value of this invention's technical solution, we designed and implemented a secure auction system based on the nationally recognized SM2 algorithm, and conducted detailed testing and analysis. This system leverages the homomorphic encryption properties of the SM2 algorithm to ensure secure comparison of bid prices even when they are encrypted. Furthermore, it incorporates a multi-party collaborative mechanism to ensure auction fairness, security, and privacy protection.

[0159] (1) System architecture and implementation. This system consists of the following core modules:

[0160] Bidding client: responsible for SM2 encryption of the bidding price and submitting the ciphertext to the auction server.

[0161] Auction server: stores the ciphertext of the current highest bid and the encrypted identity information of the corresponding bidder, and compares bids without decryption.

[0162] Trusted Key Center: After the auction ends, it assists in decrypting the highest bid price and its corresponding user identity to ensure the transparency and credibility of the auction results.

[0163] Visual management platform: used to monitor the auction progress in real time and provide bidding data analysis functions to facilitate auction company management.

[0164] (2) Functional testing

[0165] To further verify the performance and safety of the present invention, we designed two main test parts:

[0166] Part 1: Homomorphic Encryption Scheme Testing

[0167] By encrypting auction price data of varying sizes and measuring encryption execution time, we evaluated the solution's applicability in a highly concurrent environment. We also calculated the ciphertext storage overhead for different encrypted data sizes and analyzed its impact on server storage resources.

[0168] Part II: Security Comparison Program Testing

[0169] Without considering the impact of network bandwidth, we tested the dense comparison rate under different bidding data volumes to ensure that this solution can support large-scale auction scenarios. We also evaluated the system response time under different user numbers and bidding frequencies to ensure the real-time and efficient auction process.

[0170] (3) Real case analysis

[0171] To further validate the practical application value of this solution, we selected an online bidding platform as a case study, deployed our secure auction system, and conducted bidding tests simulating a real-world auction environment. The test results demonstrate that this system accurately and efficiently calculates the highest bid while ensuring the privacy of bidding data, effectively preventing bidders from cheating by submitting prices at the auction closing moment. Furthermore, experimental data demonstrates that compared to traditional plaintext bidding systems, this solution significantly improves security, privacy protection, and fairness, meets the compliance requirements of national secret algorithms, and is suitable for various types of domestic electronic bidding and auction services.

[0172] in conclusion:

[0173] Through experiments and analysis in this application example, the proposed secure auction scheme based on the homomorphic encryption SM2 algorithm demonstrates its effectiveness in terms of security, privacy protection, and bidding fairness. This scheme not only addresses the information leakage and unfairness issues in traditional auction systems but also demonstrates excellent commercial value in terms of performance, compliance, and usability, offering broad application prospects.

[0174] 2. Relevant evidence of the technical effects obtained by the embodiments of the present invention.

[0175] This patent implementation is based on a personal computer equipped with an Intel(R) Core(TM) i5-9300H CPU @ 2.40GHz and 16GB of RAM, using the Python-based homomorphic encryption library Tenseal and the editor PyCharm. Under this configuration, system testing, functional testing, and performance testing were performed. The implementation principles will be analyzed from the following algorithmic levels: the additively homomorphic SM2 encryption algorithm, the decryption algorithm, and the security comparison algorithm.

[0176] 1. National SM2 encryption algorithm

[0177] The National Security Agency's SM2 encryption algorithm is based on an elliptic curve cryptography (ECC) algorithm. Firstly, ECC offers high security given its high key length and is more difficult to crack than the RSA algorithm. Secondly, the algorithm uses a hash function, ensuring that any slight change in the input data results in a significant change in the output hash value. Furthermore, the parameter k is randomly generated, further enhancing the algorithm's security.

[0178] Therefore, from a theoretical perspective, if an attacker wants to crack the algorithm, they must use brute force or cryptographic vulnerabilities to try to crack it. In addition, this solution involves the calculation of elliptic curve encryption and hash functions, which have complex encryption algorithms and data structures and therefore have high computational complexity. Figure 12 .

[0179] Figure 13 This is part of the decryption algorithm code provided by the embodiment of the present invention.

[0180] Figure 14 This is part of the security comparison protocol code provided by the embodiment of the present invention.

[0181] Figure 15 This is a detailed auction product interface provided by an embodiment of the present invention.

[0182] Decryption algorithm

[0183] In this solution, the private key is generated and stored by a secure third party, with extremely strict security measures in place to ensure the key is securely used in the decryption algorithm and cannot be leaked or stolen. Furthermore, the algorithm involves the principles of elliptic curve cryptography, point subtraction, and ECC tables. These calculations require extensive mathematical and cryptographic knowledge, making the decryption algorithm relatively complex and thus ensuring its security.

[0184] Security comparison algorithm

[0185] Based on additive homomorphism, the algorithm uses bit-by-bit encryption to compare sizes. Users can control the adjustment factor s by selecting a random value b1, which increases its randomness and flexibility.

[0186] Run Results

[0187] This section will introduce the results of this work, including the three modules of data encryption and decryption and security protocol comparison. The plaintext remains consistent before and after the encryption and decryption process. The security protocol comparison results are as follows: Figure 7 shown.

[0188] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware portion can be implemented using dedicated logic; the software portion can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. Those skilled in the art will appreciate that the above-mentioned devices and methods can be implemented using computer-executable instructions and / or contained in processor control code, for example, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, or can be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0189] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A privacy-safe auction system based on a national secret algorithm, characterized by: include: Key generation module, ciphertext comparison module, output module; The key generation module is connected to the ciphertext comparison module and the output module, and is used by the trusted key center to randomly select public keys and private keys. The public key is used for encryption between the server and the user, and the private key is used for decryption by the trusted key center. The ciphertext comparison module is connected to the key generation module and the output module. The server sends the encrypted current reserve price and identity information to the user. The user encrypts his / her own reserve price and identity information, performs ciphertext comparison, and sends the ciphertext comparison result to the server. The output module is connected to the key generation module and the ciphertext comparison module. After the server receives the comparison result, it determines whether all users have participated in the comparison. If not, it will update the current reserve price and identity information and repeat the ciphertext comparison. If so, it will request the trusted key center to decrypt it and output the final reserve price and corresponding identity information.

2. The privacy-safe auction system based on the national secret algorithm as claimed in claim 1, characterized in that: The ciphertext comparison module: The SM2 algorithm used in the ciphertext comparison constructs a public key encryption with additive homomorphic properties. First, the standard SM2 scheme is part c2 and part is Where t = KDF(x2||y2,mlen), KDF: {0,1} * ×mlen→{0, 1} mlen , whereas in this scheme, there is no need to calculate t; secondly, the standard SM2 scheme supports message integrity verification.

3. The privacy-safe auction system based on the national secret algorithm as claimed in claim 2, characterized in that: The public key encryption with additive homomorphic properties constructed based on the SM2 algorithm is: User B randomly selects a private key Public key pk = [sk]G; the encryption process is as follows. Suppose the message m sent by user A to user B is m. User A needs to perform the following calculation steps: 1) Generate random numbers 2) Calculate the elliptic curve point c1 = [k]G = (x1, y1), [k]pk = (x2, y2) 3) Calculate the elliptic curve point S = [h]pk. If S = O, report an error and exit. 4) Calculate c2 = [m]G + [k]pk 5) Calculate c3 = H(x2||m||y2) 6) Output ciphertext c = (c1, c2, c3) and send it to user B via a secure channel; The decryption process is as follows: User B receives the ciphertext c = (c1, c2, c3) sent by User A. User B then needs to perform the following calculation steps: 1) Get c1 from the ciphertext and verify whether it satisfies the elliptic curve equation. If not, report an error and exit; 2) Calculate the elliptic curve point S = [h]c1. If S = O, report an error and exit; 3) Calculate the elliptic curve point [sk]c1=(x2, y2) 4) Calculate [m]G = c2 - [sk]c1 5) Determine whether [m]G is the identity element. If so, restore m=0; otherwise, m=1 6) Calculate u = H(x2‖m‖y2) and determine whether u = c3. If so, output the plaintext m, decryption is complete, and exit; otherwise, report an error and exit.

4. The privacy-safe auction system based on the national secret algorithm as claimed in claim 2, characterized in that: When there is a single user interacting with the server, the security protocol is directly called. When there are multiple users interacting with the server, that is, assuming there are n users, the security comparison protocol is called first. Then, when the current highest price and the user's identity information are obtained, it is determined whether it is the last user. If so, the trusted key center is requested to decrypt it, and finally the highest price of the auction and the corresponding user's identity information are output. If not, the process returns to the first step and the security comparison protocol is called again until the last user is reached.

5. The privacy-safe auction system based on the national secret algorithm as claimed in claim 1, characterized in that: The specific steps of the key generation module are: the trusted key center randomly selects the private key Public key pk = [sk] G; the public key is used for encryption between the server and the user, and the private key is used for decryption by the trusted key center; The specific steps of the ciphertext comparison module are as follows: the server uses the public key to encrypt the reserve price and its own identity information respectively and sends the encrypted result to the user; after receiving the encrypted information, the user selects a random number to hide the comparison result and uses the public key to encrypt the price and identity information respectively; the user calculates the ciphertext form of the comparison result and sends it to the server through a secure channel.

6. The privacy-safe auction system based on the national secret algorithm as claimed in claim 1, characterized in that: The specific steps of the output module are as follows: after the server receives the ciphertext of the comparison result sent by the user, it determines whether all users have participated in the comparison. If not, it updates the current reserve price and identity information and repeats the ciphertext comparison. If so, it requests the trusted key center to decrypt it and output the final reserve price and corresponding identity information.

7. A method for implementing a dynamic bidding truncation system for a privacy-secure auction system based on a national secret algorithm as described in any one of claims 1 to 6, characterized in that: The dynamic bidding truncation method includes: Step 1: The key generation module uses the trusted key center to randomly select a public key and a private key. The public key is used for encryption between the server and the user, and the private key is used for decryption by the trusted key center. Step 2: The encrypted current reserve price and identity information are sent to the user by the server through the ciphertext comparison module. The user encrypts his / her own reserve price and identity information, performs ciphertext comparison, and sends the ciphertext comparison result to the server. Step 3: After receiving the comparison result from the server, the output module determines whether all users have participated in the comparison. If not, the current reserve price and identity information will be updated and the ciphertext comparison will be repeated. If so, the trusted key center will be requested to decrypt it and output the final reserve price and corresponding identity information.

8. A computer device, characterized in that: The computer device includes 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 dynamic bidding truncation method according to claim 7.

9. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor is caused to perform the steps of the dynamic bidding truncation method according to claim 7.

10. An information data processing terminal, characterized in that: The information data processing terminal is used to implement the privacy and security auction system based on the national secret algorithm as described in any one of claims 1-6.

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