A process method of a user privacy preserving continuous authentication protocol

Abstract

This invention discloses a continuous authentication protocol for maintaining user privacy. The protocol process includes four stages: system initialization, credential registration, legitimacy check, and consistency check. First, the system generates public parameters, and the credential issuer generates a public-private key pair and an update key. The user and the credential issuer generate credentials using blind signatures. Then, the user generates and submits a randomized credential to the network service provider (ISP). The ISP verifies the legitimacy of the user's credential based on the credential issuer's public key and its specific service access conditions. Finally, during continuous authentication, consistency proof generation and verification enable the ISP to perform identity consistency checks based on user autonomy. This invention places greater emphasis on protecting user data privacy at the ISP's location.

Description

Technical Field

[0001] This invention belongs to the technical field of privacy and security protection, and specifically relates to a process method for a continuous authentication protocol for maintaining user privacy. Background Technology

[0002] In recent years, with the rapid development of information technology and the widespread application of online services, Continuous Authentication (CA) has become increasingly important. Traditional one-time authentication can no longer meet modern security needs due to frequent cyberattacks and identity theft. Continuous authentication ensures the credibility of a user's identity throughout the entire session by monitoring user behavior and environment in real time, effectively preventing illegal fraud and unauthorized access. With the development of IoT and AI technologies, the application scenarios of CA are constantly expanding, making security protection more intelligent and flexible. However, users need to provide a large amount of personal data during the authentication process, but the lack of control over the use of this data may lead to privacy leaks. In addition, data is easily eavesdropped or intercepted during transmission, further increasing privacy risks.

[0003] Currently, existing solutions for protecting user privacy in continuous identity authentication (CA) primarily focus on designing key exchange protocols between users and network service providers (ISPs). Secure key exchange establishes a secure communication channel between users and ISPs, thus preventing the leakage of user privacy data during transmission. However, in existing solutions, user privacy data remains transparent to the ISP. These solutions do not consider that the ISP itself may be untrustworthy or vulnerable. Untrustworthy ISPs may use collected user data for privacy mining or leak user privacy data to third parties without user permission; while vulnerable ISPs may have management deficiencies that allow attackers to obtain user data, ultimately resulting in losses borne by the user.

[0004] To address these issues, the Anonymous Credential System (ACS) has demonstrated significant potential in identity authentication for protecting user privacy in recent years. ACS enables users to exercise identity sovereignty, allowing them to prove their legitimacy to network service providers without revealing personal data or their true identity. This mechanism not only enhances user privacy but also grants users the right to selectively disclose their data, allowing them to decide when and how to share personal information based on their specific needs. Compared to traditional public key infrastructure certificate systems, ACS places greater emphasis on protecting user privacy while maintaining the effectiveness of identity verification. By using anonymous credentials, users can avoid exposing excessive personal information during identity authentication, thereby reducing the risk of identity theft or misuse. Currently, ACS is widely used in blockchain identity management systems, which leverage the decentralized nature of blockchain to further enhance the security and transparency of identity management.

[0005] However, relying solely on these ACS (Authentication, Authorization, and Certification) protocols is insufficient to achieve continuous authentication protocols that maintain user privacy. This is because the goals of ACS and CA (Certificate Authority) conflict: ACS aims to protect user identity privacy, prevent unauthorized access or leakage of personal information, and require anonymity between requests; while CA aims to enable service providers to continuously verify user identities, ensuring the system can verify the legitimacy of user identities throughout the session. In other words, CA needs to check user consistency to establish linkability between user requests, thereby ensuring that requests originate from the same user. Therefore, there is a conflict between the anonymity in ACS and the linkability in CA, making it difficult to directly apply ACS to CA, limiting the large-scale deployment of continuous authentication protocols that maintain user privacy, and seriously jeopardizing user privacy. Summary of the Invention

[0006] This invention addresses the problem of user privacy leakage to network service providers in existing continuous authentication protocols. It constructs a process method for continuous authentication protocols based on subset proofs and anonymous consistency credentials to maintain user privacy. The protocol process includes four stages: system initialization, credential registration, legitimacy check, and consistency check. First, the system generates public parameters, and the credential issuer generates a public-private key pair and an update key. The user and the credential issuer generate credentials using blind signatures. Then, the user generates and submits a randomized credential to the network service provider, which verifies the legitimacy of the user's credential based on the credential issuer's public key and its specific service access condition set. Finally, during continuous authentication, consistency proof generation and verification enable the network service provider to check the consistency of the user's identity, based on the user's autonomy. This invention's protocol, through subset proofs, allows users to disclose only the minimum necessary identity data, thus achieving selective disclosure and proving the legitimacy of their identity. Furthermore, to support fine-grained continuous identity authentication, the consistency proof of this invention allows anonymous users to prove that different credentials are bound to the same set of user attributes. At the same time, users have the right to decide whether to send the consistency proof, which places greater emphasis on the privacy protection of user data at the network service provider.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a process method for a continuous authentication protocol for maintaining user privacy, wherein the protocol process includes at least the following steps:

[0008] S1, System Initialization Phase: The system generates public parameters for subsequent protocols, and the credential issuer generates public-private key pairs and update keys;

[0009] S2, Certificate Registration Phase: Users and certificate issuers generate certificates using blind signatures;

[0010] S3, Legality Check Phase: The user generates and submits the randomized credentials obtained in step S2 to the network service provider. The network service provider verifies the legality of the user's credentials based on the public key of the credential issuer and its specific service access condition set.

[0011] S4, Consistency Check Phase: During continuous authentication, consistency proof generation and consistency proof verification enable network service providers to check the consistency of user identities based on user autonomy.

[0012] As an improvement of the present invention, step S2, the credential registration stage, specifically includes the following steps:

[0013] S21, Encrypted Upload of User Identity Attribute Set: The user sequentially encodes and encrypts the user identity attributes through polynomial encoding, polynomial commitment, and commitment encryption before uploading.

[0014] S22, Blind Signature Generation: After receiving the ciphertext from the user in step S21, the credential issuer uses its private key to sign the encrypted data and sends the signature result back to the user.

[0015] S23, User identity credential generation: The user uses their own decryption key and the credential issuer's public key to decrypt the signature result, calculate and obtain the user identity credential.

[0016] As an improvement to the present invention, after step S21 sequentially using polynomial encoding, polynomial commitment, and commitment encryption, the encrypted ciphertext is:

[0017]

[0018] in, A randomly generated encryption key for the user. For the random number field, For the agreed group generator, To encrypt ciphertext;

[0019] Blind signature generation in step S22:

[0020]

[0021] in, For the generated blind signature, The private key of the certificate issuer;

[0022] The user identity credential obtained in step S23 is: ;

[0023] in, A multinomial commitment to hold a set of identity attributes for a user. This serves as necessary evidence for users to prove their legitimacy to network service providers.

[0024] As another improvement of the present invention, the legality check stage of step S3 specifically includes the following steps:

[0025] S31, Credential Randomization: The user randomizes the credential using a locally generated random number and an update key provided by the credential issuer;

[0026] S32, Credential Validation: The network service provider uses the credentials received from the user and the public key provided by the credential issuer to verify the validity of the user's identity; the network service provider uses the local set of service access requirements and the credentials provided by the user to verify that the user meets the requirements for accessing the target service through subset proof.

[0027] As another improvement of the present invention, in the randomized certificate of step S31, the randomized polynomial commitment Randomized signature Randomized evidence :

[0028]

[0029]

[0030]

[0031] ;

[0032] As another improvement of the present invention, in step S32, the network service provider uses the credentials received from the user. and the public key provided by the certificate issuer Verify the validity of user identity:

[0033]

[0034] Network service providers utilize local service access request sets And the credentials provided by the user The subset proof verifies that it meets the requirements for accessing the target service:

[0035] .

[0036] As another improvement of the present invention, the consistency check stage of step S4 specifically includes the following steps:

[0037] S41, Consistency Proof Generation: The user generates an anonymous consistency proof using public parameters, two randomized credentials, a random number generated locally by the user, and a challenge from the network service provider, and sends it to the network service provider.

[0038] S42, Consistency Proof Verification: After receiving an anonymous consistency proof from the user, the network service provider uses the two proofs, the challenge generated by the network service provider, and the statement generated by the user to verify the validity of the proof.

[0039] As a further improvement of the present invention, step S41, generating the consistency proof, specifically includes the following steps:

[0040] S411: User generates random number ;

[0041] S412: Generate Declaration The statement will be sent to the network service provider:

[0042] ;

[0043] S413: The network service provider receives a statement from the user. Then, a random challenge is generated. and will challenge Send to the user;

[0044] S414: The user receives the challenge in step S413. and the random number generated in step S411 Generate a consistency proof And send it to the network service provider, where:

[0045]

[0046] in, For user identity attribute set Polynomial encoding The coefficients of each, Generate polynomial commitments for users The random number selected at that time;

[0047]

[0048] .

[0049] As a further improvement of the present invention, the consistency verification step S42 specifically includes:

[0050]

[0051] .

[0052] Compared with existing technologies, the technical advantages and effects of this invention are as follows: This invention provides a process method for a continuous authentication protocol that maintains user privacy. Compared with existing methods, this invention uses subset proofs to allow users to disclose only the minimum necessary identity data to prove their identity legitimacy, achieving selective disclosure of identity authentication. Simultaneously, to support fine-grained continuous identity authentication, this invention constructs a new consistency proof, allowing anonymous users to prove that different credentials are bound to the same set of user attributes, where the user has the right to decide whether to send the consistency proof. Compared to existing methods that only emphasize the confidentiality protection of user data transmitted in the channel, this invention places greater emphasis on maintaining the privacy of user data for the network service provider. Attached Figure Description

[0053] Figure 1 This is a flowchart of a continuous authentication protocol for maintaining user privacy, as described in this invention. Detailed Implementation

[0054] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0055] Example 1

[0056] This invention discloses a process method for a continuous authentication protocol that maintains user privacy, involving three entities: a credential issuer, a user, and a network service provider. The communication process between these entities is divided into four stages: system initialization, credential registration, legitimacy check, and consistency check. In the initialization stage, the system needs to generate publicly available parameters and the key used by the credential issuer to facilitate the execution of subsequent processes. In the credential registration stage, the user and the credential issuer generate a user identity credential based on the user's set of user identity attributes through blind signature. In the legitimacy check stage, the user and the network service provider verify the legitimacy of the user's identity through credential randomization and credential legitimacy verification, ensuring user privacy and anonymity. In the consistency check stage, the network service provider verifies the consistency of the user's identity through consistency proof generation and verification, based on the user's autonomy.

[0057] A continuous authentication protocol for maintaining user privacy, such as Figure 1 As shown, the specific steps included in its protocol flow are as follows:

[0058] Step S1: System initialization phase;

[0059] During the system initialization phase, it is necessary to generate the system's public parameters, including the bilinear mapping group and the reference point system on the group; it is also necessary to generate the public and private key pair of the credential issuer for subsequent signature generation and verification, as well as the credential issuer's update key for user credential randomization.

[0060] Assume that the length of the user's identity attribute set is... First, a bilinear mapping group needs to be selected. Reference point system on the group ,in For random numbers, and ,in , This should be a random number. Additionally, a public / private key pair for the credential issuer needs to be generated. , This is used for subsequent signature generation and verification, as well as for the credential issuer to update the key. It is used for randomizing user credentials.

[0061] Step S2, Credential Registration Stage: Users and credential issuers generate credentials using blind signatures without exposing the user's identity attribute set.

[0062] S21: Encrypted Upload of User Identity Attribute Set. Users need to encode their identity attributes into a multinomial commitment. To avoid potential privacy leaks and identity theft risks due to the transparency of the user identity attribute set to the credential issuer, users need to encrypt the multinomial commitment using their private encryption key when registering identity credentials and then upload the ciphertext to the credential issuer.

[0063] Assume the user's identity attribute set is Then its encoded polynomial and polynomial commitment are:

[0064]

[0065]

[0066] in For each element in the attribute set, It is a random number.

[0067] To avoid potential privacy breaches and identity theft risks arising from the transparency of user identity attributes to the credential issuer, users are required to encrypt multinomial commitments using their private encryption key when registering identity credentials. The encrypted ciphertext is as follows:

[0068]

[0069] in A randomly generated encryption key is provided for the user. The user then uploads the encrypted data to the credential issuer.

[0070] S22: Blind signature generation. After receiving the ciphertext from the user, the certificate issuer uses its private key to sign the encrypted data and sends the signature result back to the user.

[0071] The certificate issuer received encrypted messages from the user. Then, using the private key of the credential issuer... The encrypted data is signed, and the signature result is sent back to the user. The signature is generated as follows:

[0072]

[0073] S23: User identity credential generation. The user uses their own decryption key and the credential issuer's public key to decrypt the signature result, calculate and obtain the user identity credential.

[0074] Users use their own decryption keys and the public key of the credential issuer Decrypt the signature result and calculate and obtain the signature of the original polynomial commitment:

[0075]

[0076] Suppose that the set of specific service access conditions for a certain service on a network service provider is as follows: Users can generate specific identity credentials for this service to prove their identity. This means the user has met all the access conditions. First, consider S except for... The elements in the code are multinomial encoded to generate evidence. :

[0077]

[0078]

[0079] Then, organize and obtain the user's identity credentials:

[0080]

[0081] Step S3, Legality Check Phase: The user generates and submits a randomized credential to the network service provider, which then verifies the legality of the user's credential based on the credential issuer's public key and its specific service access condition set.

[0082] S31: Voucher Randomization

[0083] To prevent users from repeatedly using the same credentials during multiple authentication attempts, which could lead to identity leaks, users need to randomize their credentials before each authentication process. Users utilize an update key provided by the credential issuer. and random numbers generated locally by the user and public parameters Randomize the credentials. The randomized credentials include randomized multinomial commitments. Randomized signature Randomized evidence .

[0084]

[0085]

[0086]

[0087]

[0088] The randomized credentials are then sent to the network service provider.

[0089] S32: Verification of credential validity

[0090] Before providing network services to users, network service providers need to verify the validity of the user's identity and whether they meet specific service access conditions. The network service provider verifies the validity of the user's identity using the credentials received from the user and the public key provided by the credential issuer. Furthermore, the network service provider also needs to use a local set of service access requirements and the user-provided credentials to verify that the user meets the requirements for accessing the target service through subset proof. Only when the user-provided credentials simultaneously satisfy both of the above conditions can the legitimacy verification be passed.

[0091] Network service providers use the credentials they receive from users and the public key provided by the certificate issuer Verify the validity of user identity:

[0092]

[0093] In addition, network service providers also need to utilize local service access request sets. And the credentials provided by the user The subset proof verifies that it meets the requirements for accessing the target service:

[0094]

[0095] Only when the credentials provided by the user meet both of the above conditions can the validity verification be passed.

[0096] Step S4, Consistency Check Phase: During continuous authentication, consistency proof generation and consistency proof verification enable network service providers to check the consistency of user identities based on user autonomy.

[0097] S41: Consistency Proof Generation

[0098] In continuous authentication protocols, network service providers need to verify the consistency of a user's identity in real time. Therefore, users need to prove that the two randomized credentials used in the previous and current authentication processes are from the same source. Assume the user's two credentials are as follows: .in, The polynomial commitments contained therein are: ; The polynomial commitments contained therein are: . These are different random numbers used in the two randomization processes. Users need to ensure that these are not exposed... Proof under the premise Originating from the same .

[0099] First, the user needs to generate random numbers. ;

[0100] Then, generate the declaration. The statement will then be sent to the network service provider, as shown below:

[0101]

[0102] Next, the network service provider receives a statement from the user. Then, a random challenge is generated. and will challenge Send to the user;

[0103] Finally, the user based on the challenge received. and previously generated random numbers Generate a consistency proof And send it to the network service provider, where:

[0104]

[0105] S42: Conformity Proof Verification

[0106] The network service provider receives anonymous consistency proof from the user. Then, using the vouchers from both the beginning and end. This poses challenges for network service providers. And statements generated by users To verify the validity of the proof, the verification method is as follows:

[0107]

[0108]

[0109] If the verification passes, it means that both credentials came from the same user.

[0110] In summary, this invention utilizes subset proofs to allow users to disclose only the minimum necessary identity data to prove their identity legitimacy, thus maintaining the privacy of user data for network service providers and anonymizing user identity for network service providers. Addressing the issue that continuous authentication protocols require checks on user identity consistency and cannot be directly integrated with anonymous credential systems, this invention provides a consistency proof that allows anonymous users to prove different credentials are bound to the same set of user attributes, enabling network service providers to check user identity consistency while maintaining user privacy.

[0111] It should be noted that the above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A process method for a continuous authentication protocol that maintains user privacy, characterized in that, The protocol process includes the following steps: S1, System Initialization Phase: The system generates public parameters for subsequent protocols, and the credential issuer generates public-private key pairs and update keys; S2, Certificate Registration Phase: Users and certificate issuers generate certificates using blind signatures; S3, Legality Check Phase: The user generates and submits the randomized credentials obtained in step S2 to the network service provider. The network service provider verifies the legality of the user's credentials based on the public key of the credential issuer and its specific service access condition set. S31, Credential Randomization: The user randomizes the credential using a locally generated random number and an updated key provided by the credential issuer; in the randomized credential, the randomized multinomial commitment... Randomized signature Randomized evidence : ； ； ； ； in Random numbers generated for the user; S32, Credential Validation: The network service provider uses the credentials received from the user and the public key provided by the credential issuer to verify the validity of the user's identity; the network service provider uses the local service access requirement set and the credentials provided by the user to verify that the user meets the requirements for accessing the target service through subset proof; the network service provider uses the credentials received from the user... and the public key provided by the certificate issuer Verify the validity of user identity: ； in, For the agreed bilinear mapping; Network service providers utilize local service access request sets And the credentials provided by the user The subset proof verifies that it meets the requirements for accessing the target service: ； S4, Consistency Check Phase: During continuous authentication, consistency proof generation and consistency proof verification enable network service providers to check the consistency of user identities based on user autonomy.

2. The process method for a continuous authentication protocol for maintaining user privacy as described in claim 1, characterized in that: The S2 credential registration stage specifically includes the following steps: S21, Encrypted Upload of User Identity Attribute Set: The user sequentially encodes and encrypts the user identity attributes through polynomial encoding, polynomial commitment, and commitment encryption before uploading. S22, Blind Signature Generation: After receiving the ciphertext from the user in step S21, the credential issuer uses its private key to sign the encrypted data and sends the signature result back to the user. S23, User identity credential generation: The user uses their own decryption key and the credential issuer's public key to decrypt the signature result, calculate and obtain the user identity credential.

3. The process method for a continuous authentication protocol for maintaining user privacy as described in claim 2, characterized in that: After step S21 sequentially uses polynomial encoding, polynomial commitment, and commitment encryption, the encrypted ciphertext is: ； in, A randomly generated encryption key for the user. For the random number field, For the agreed group generator, To encrypt ciphertext; Blind signature generation in step S22: ； in, For the generated blind signature, The private key of the certificate issuer; The user identity credential obtained in step S23 is: ; in, A multinomial commitment to hold a set of identity attributes for a user. This serves as necessary evidence for users to prove their legitimacy to network service providers. This is the signature of the original polynomial commitment.

4. The process method for a continuous authentication protocol for maintaining user privacy according to claim 1, characterized in that: The consistency check phase, step S4, specifically includes the following steps: S41, Consistency Proof Generation: The user generates an anonymous consistency proof using public parameters, two randomized credentials, a random number generated locally by the user, and a challenge from the network service provider, and sends it to the network service provider. S42, Consistency Proof Verification: After receiving an anonymous consistency proof from the user, the network service provider uses the two proofs, the challenge generated by the network service provider, and the statement generated by the user to verify the validity of the proof.

5. The process method for a continuous authentication protocol for maintaining user privacy according to claim 4, characterized in that: The consistency proof generation step S41 specifically includes the following steps: S411: User generates random number ; S412: Generate Declaration The statement will be sent to the network service provider: ； in and Common system parameters generated during the initialization phase; S413: The network service provider receives a statement from the user. Then, a random challenge is generated. and will challenge Send to the user; S414: The user receives the challenge in step S413. and the random number generated in step S411 Generate a consistency proof And send it to the network service provider, where: ； in, For user identity attribute set Polynomial encoding The coefficients of each, Generate polynomial commitments for users The random number selected at that time; ； 。 6. The process method for a continuous authentication protocol for maintaining user privacy according to claim 5, characterized in that: The specific steps of the consistency proof verification in step S42 are as follows: ； 。

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