CN109802828B - Cloud data integrity auditing method supporting public verification - Google Patents
Cloud data integrity auditing method supporting public verification Download PDFInfo
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- CN109802828B CN109802828B CN201811610572.6A CN201811610572A CN109802828B CN 109802828 B CN109802828 B CN 109802828B CN 201811610572 A CN201811610572 A CN 201811610572A CN 109802828 B CN109802828 B CN 109802828B
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Abstract
The technical scheme of the invention is constructed on a bilinear group, and adopts a verifiable hierarchical skip list to verify the storage position of data blocks, thereby providing the cloud data integrity auditing method which can achieve the security of a standard model, only depends on standard hypothesis and supports the public verification of any trusted third party. The data loss method and the data loss system solve the defect that in the prior art, a cloud storage service provider hides a data loss event and even possibly deletes user data maliciously, so that loss is caused to users, and the safety of the user stored data is improved.
Description
Technical Field
The invention belongs to the technical field of data integrity protection, and particularly relates to a cloud data integrity auditing method which achieves standard model security and supports public verification.
Background
Amazon introduced Amazon Web Services (AWS) in 2006. AWS eliminates the need for developers to create and manage their own server infrastructure by leasing amazon's own servers and storage space to others. Over the years, cloud storage has been fully developed and applied as the most successful application of cloud computing.
However, the cloud storage service provider is not managed by the user, is an untrusted object, and has a potential security risk. Cloud storage providers have the incentive to remove data that is not commonly used by users, thereby saving storage space for greater business benefits. According to the reported 'leading edge numerical control' platform, after 8 months of using the Tencent cloud server, data placed on the cloud server are all lost, and a so-called 'three-copy safety mechanism' of the Tencent cloud is also similar to a nominal one. The "leading edge numerical control" claims that the loss caused by data loss is more than 1100 ten thousand yuan.
The cloud storage service needs a safe, reliable and effective auditing mechanism to enable users to believe that the data stored on the cloud server is intact, and malicious cloud storage providers cannot forge the proof that the data still stores the user data, so that the integrity of the user data on the cloud service provider server is guaranteed.
The invention is a Chinese patent named as 'a method for auditing cloud storage data by an appointed verifier', and only supports the auditing of the cloud storage data by the appointed verifier, and the technical scheme of the method is constructed on a lattice algebraic structure, so that the method is not practical in practice.
Disclosure of Invention
The technical problem to be solved by the invention is to overcome the defects of the prior art and provide a cloud data integrity auditing method which can achieve the safety of a standard model, depends on standard assumption, has high safety and high operation speed and supports public verification.
The technical scheme adopted for solving the technical problems comprises the following steps:
1. system initialization
The data owner performs system initialization, inputs security parameters 1λOutputting a global public parameter pk and a private key sk;
the method for initializing the system comprises the following steps:
(1) setting safety parameters for the system 1λGenerating a p-order bilinear group G and a p-order bilinear group G by using a group generation methodTWherein p is a number satisfying the safety parameter 1λThe required prime number, bilinear mapped intoGTIs the target group.
(2) A verifiable hierarchical skip list T for verifying whether the blocks of data are actually stored is initialized.
(3) From p-order integer groups ZpWherein an integer alpha is randomly selected as a system private key to be kept secret.
(4) Is Boneh&Boyen public key signature scheme public key PK selectionsigAnd a private key SKsigPrivate key SKsigAnd (4) keeping secret.
(5) Randomly selecting two group elements G and v from a p-order bilinear group G, and randomly selecting one group element for constructing a hash function HG:{0,1}LL +1 Long vector of → G (G)0,g1,…,gL) Where L is the input bit length, a hash function H is setGIs m, to obtain
Where m [ i ] is the ith bit of m.
(6) Setting the private key SK to (α, SK)sig) From dataThe owner keeps secret, outputs the global public parameter pk of the system and discloses:
2. data storage
The data owner executes data storage, inputs a private key sk and data D to be stored, and outputs a data label T, a data signature sigma and a verifiable hierarchical skip list T head node HTSignature S (H)T)。
The data storage method comprises the following steps:
(1) inputting data D to be stored, sequentially splitting the data D to be stored into b blocks, and sequentially splitting each block into s segments, namely D ═ DijI is more than or equal to 1 and less than or equal to b, and j is more than or equal to 1 and less than or equal to s.
(2) Randomly selecting a bit string D of length LidAs an identifier of the data D to be stored, s elements u are randomly selected from a bilinear group G of order p1,…,us(ii) a Setting t0=Did||b||u1||…||usBy Boneh&Boyen public key signature scheme pair t0Signing is performed, wherein the private key used for signing is the private key SKsigThe resulting signature is S (t)0) Setting t as t0||S(t0) As a tag for the data D to be stored.
(3) For the ith data block, where 1 ≦ i ≦ b, from integer group ZpIn a random selection of integer riAnd tiSetting the signature σ of the file blockiIs (sigma)i,1,σi,2,ti) Where σ isi,1Is composed ofσi,2Is composed of(ii) a Set σ to { σiAs the signature of the whole data, where 1. ltoreq. i.ltoreq.b.
(4) All sigmai,2As storage objects, storeStoring to the bottom layer of verifiable hierarchical skip list T, and generating head node H thereof according to the storage rule of verifiable hierarchical skip list TTBy Boneh&Boyen public key signature scheme head node HTSigning is carried out to obtain a signature S (H)T)。
(5) Will be (D, t, sigma, S (H)T) Uploading to a cloud storage server for storage, and deleting the local data D.
3. A trusted third party issues a challenge
The data owner outsources the data auditing task to a trusted third party and sends the data label t to the trusted third party, and the trusted third party follows the integer group ZpRandomly selects an integer r from the set [1 … b ]]In which a subset I containing elements is randomly selected, for each I e I, from the group of integers ZpIn the random selection of integer viSet challenge C to (r, { i, v)iAnd } and sends to the cloud storage server.
4. Cloud storage server generation attestation
After receiving the challenge C of the trusted third party, the cloud storage server is based on the (D, t, sigma, S (H) of the storageT) The execution proof generation method generates a storage proof pi and sends the storage proof pi to a trusted third party.
The above proof generation method is as follows:
(1) the cloud storage server receives a challenge C ═ (r, { i, v) of the trusted third partyi}), set σ to (σ)1,σ2T'), where σ1Is composed ofσ2Is composed oft' is
(2) Cloud storage server sets storage proof pi toAnd sent to the trusted third partyWherein A is a reconstruction verifiable hierarchical skip list T head node HTAuxiliary information of (u)jIs composed of
5. Authentication by trusted third party
After receiving the storage certificate pi of the cloud storage server, the trusted third party carries out verification, if the verification is passed, the cloud storage server is stated to store the data of the user in a undamaged way, otherwise, the cloud storage server is stated to lose or damage the data of the user; and the cloud storage server is ensured not to generate the proof which can pass the verification under the condition of no data D.
The verification method is as follows:
(1) trusted third party first checksIf the verification is not successful, returning 0 immediately to indicate that the verification fails and quitting; if so, continue to the next step.
(2) Trusted third party utilization { σi,2}i∈CAnd A reconstruct verifiable hierarchical skip list T head node HTAnd verifies its signature S (H)T) If the reconstruction fails or the signature verification fails, immediately returning 0 to indicate that the verification fails and quitting; otherwise, the next step is continued.
(3) Trusted third party inspectionIf the verification is not successful, returning 0 immediately to indicate that the verification fails and quitting; if so, returning 1 indicates that the verification passed.
In the step (2) of initializing a verifiable hierarchical skip list T for verifying whether the data blocks are really stored in the system initialization 1, the number of the bottommost nodes of the verifiable hierarchical skip list T is set as b, wherein the b is the number of the blocks of the data D.
The technical scheme provided by the invention is constructed on a bilinear group, so that the cloud data integrity auditing method which can achieve the safety of a standard model, only depends on standard assumption and supports the public verification of any trusted third party is provided. The defects of the prior art are overcome, and the safety and the operation speed are improved.
Drawings
FIG. 1 is a flowchart of example 1 of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, but the present invention is not limited to the examples.
Example 1
The cloud data integrity auditing method supporting the public verification in the embodiment comprises the following steps:
1. system initialization
The data owner performs system initialization, inputs security parameters 1λOutputting a global public parameter pk and a private key sk;
the method for initializing the system comprises the following steps:
(1) setting safety parameters for the system 1λGenerating a p-order bilinear group G and a p-order bilinear group G by using a group generation methodTWherein p is a number satisfying the safety parameter 1λThe required prime number, bilinear mapped intoGTIs the target group.
(2) A verifiable hierarchical skip list T for verifying whether the blocks of data are actually stored is initialized.
It can be verified that the hierarchical skip list is cited from the article Dynamic changeable Data publication 2015, published in the journal of ACM Transactions on Information and System Security by Erway et al. And setting the number of the bottommost nodes of the verifiable hierarchical skip list T as b, wherein the b is the number of the blocks of the data D, and finishing the initialization of the verifiable hierarchical skip list T.
(3) From p-order integer groups ZpWherein an integer alpha is randomly selected as a system private key to be kept secret.
(4) Is Boneh&Boyen public key signature scheme public key PK selectionsigAnd a private key SKsigPrivate key SKsigKeeping secret;
the above Boneh & Boyen public key signature scheme is cited from Boneh and Boyen in 2004 in the paper Short Signatures Without Random Oracles, published by EUROCRYPT, European Union of cryptology. The purpose of using the Boneh & Boyen public key signature scheme is that it provides signature scheme security under a standard model.
(5) Randomly selecting two group elements G and v from a p-order bilinear group G, and randomly selecting one group element for constructing a hash function HG:{0,1}LL +1 Long vector of → G (G)0,g1,…,gL) Where L is the input bit length, a hash function H is setGIs m, to obtain
Where m [ i ] is the ith bit of m.
(6) Setting the private key SK to (α, SK)sig) And the data owner keeps secret, outputs a system global public parameter pk and discloses:
2. data storage
The data owner executes data storage, inputs a private key sk and data D to be stored, and outputs a data label T, a data signature sigma and a verifiable hierarchical skip list T head node HTSignature S (H)T)。
The data storage method comprises the following steps:
(1) inputting data D to be stored, sequentially splitting the data D to be stored into b blocks, and sequentially splitting each block into s segments, namely D ═ DijI is more than or equal to 1 and less than or equal to b, and j is more than or equal to 1 and less than or equal to s.
(2) Random selection of DidAs an identifier of the data D to be stored, s elements u are randomly selected from a bilinear group G of order p1,…,us(ii) a Is provided withSet t0=Did||b||u1||…||usBy Boneh&Boyen public key signature scheme pair t0Signing is performed, wherein the private key used for signing is the private key SKsigThe obtained signature is S (t)0) Setting t as t0||S(t0) As a tag for the data D to be stored.
(3) For the ith data block, where 1 ≦ i ≦ b, from integer group ZpIn a random selection of integer riAnd tiSetting the signature σ of the file blockiIs (sigma)i,1,σi,2,ti) Where σ isi,1Is composed ofσi,2Is composed of. Set σ to { σiAs the signature of the whole data, where 1. ltoreq. i.ltoreq.b.
(4) All sigmai,2As a storage object, storing the data to the lowest layer of the verifiable hierarchical skip list T, and generating a head node H of the verifiable hierarchical skip list T according to the storage rule of the verifiable hierarchical skip list TTBy Boneh&Boyen public key signature scheme head node HTSigning is carried out to obtain a signature S (H)T). Storing sigma with verifiable hierarchical skip list Ti,2The aim of (1) is to verify that the ith node at the bottom of the verifiable hierarchical skip list T stores exactly sigmai,2I.e. byThe signature of the ith data block and the signature of the ith data block are bound together, so that the substitute attack of the cloud storage server can be resisted.
(5) Will be (D, t, sigma, S (H)T) Uploading to a cloud storage server for storage, and deleting the local data D.
3. A trusted third party issues a challenge
The data owner outsources the data auditing task to a trusted third party and sends the data label t to the trusted third party, and the trusted third party follows the integer group ZpRandomly selects an integer r from the set [1 … b ]]In which a subset I containing elements is randomly selected, for each I e I, from the group of integers ZpIn the random selection of integer viSet challenge C to (r, { i, v)iAnd } and sends to the cloud storage server.
4. Cloud storage server generation attestation
After receiving the challenge C of the trusted third party, the cloud storage server is based on the (D, t, sigma, S (H) of the storageT) Executing the proof generation method to generate a storage proof pi and sending the storage proof pi to a trusted third party;
the above proof generation method is as follows:
(1) the cloud storage server receives a challenge C ═ (r, { i, v) of the trusted third partyi}), set σ to (σ)1,σ2T'), where σ1Is composed ofσ2Is composed oft' is
(2) Cloud storage server sets storage proof pi toAnd sending to a trusted third party, wherein A is a reconstructed verifiable hierarchical skip list T head node HTAuxiliary information of (u)jIs composed of
5. Authentication by trusted third party
After receiving the storage certificate pi of the cloud storage server, the trusted third party carries out verification, if the verification is passed, the cloud storage server is stated to store the data of the user in a undamaged way, otherwise, the cloud storage server is stated to lose or damage the data of the user; and the cloud storage server is ensured not to generate the proof which can pass the verification under the condition of no data D.
The verification method is as follows:
(1) trusted third party first checksIf the verification is not successful, returning 0 immediately to indicate that the verification fails and quitting; if so, continue to the next step.
(2) Trusted third party utilization { σi,2}i∈CAnd A reconstruct verifiable hierarchical skip list T head node HTAnd verifies its signature S (H)T) If the reconstruction fails or the signature verification fails, immediately returning 0 to indicate that the verification fails and quitting; otherwise, the next step is continued.
Claims (2)
1. A cloud data integrity auditing method supporting public verification is characterized by comprising the following steps:
(1) system initialization
The data owner performs system initialization, inputs security parameters 1λOutputting a global public parameter pk and a private key sk;
the system initialization method comprises the following steps:
1) setting safety parameters for the system 1λGenerating a p-order bilinear group G and a p-order bilinear group G by using a group generation methodTWherein p is a number satisfying the safety parameter 1λThe required prime number, bilinear mapped intoGTIs a target group;
2) initializing a verifiable hierarchical skip list T for verifying whether the storage data is truly partitioned;
3) from p-order integer groups ZpRandomly selecting an integer alpha as a system private key for confidentiality;
4) is Boneh&Boyen public key signature scheme public key PK selectionsigAnd a private key SKsigPrivate key SKsigKeeping secret;
5) randomly selecting two group elements G and v from a p-order bilinear group G, and randomly selecting one group element for constructing a hash function HG:{0,1}LL +1 Long vector of → G (G)0,g1,…,gL) Where L is the input bit length, a hash function H is setGIs m, to obtain
Where m [ i ] is the ith bit of m;
6) setting the private key SK to (α, SK)sig) And the data owner keeps secret, outputs a system global public parameter pk and discloses:
(2) data storage
The data owner executes data storage, inputs a private key sk and data D to be stored, and outputs a data label T, a data signature sigma and a verifiable hierarchical skip list T head node HTSignature S (H)T);
The data storage method comprises the following steps:
1) inputting data D to be stored, sequentially splitting the data D to be stored into b blocks, and sequentially splitting each block into s segments, namely D ═ DijI is more than or equal to 1 and less than or equal to b, and j is more than or equal to 1 and less than or equal to s;
2) randomly selecting a bit string D of length LidAs an identifier of the data D to be stored, s elements u are randomly selected from a bilinear group G of order p1,…,us(ii) a Setting t0=Did||b||u1||…||usBy Boneh&Boyen public key signature scheme pair t0Signing is performed, wherein the private key used for signing is the private key SKsigThe resulting signature is S (t)0) Setting t as t0||S(t0) A tag as data D to be stored;
3) for the ith data block, where 1 ≦ i ≦ b, from integer group ZpIn a random selection of integer riAnd tiSetting the signature σ of the file blockiIs (sigma)i,1,σi,2,ti) Where σ isi,1Is composed ofσi,2Is composed ofSet σ to { σiH, as a signature of the whole data, wherein i is more than or equal to 1 and less than or equal to b;
4) all sigmai,2As a storage object, storing the data to the lowest layer of the verifiable hierarchical skip list T, and generating a head node H of the verifiable hierarchical skip list T according to the storage rule of the verifiable hierarchical skip list TTBy Boneh&Boyen public key signature scheme head node HTSigning is carried out to obtain a signature S (H)T);
5) Will be (D, t, sigma, S (H)T) Uploading to a cloud storage server for storage, and deleting the local data D;
(3) a trusted third party issues a challenge
The data owner outsources the data auditing task to a trusted third party and sends the data label t to the trusted third party, and the trusted third party follows the integer group ZpIn the random selection of an integerFrom the set [1 … b]In which a subset I containing l elements is randomly selected, for each I e I, from the group of integers ZpIn the random selection of integer viSetting challenge C asAnd sending to a cloud storage server;
(4) cloud storage server generation attestation
After receiving the challenge C of the trusted third party, the cloud storage server is based on the (D, t, sigma, S (H) of the storageT) Executing the proof generation method to generate a storage proof pi and sending the storage proof pi to a trusted third party;
the certificate generation method comprises the following steps:
1) the cloud storage server receives the challenge of the trusted third partySetting sigma to (sigma)1,σ2T'), where σ1Is composed ofσ2Is composed oft' is
2) Cloud storage server sets storage proof pi toAnd sending to a trusted third party, wherein A is a reconstructed verifiable hierarchical skip list T head node HTAuxiliary information of (u)jIs composed of1≤j≤s;
(5) Authentication by trusted third party
After receiving the storage certificate pi of the cloud storage server, the trusted third party carries out verification, if the verification is passed, the cloud storage server is stated to store the data of the user in a undamaged way, otherwise, the cloud storage server is stated to lose or damage the data of the user; the cloud storage server is guaranteed to be incapable of generating a proof which can pass verification under the condition that data D do not exist;
the verification method comprises the following steps:
1) trusted third party first checksIf the verification is not successful, returning 0 immediately to indicate that the verification fails and quitting; if yes, continuing the next step;
2) trusted three-party utilization [ sigma ]i,2}i∈CAnd A reconstruct verifiable hierarchical skip list T head node HTAnd verifies its signature S (H)T) If the reconstruction fails or the signature verification fails, immediately returning 0 to indicate that the verification fails and quitting; otherwise, continuing the next step;
2. The cloud data integrity auditing method supporting public verification according to claim 1, characterized in that in (1) system initialization, step 2) initialization of a verifiable hierarchical skip list T for verifying whether the stored data is truly blocked further comprises setting the number of the bottommost nodes of the verifiable hierarchical skip list T as b, wherein b is the number of the blocks of the data D.
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