Cloud data security sharing method with revocable anonymity

Abstract

The invention relates to the technical field of data processing, in particular to a cloud data security sharing method with revocable anonymity, which comprises the following steps: initializing an SM9 ring signature system with revocable anonymity, outputting system public parameters, and meanwhile, initializing an identity set list and a user list with revocable anonymity; a signer randomly selects an identity set of n-1 users, executes an SM9 ring signature algorithm capable of revoking anonymity, and outputs a signature sigma; the signer executes signature sigma encryption operation on the authorizer set to obtain a ciphertext; an authorizer receives the ciphertext and can perform related operation on the data, if a problem exists in the data operation process, a third party is requested to perform identity tracking on a data owner, and the ID of the data owner is added into a revocable anonymous user list, so that the method can enable the authorizer to directly use the data, and the operation efficiency is improved. And a request for exposing the identity of a signer is provided to a third party for illegal data, an anonymity revocation algorithm is executed, and the identity of a data owner is exposed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data processing, and particularly relates to a cloud data security sharing method with revocable anonymity. BACKGROUND

[0002] With the in-depth development of information technology, the amount of data is expanding exponentially, and personal users and organizational units gradually weaken data sharing under the local or internal server storage mode and turn to cloud data security sharing for authorized users. From the cost-benefit perspective, local storage needs to continuously bear high operation and maintenance costs, including equipment updates, energy consumption, and human management. In contrast, cloud data sharing only needs to pay on demand, effectively reducing the cost expenditure. In terms of resource utilization efficiency, cloud data security sharing relies on distributed cloud storage and cloud parallel computing capabilities to promote efficient sharing of cloud data, improve data flow and utilization, and reduce resource waste and management costs caused by dispersed storage.

[0003] With the wide application of cloud data sharing, data security problems are increasingly prominent. In the data sharing process, due to the high requirement of data sharing scenarios for data privacy protection, data owners often take various technical means to conceal their real identities, so that their identities have strong anonymity features. However, the traditional data security management mechanism is difficult to effectively trace the real identity of the data owner in the case of strong anonymity. Once a data security problem occurs in the data sharing process, it is difficult to quickly locate the source of the problem and take targeted measures. Data users need to access cloud services through an open network to obtain shared data, and their access requests are extremely vulnerable to attacks of various types in the open network, which may lead to illegal access to cloud services and data theft, thereby exacerbating the security risks in the cloud storage environment.

[0004] One of the key technologies of existing cloud data security sharing is to achieve it through broadcast encryption technology. Its one-to-many feature has higher communication efficiency and wider application than point-to-point communication mode, and is an important means to ensure information security in broadcast communication. Identity-based broadcast encryption does not need to use public key certificates, simplifying the public key infrastructure, and thus has high practicability. In the identity-based broadcast encryption scheme, the data owner encrypts the plaintext message using the identity information of the authorized user, and then broadcasts the ciphertext on the public channel. Only authorized data users can correctly decrypt the broadcast ciphertext to obtain the plaintext message, and unauthorized data users cannot obtain any useful information. However, the lack of accountability for data owners in existing cloud data sharing schemes is still a pain point. SUMMARY

[0005] The present application aims to provide a cloud data security sharing method with revocable anonymity, aiming to solve the problem that it is difficult to effectively trace the real identity of the data owner in cloud data security sharing.

[0006] To achieve the above-mentioned purpose, the present application provides a cloud data security sharing method with revocable anonymity, comprising the following steps:

[0007] The revocable anonymity SM9 ring signature system initializes system parameters, outputs system public parameters, and at the same time, a third party initializes an identity set list and a revocable anonymity user list;

[0008] The signer randomly selects an identity set of n-1 users, executes the revocable anonymity SM9 ring signature algorithm, and outputs a signature;

[0009] The signer performs the signature encryption operation on the authorized set to obtain ciphertext;

[0010] The authorized party receives the ciphertext and can perform relevant operations on the data, and if there is a data operation problem, requests the third party to trace the identity of the data owner, and adds the data owner ID to the revocable anonymity user list.

[0011] The revocable anonymity SM9 ring signature system includes a key generation center, a data owner / signature initiator, a user, a third party and a cloud server.

[0012] The core function of the key generation center is to generate system public parameters and master private keys, and to calculate and distribute individual private keys for users, and the third party is responsible for generating the identity tag of the signer while the data owner generates the signature, and returns it to the user as an important parameter in the signature process, and when the arbitration request algorithm needs to be executed, the anonymity of the signer is revoked and the identity is disclosed.

[0013] The data owner is the signature initiator, responsible for encrypting and uploading data to the cloud server, and when data needs to be shared, the data owner will calculate the broadcast encryption algorithm for a specific group of receivers, and allow authorized receivers to decrypt and access.

[0014] The user is the authorized party, which obtains encrypted data from the cloud server, decrypts it with a personal private key to obtain signature data, and the user is not only a decrypter, but also responsible for verifying the signature, and when necessary, as the initiator of the request to the third party to revoke data anonymity, ensures the security and compliance of data sharing.

[0015] The cloud data security sharing method with revocable anonymity provided by the application can initialize system parameters of the revocable anonymity SM9 ring signature system, output system public parameters, and initialize an identity set list and a revocable anonymity user list by a third party at the same time; a signer randomly selects an identity set of n-1 users, executes a revocable anonymity SM9 ring signature algorithm, and outputs a signature; the signer executes a signature encryption operation on an authorized set to obtain ciphertext; an authorized party directly uses data by receiving the ciphertext, and if there is a data operation problem, requests the third party to track the identity of a data owner and adds the data owner ID to the revocable anonymity user list. The method combines the revocable anonymity SM9 ring signature technology and the broadcast encryption technology, can make the authorized party directly use data, and can make a request to the third party to expose the identity of the signer for illegal data, execute a revocation anonymity algorithm, expose the identity of the data owner, and solve the difficult accountability problem caused by the strong anonymity of the ring signature. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0017] Fig. 1 is a flow chart of a cloud data security sharing method with revocable anonymity provided by the application.

[0018] Fig. 2 is a schematic diagram of a revocable anonymity SM9 ring signature system. DETAILED DESCRIPTION

[0019] The embodiments of the application will be described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the application, and cannot be understood as a limitation of the application.

[0020] Please refer to Figs. 1-2 , the application provides a cloud data security sharing method with revocable anonymity, comprising the following steps:

[0021] S1 initializes system parameters of the revocable anonymity SM9 ring signature system, outputs system public parameters, and initializes an identity set list and a revocable anonymity user list by a third party at the same time;

[0022] In the embodiment of the present application, the SM9 ring signature system with revocable anonymity comprises a key generation center, a data owner / signature initiator, a user, a third party and a cloud server. The key generation center is responsible for generating system public parameters and master private key, and calculating and distributing individual private keys for users. The third party is responsible for generating identity tags of signers while the data owner generates signatures, and returns the identity tags to the user as an important parameter in the signature process, and executes arbitration request algorithm when needed to revoke the anonymity of the signer and disclose the identity of the signer. The data owner, i.e. the signature initiator, is responsible for encrypting data and uploading to the cloud server, and calculates broadcast encryption algorithm for a specific group of receivers when sharing data is needed, to ensure safe data transmission and allow authorized receivers to decrypt and access. The user, i.e. the authorized person, obtains encrypted data from the cloud server, decrypts the data with the personal private key to obtain signature data. The user is not only a decrypter, but also responsible for verifying the signature, and initiates the request to the third party to revoke the data anonymity when needed, to ensure the safety and compliance of data sharing.

[0023] System initialization, input security parameter λ, output system public parameter

[0024] Wherein is an N-order cyclic group, P1 is a generator of , P2 is a generator of , bilinear mapping e and its value domain Wherein Initialize user revocation list Key derivation function KDF, wherein l is the message length. The master private key msk is generated by the multi-KGC in the following manner.

[0025] Generate master private key share: each KGC j Generate a random number j={1≤j≤n} as its

[0026] Master private key share, calculate the corresponding master private key share P j , and make it public.

[0027] P j =s j ·P2

[0028] Master public key is

[0029]

[0030] Master private key is msk=d, and it is kept secret

[0031]

[0032] Key generation: KGC utilizes master private key and user identity ID i Compute its private key sk i .

[0033] v i = H1(ID i )

[0034]

[0035] Identity tag generation: the third party utilizes the identity of the signer to compute Q, and adds the identity into the set L,

[0036] Q = H3(ID π )

[0037] Compute the signature result of the third party by using its own private key,

[0038] Re = TS tsk (Q).

[0039] The signer S2 randomly selects the identity set of n-1 users, executes the ring signature algorithm of SM9 with revocable anonymity, and outputs sigma;

[0040] In the embodiment of the application, the signer pi randomly selects the identity set U n = {ID1, ID2, …, ID n} of n-1 users, executes the SM9 RSRA signature algorithm, and outputs sigma = (h1, R1, …, R n , psi).

[0041] The signer executes the following steps to generate the ring signature with revocable anonymity for the message M:

[0042] Compute the element in the group :

[0043] g0 = e(P1, P Pub ), g1 = e(sk π , P2), g2 = e(P1, P2)

[0044] When i = pi, compute

[0045]

[0046] When i ≠ pi, compute

[0047]

[0048] Compute

[0049]

[0050] Compute

[0051] w = ξ·η·μ·τ,

[0052] h1 = H2(U n ||M||w), l = (r - h1) mod p,

[0053] If l = 0, re-perform system initialization; otherwise, calculate

[0054] R π = [l]sk π

[0055]

[0056] Output the revocable anonymity ring signature σ = (h1, R1,..., R n , ψ) of the message M, and the third party generates the revocation label tag = (σ, Re).

[0057] SM9 RSRA signature verification: the verifier receives the message M' and the signature value σ' and performs the following verification:

[0058] Calculate σ' = (h1', R1',..., R n , ψ'), and verify whether the following conditions are met:

[0059] and If not, the verification fails; otherwise, perform the following calculation:

[0060] g0 = e(P1, P pub )

[0061]

[0062] h * = H2(U n ||M'||w')

[0063] Verify whether the following condition is met: If yes, the SM9 RSRA verification is passed, otherwise, the verification fails.

[0064] The S3 signer performs the σ encryption operation on the set of authorized persons to obtain the ciphertext;

[0065] In the embodiments of the present application, the signer π performs the σ encryption operation on the set of authorized persons AL = {ID1, ID2,..., ID n}, where n represents the number of authorized persons, and the specific operation steps are as follows:

[0066] Define the polynomial, where a i ,c i are computable polynomial coefficients;

[0067]

[0068] selecting a random number computing the elements in

[0069]

[0070] for any i∈[1,n],a i P1 is a master public key, therefore C0 is computable;

[0071] for any i={1,2,...,n}, compute

[0072]

[0073] since ap i (α) P1 is computable, therefore, t i is computable;

[0074] define a polynomial

[0075]

[0076] is the construction of a shared polynomial, where t n =1,

[0077] compute

[0078]

[0079] output the ciphertext cipher=(C0,C1,b0,b1,...,b n ).

[0080] S4 author receives the ciphertext directly using data, if data operation problem, request third party to data owner identity tracking, and data owner ID is added to the revocable anonymity user list.

[0081] In the embodiments of the present application, for the ciphertext cipher=(C0,C1,b0,b1,...,b n ) received by the author, the decrypter ID i calculates the plaintext according to the following steps:

[0082] First, use the private key to calculate t′ i , k′, K′, and output the decryption message M′.

[0083]

[0084] If ID i ∈ S, then t i ′ = t i ,k′ = k, K′ = K, further have, Can be correctly decrypted.

[0085] When the data user finds that the data has a problem, requests a third party to track the identity of the data provider, the third party calls SM9RSRA.RevoAno method, according to tag=(σ, Re) using its own public key tpk to Re signature gets Q=TV tpk (Re), the third party executes the hash value judgment j={1≤j≤n} tracking, if equal, j is the signer π, so as to expose its ID and add ID j To the malicious provider set ML.

[0086] The above only discloses a preferred embodiment of the cloud data security sharing method with revocable anonymity of the present application, of course, cannot be limited by the scope of the right of the present application, those skilled in the art can understand that all or part of the above-mentioned embodiments are implemented, and the equivalent changes made according to the claims of the present application still belong to the scope covered by the present application.

Claims

1. A cloud data security sharing method with revocable anonymity, characterized in that: The following steps are included: The SM9 ring signature system with revocable anonymity initializes system parameters and outputs system public parameters. At the same time, the third party initializes the identity set list and the revocable anonymity user list; The signer randomly selects a set of n-1 user identities, executes the SM9 ring signature algorithm with revocable anonymity, and outputs the signature; The signer performs the signature encryption operation on the set of authorized persons to obtain a ciphertext; The authorized person who receives the ciphertext can perform relevant operations on the data. If there is a problem with the data operation, the authorized person can request a third party to track the identity of the data owner and add the data owner ID to the revocable anonymity user list.

2. The cloud data secure sharing method with revocable anonymity according to claim 1, characterized in that ； The SM9 ring signature system with revocable anonymity includes a key generation center, a data owner / signature initiator, a user, a third party and a cloud server.

3. The method for securely sharing cloud data with revocable anonymity as claimed in claim 2, characterized in that ； The core function of the key generation center is to generate system public parameters and master private keys, and calculate and distribute individual private keys for users. The third party is responsible for generating the signer's identity tag when the data owner generates a signature, and returns it to the user as an important parameter in the signing process. It is also responsible for revoking the signer's anonymity and revealing his or her identity when the arbitration request algorithm needs to be executed.

4. The method for securely sharing cloud data with revocable anonymity according to claim 2, wherein: The data owner is the signature initiator, who is responsible for encrypting the data and uploading it to the cloud server. When data needs to be shared, the data owner will calculate the broadcast encryption algorithm for a specific group of recipients and allow authorized recipients to decrypt and access it.

5. The method for securely sharing cloud data with revocable anonymity as claimed in claim 1, characterized in that ； The user is the authorizer, who obtains encrypted data from the cloud server, decrypts it with a personal private key, and obtains signed data. The user is not only the decryptor, but also responsible for verifying the signature and, when necessary, acting as the initiator to request the third party to revoke the anonymity of the data, ensuring the security and compliance of data sharing.

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