Privacy protection method for finding maximum value in blockchain-based decentralized scenario

Abstract

The application discloses a privacy protection method for finding maximum and minimum values in a decentralized scene based on a block chain, and relates to the fields of block chains and privacy calculation. S1: each participant determines a data range containing data held by all participants through a ring signature algorithm based on a block chain; S2: the data range is divided into a plurality of intervals, each participant checks whether the participant has data belonging to the interval from one side of the boundary, and exchanges checking information through privacy calculation, so that the maximum and minimum value intervals are found; and S3: the maximum and minimum values under ideal accuracy are found by continuously dividing the intervals in S2 and repeatedly performing S2.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blockchains, and in particular to a privacy protection method for finding maximum and minimum values in a decentralized scenario based on a blockchain. BACKGROUND

[0002] In federated learning, normalization is a common data preprocessing method, which refers to calculating the maximum and minimum data held by all participants to determine a data range, and then mapping all data of the participants to [0, 1] through the data range, simplifying the calculation and accelerating the convergence speed of the algorithm.

[0003] For federated computing normalization or other similar decentralized computing scenarios that require determination of a data range, a privacy protection method for finding maximum and minimum values is needed, so that no other data information is leaked in the calculation process except for the final published maximum and minimum values. However, the existing privacy maximum and minimum value finding techniques have problems such as the need to pre-set a data range, the ability to only solve discrete data, and the need to involve all data owned by each participant in the calculation process, which have great limitations and cannot provide effective privacy protection for maximum and minimum value calculation in the federated computing scenario. SUMMARY

[0004] In view of this, the embodiments of the present application provide a privacy protection method for finding maximum and minimum values in a decentralized scenario based on a blockchain, to solve the above technical problems and provide good privacy protection for cases where the data range is not pre-set and the data type may include continuous data.

[0005] According to a first aspect of the embodiments of the present application, a privacy protection method for finding maximum and minimum values in a decentralized scenario based on a blockchain is provided, including the following steps:

[0006] S1: Each participant determines a data range containing data held by all participants through a ring signature algorithm based on a blockchain;

[0007] S2: Divide the data range into several intervals, and each participant checks whether they have data belonging to the interval from one side of the boundary, and exchanges checking information through privacy finding to find the maximum and minimum value interval;

[0008] S3: Find the maximum and minimum values under ideal precision by continuously dividing the intervals in S2 and repeatedly performing S2.

[0009] Further, each participant determines a data range containing data held by all participants through a ring signature algorithm based on a blockchain, including:

[0010] S11: Each participant generates a pair of public and private keys for the blockchain-based ring signature algorithm according to the security parameters , and stores the public key in the smart contract of the blockchain;

[0011] S12: Any participant generates a random number TempLow, TempHigh , signs the random number with his own private key, sends it to the smart contract and verifies the legality by the smart contract, and the remaining participants obtain the legal random number from the smart contract RingSign(TempLow), RingSign(TempHigh) and compare it with their own data to obtain the data range.

[0012] Further, the blockchain-based ring signature algorithm in S1 uses the blockchain to replace the trusted third party or other anonymous mechanism of the traditional ring signature, and then uses the traditional ring signature protocol to ensure the legitimacy of the data and the anonymity of the transmission, and to ensure the privacy of the participants.

[0013] Further, any participant generates a random number, signs the random number with his own private key, sends it to the smart contract and verifies the legality by the smart contract, and the remaining participants obtain the legal random number from the smart contract and compare it with their own data to obtain the data range, including:

[0014] S121: Any participant generates a non-negative random number less than the minimum value of the data he holds as a temporary lower bound TempLow ;

[0015] S122: The participant signs the random number using the blockchain-based ring signature protocol, sends it to the smart contract of the blockchain and verifies the legality by the smart contract;

[0016] S123: Each participant obtains the legal temporary lower bound from the smart contract, compares the minimum value of the data he holds with TempLow ;

[0017] S124: The comparison results of each participant are calculated using the blockchain-based private AND protocol, and if the final result is 1, the temporary lower bound is taken as the lower bound of the data range Low , otherwise redo S121 to S123;

[0018] S125: Similarly, the upper bound of the data range is obtained High .

[0019] Further, the comparison results of each participant are calculated using the blockchain-based private AND protocol, including:

[0020] S1241: Each participant converts the data he holds as follows: if it is 0, it is converted into an arbitrary non-negative random number, if it is 1, it is converted into 0;

[0021] S1242: The data is arbitrarily divided into several parts, one part is kept by the participant and the remaining part is sent to other participants;

[0022] S1243: Each participant sums up the data he holds and the received data, and sends the result to the blockchain;

[0023] S1244: The smart contract sums up the received data, and if the final result is 0, the sum result is 1, otherwise the sum result is 0.

[0024] Further, the data range is divided into several intervals, each participant checks whether the data he holds belongs to the interval from one side of the boundary, and exchanges the checking information through the private sum protocol, so as to find the maximum and minimum value interval, including:

[0025] S21: According to the agreed binning coefficient, the data range is equally divided into several intervals;

[0026] S22: Starting from the interval with the smallest data range, it is determined whether the minimum value owned by a participant belongs to the interval by using the private interval confirmation protocol based on the blockchain;

[0027] S23: Each participant uses the private sum protocol to confirm whether the minimum value owned by a participant belongs to the interval, if no minimum value owned by any participant belongs to the interval, then the interval obtained by incrementing i is checked by using S22, that is, the interval with a larger data range, until the minimum value target interval is found [TargetHigh, TargetLow] ;

[0028] S24: Similarly, the maximum value target interval is obtained.

[0029] Further, the private interval confirmation protocol based on the blockchain is to use the private sum protocol based on the blockchain, each participant judges his own data, inputs 1 if it is in the interval, and inputs 0 if it is not in the interval, and then uses the private sum protocol based on the blockchain to calculate whether there is a minimum value of a participant in the interval.

[0030] Further, by continuously dividing the interval in S2 and repeatedly performing S2, the maximum and minimum values under the ideal precision are found, including:

[0031] S31: Compare the precision of the minimum value target interval TargetHigh - TargetLow with the target precision , if the precision is met, the lower boundary of the interval TargetLow is taken as the final minimum value result Min ;

[0032] S32: obtaining a minimum value target interval [TargetHigh, TargetLow] as a new data range [High', Low'] S2 is executed to obtain a new minimum value target interval [TargetHigh', TargetLow'] S31 is repeated until a minimum value meeting a target precision is obtained as a final minimum value result Min ;

[0033] S33: similarly, a final maximum value result is obtained Max .

[0034] According to a second aspect of the embodiments of the present application, an electronic device is provided, and the device comprises:

[0035] one or more processors;

[0036] a memory for storing one or more programs;

[0037] when the one or more programs are executed by the one or more processors, the one or more processors implement the method according to the first aspect.

[0038] According to a third aspect of the embodiments of the present application, a computer readable storage medium is provided, and the medium stores computer instructions, and the instructions are executed by a processor to implement the steps of the method according to the first aspect.

[0039] The technical solutions provided by the embodiments of the present application can include the following beneficial effects:

[0040] As can be seen from the above embodiments, the present application designs a complete set of maximum and minimum value solving protocol in a decentralized scenario based on encryption and confusion of information, so that the data of each node has the characteristics of being unbreakable and not exposing additional information in the process of information exchange, and the maximum and minimum values are obtained through aggregation and operation of these encrypted information, thereby achieving the effect of protecting the privacy of each node; by using the characteristics of decentralization and tamper resistance of the blockchain, the ring signature algorithm and the privacy sum algorithm based on the smart contract on the blockchain are designed, the algorithm process is simplified, and the security of the protocol is improved; by designing the data range confirmation process and the data precision confirmation process, the drawbacks of the existing privacy maximum and minimum value solving method, such as the need for data itself to have a data range feature and the ability to only process discrete data, are overcome, and the effect of completing privacy maximum and minimum value solving in a more general scenario is achieved.

[0041] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0042] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application.

[0043] Figure 1 is a flow chart of a privacy protection method for finding maximum and minimum values in a blockchain-based decentralized scenario according to an exemplary embodiment. DETAILED DESCRIPTION

[0044] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The description of the exemplary embodiments is intended to apply to any embodiment of the application, unless specifically stated otherwise. It is understood that the accompanying drawings are not intended to limit the application and that through conventional use they are intended to provide a conceptual illustration of the application.

[0045] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0046] Figure 1 is a flow chart of a privacy protection method for finding maximum and minimum values in a blockchain-based decentralized scenario according to an exemplary embodiment, as shown in Figure 1 the method can include the following steps:

[0047] S1: Each participant determines a data range containing data held by all participants through a ring signature algorithm based on a blockchain;

[0048] S2: Divide the data range into several intervals, and each participant checks whether he has data belonging to the interval from one side of the boundary, and exchanges checking information through a privacy protocol to find the maximum and minimum value interval;

[0049] S3: Find the maximum and minimum values under the ideal accuracy by continuously dividing the intervals in S2 and repeatedly performing S2.

[0050] From the above embodiments, it can be seen that the application realizes privacy protection in data exchange and operation process through a ring signature algorithm based on a blockchain and a privacy protocol. The data range confirmation step and the data accuracy confirmation process solve the processing of data without intrinsic range characteristics and continuous data.

[0051] In the implementation of S1: each participant determines a data range containing all the data held by the participants through a blockchain-based ring signature algorithm, including:

[0052] S11: Each participant generates a pair of public and private keys for the blockchain-based ring signature algorithm according to a security parameter, and stores the public key in the smart contract of the blockchain;

[0053] Specifically, initially, the participants can first negotiate the parameters needed in the subsequent agreement, which can include: the security parameter k for the blockchain-based secret sharing privacy sum, the binning coefficient for determining the number of partition intervals when improving the accuracy of the maximum and minimum value T , and the ideal accuracy of the finally obtained maximum and minimum value .

[0054] The blockchain-based ring signature algorithm uses the blockchain to replace the trusted third party or other anonymous mechanism of the traditional ring signature, and then uses the traditional ring signature protocol to ensure the legitimacy of the data and the anonymity of the transmission, and to ensure the privacy of the participants.

[0055] S12: Any participant generates a random number, signs it with their own private key, and sends it to the smart contract for verification of legitimacy, and the remaining participants obtain the legitimate random number from the smart contract and compare it with their own data to obtain the data range; this step can include the following sub-steps:

[0056] S121: Any participant generates a non-negative random number less than the minimum value of the data they hold as a temporary lower bound TempLow ;

[0057] S122: The participant signs the random number using the blockchain-based ring signature protocol to obtain RingSign(TempLow) , and then sends it to the smart contract of the blockchain for verification of legitimacy;

[0058] Specifically, n participants generate a pair of public and private keys for the blockchain-based ring signature protocol through a security parameter k, and the public and private key pairs , for the ring signature are stored in the smart contract of the blockchain and verified for legitimacy by the smart contract;

[0059] Assuming that the participants who need to perform ring signature have data: data to be signed, private key , hash function , and all public keys , the blockchain-based ring signature protocol can include the following sub-steps:

[0060] (1) Participants Generate a random number ;

[0061] (2) Participants use public key encryption get ;

[0062] (3) Participants calculate . Participants use private key decryption get ;

[0063] (4) Participants send to the smart contract using anonymous address, smart contract verification , if not equal, terminate the protocol.

[0064] S123: Each participant get the legal temporary lower bound from the smart contract TempLow , compare the minimum value in the data held by himself with the temporary lower bound;

[0065] S124: Use the blockchain-based private AND protocol to calculate the comparison results of each participant, if the final result is 1, the temporary lower bound is taken as the lower bound of the data range Low , otherwise redo S121 to S123;

[0066] S125: Similarly, get the upper bound of the data range High , so the data range is .

[0067] In S124, the comparison results of each participant are calculated by using the blockchain-based private AND protocol, including:

[0068] S1241: Each participant converts the data held by himself as follows: if it is 0, it is converted into any random number greater than 0, if it is 1, it is 0;

[0069] Specifically, each participant converts his own data as follows:

[0070] S1242: Split the data into several parts at will, keep one part and send the remaining part to other participants;

[0071] Specifically, the data is arbitrarily split into several parts, i.e. , is sent to , is calculated at the same time .

[0072] Specifically, the smart contract verifies whether is equal to and whether is equal to , and terminates the agreement if not.

[0073] S1243: Each participant sums up the data he holds and the data he receives and sends the result to the blockchain;

[0074] Specifically, each participant sums up all the data he receives, and sends the result to the blockchain.

[0075] S1244: The smart contract sums up the received data, and if the final result is 0, the sum result is 1, otherwise the sum result is 0.

[0076] In the specific implementation of S2, the data range is divided into several intervals, and each participant checks whether he has data belonging to the interval from one side of the boundary, and exchanges verification information through a private sum protocol to find the maximum and minimum interval, including:

[0077] S21: According to the agreed binning coefficient T , the data range is equally divided into T intervals;

[0078] Specifically, T the intervals are as follows: ,

[0079] S22: Starting from the smallest interval of the data range, determine whether there is a minimum value owned by a participant belonging to the interval using a blockchain-based private interval confirmation protocol;

[0080] Specifically, the blockchain-based private interval confirmation protocol is a blockchain-based private sum protocol, and each participant judges his own data, i.e. each participant checks from one side of the boundary, i.e. from (or ) Start to check whether there is data belonging to the interval in an incremental (or decremental) manner, input 1 if it is in the interval, and input 0 if it is not in the interval, and then use the privacy AND protocol based on the blockchain to calculate whether there is a minimum value of the participants in the interval.

[0081] S23: Each participant uses the privacy AND to confirm whether the minimum value owned by the participant belongs to the interval, and if there is no minimum value owned by any participant belonging to the interval, the interval with larger data range is checked by using S22 until the minimum value target interval is found.

[0082] S24: Similarly, the maximum value target interval is obtained.

[0083] In the implementation of S3, the maximum and minimum values under the ideal precision are found by continuously dividing the interval in S2 and repeatedly performing S2, including:

[0084] S31: Compare the minimum value target interval precision with the target precision, and if the precision is met, the lower boundary of the interval is taken as the final minimum value result.

[0085] Specifically, the minimum value target interval precision TargetHigh - TargetLow is compared with the target precision , and if the precision is met, the TargetLow is taken as the final minimum value result.

[0086] S32: Take the minimum value target interval as the new data range, perform S2 to obtain a new minimum value target interval, and repeat S31 until the minimum value meeting the target precision is obtained as the final minimum value result.

[0087] S33: Similarly, the final maximum value result is obtained.

[0088] For the device embodiment, since it basically corresponds to the method embodiment, the related parts can be referred to the part of the method embodiment. The device embodiment described above is only schematic, and the units shown as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or distributed on multiple network units. According to actual needs, part or all of the modules can be selected to achieve the purpose of the scheme of the present application. Those skilled in the art can understand and implement it without creative labor.

[0089] Correspondingly, the application further provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the privacy protection method for finding the maximum value in the decentralized scenario based on the block chain.

[0090] Correspondingly, the application further provides a computer readable storage medium, which stores computer instructions, and the instructions are executed by a processor to implement the privacy protection method for finding the maximum value in the decentralized scenario based on the block chain.

[0091] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0092] It should be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the appended claims.

Claims

1. A privacy protection method for finding the maximum value in a decentralized blockchain-based scenario, characterized in that, The method comprises the following steps: S1: each participant determines a data range containing data held by all participants through a blockchain-based ring signature algorithm; S2: the data range is divided into several intervals, and each participant checks whether the data belonging to the interval is from one side of the boundary and exchanges the checking information through a privacy XOR to find the maximum and minimum interval; S3: the maximum and minimum interval under the ideal accuracy is found by continuously dividing the interval in S2 and repeatedly performing S2; In the step S1, the blockchain-based ring signature algorithm is used to determine a data range containing data held by all participants, which comprises the following steps: S11: each participant generates a pair of public and private keys for the blockchain-based ring signature algorithm according to a security parameter, and stores the public key in the smart contract of the blockchain; S12: any participant generates a random number, signs the random number with the private key, and sends the signed random number to the smart contract for verification of the legality, and the remaining participants obtain the legal random number from the smart contract and compare the data with the legal random number to obtain the data range; In the step S12, any participant generates a random number, signs the random number with the private key, and sends the signed random number to the smart contract for verification of the legality, and the remaining participants obtain the legal random number from the smart contract and compare the data with the legal random number to obtain the data range, which comprises the following steps: S121: any participant generates a non-negative random number less than the minimum value of the data held by the participant as a temporary lower boundary; S122: the participant signs the random number with the blockchain-based ring signature protocol, sends the signed random number to the smart contract of the blockchain, and verifies the legality by the smart contract; S123: each participant obtains the legal temporary lower boundary from the smart contract, and compares the minimum value of the data held by the participant with the temporary lower boundary; S124: the comparison results of each participant are calculated by using the blockchain-based privacy XOR protocol, if the final result is 1, the temporary lower boundary is taken as the lower boundary of the data range, otherwise, S121 to S123 are redone; S125: similarly, the upper boundary of the data range is obtained.

2. The method of claim 1, wherein, In the step S1, the blockchain-based ring signature algorithm is used to replace the trusted third party or other anonymous mechanism of the traditional ring signature, and then the traditional ring signature protocol is used to ensure the legality of the data and the anonymity of the transmission, and to ensure the privacy of the participants.

3. The method of claim 1, wherein, In the step S124, the comparison results of each participant are calculated by using the blockchain-based privacy XOR protocol, which comprises the following steps: S1241: each participant converts the data held by the participant as follows: if it is 0, it is converted into any random number greater than 0, and if it is 1, it is converted into 0; S1242: the data is arbitrarily divided into several parts, one part is kept by the participant and the remaining parts are sent to other participants; S1243: each participant sums up the data held by the participant and the received data, and sends the result to the blockchain; S1244: the smart contract sums up the received data, and if the final result is 0, the XOR result is 1, otherwise the XOR result is 0.

4. The method of claim 1, wherein, The data range is divided into several intervals, each participant checks whether he has data belonging to the interval from one side of the boundary, and exchanges check information through private AND, to find the maximum and minimum interval, including: S21: According to the agreed binning coefficient, the data range is equally divided into several intervals; S22: Starting from the smallest interval of the data range, determine whether there is a minimum value owned by a participant belonging to the interval by using a blockchain-based private interval confirmation protocol; S23: Each participant uses a private AND confirmation protocol to determine whether there is a minimum value owned by a participant belonging to the interval, if there is no minimum value owned by any participant belonging to the interval, then use S22 to check the interval with larger data range, until the minimum value target interval is found; S24: Similarly, the maximum value target interval is obtained.

5. The method of claim 4, wherein, The blockchain-based private interval confirmation protocol uses a blockchain-based private AND protocol, each participant judges his own data, inputs 1 if it is in the interval, and inputs 0 if it is not in the interval, and then uses the blockchain-based private AND protocol to calculate whether there is a minimum value of a participant in the interval.

6. The method of claim 1, wherein, By continuing to divide the intervals in S2 and repeatedly performing S2, the maximum and minimum values under the ideal precision are found, including: S31: Compare the minimum value target interval precision with the target precision, if the precision is met, the lower boundary of the interval is taken as the final minimum value result, if the precision is not met, proceed to the next step; S32: Take the minimum value target interval as the new data range, perform S2 to get a new minimum value target interval, repeat S31 until the minimum value meeting the target precision is obtained as the final minimum value result; S33: Similarly, the final maximum value result is obtained.

7. An electronic device, comprising: Including: One or more processors; Memory for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method of any one of claims 1-6.

8. A computer readable storage medium having stored thereon computer instructions, wherein, The instructions are executed by the processor to implement the steps of the method of any one of claims 1-6.

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