Decentralized broadcast encryption method and device suitable for smart community, and medium

Abstract

The invention discloses a decentralized broadcast encryption method and device suitable for a smart community, and a medium, and relates to the technical field of data security. The method comprises the following steps: setting security parameters, and issuing public parameters by a management committee consisting of a plurality of community members; constructing a shared key based on the management committee; enabling the message sender to send the auxiliary information to the management committee, and calculating a time key according to the information sending time, the public parameter and the shared key; encrypting a message based on the time key, and issuing ciphertext data; and the management committee verifies the identity of the receiver by using the auxiliary information, and if the identity verification is passed, the receiver interacts with the management committee to obtain a time key, and then decrypts the ciphertext data. According to the invention, on the premise that a trusted center is not established, the members of the management committee send the time key to the user together, and the members of the committee do not need to interact with each other in the generation process of the time key.

Description

Technical Field

[0001] The present invention relates to the field of data security technology, and in particular to a decentralized broadcast encryption method, device and medium suitable for a smart community. Background Art

[0002] In a smart community, users need to broadcast messages to other legitimate users in the community. To ensure the confidentiality of the messages, the messages need to be encrypted before broadcasting. In existing solutions, a trusted center needs to be established to issue private keys or certificates to users, and the establishment and maintenance of a trusted center requires a lot of costs. Therefore, how to perform broadcast encryption without establishing a trusted center is a technical problem that needs to be solved urgently. Summary of the invention

[0003] The purpose of the present invention is to provide a decentralized broadcast encryption method, device and medium suitable for smart communities, which can enable members of the management committee to jointly send time keys to users without establishing a trusted center, and no interaction is required between committee members during the generation of the time keys.

[0004] To achieve the above object, the present invention provides the following solutions: A decentralized broadcast encryption method suitable for smart communities, comprising: Set security parameters and have a management committee consisting of multiple community members publish public parameters; constructing a shared key based on the management committee; Instruct the message sender to send the auxiliary information to the management committee, and calculate the time key according to the message sending time, public parameters and shared key; Encrypting the message based on the time key and publishing the ciphertext data; The management committee uses the auxiliary information to verify the identity of the recipient. If the identity verification is successful, the recipient interacts with the management committee to obtain the time key and then decrypts the ciphertext data.

[0005] Optionally, the security parameters are set and a management committee composed of multiple community members is instructed to publish the public parameters. The specific process includes: Setting security parameters , and a management committee consisting of t community members; Instruct the management committee to execute the following steps to publish public parameters: Choose a prime order The additive group and a two-generator ; Select four collision-robust hash functions ;in, Indicates less than a prime number The set of positive integers, Indicates the bit length of the message to be encrypted, Indicates the bit length of the selected random number; Set the message space to ; Publishing public parameters .

[0006] Optionally, the process of constructing a shared key based on the management committee includes: Let the i-th member of the management committee Perform the following steps to build a shared secret: Randomly select a polynomial of degree t-1 ;in, represents a t-1 degree polynomial, represents the coefficient of the t-1-order term, represents the t-1 order term, x Represents a variable whose value is an integer greater than or equal to 1 and less than or equal to t; calculate and , and broadcast it externally; Evaluating Polynomials , and sent to the jth committee member MC j ,in, ; Set up your own private key and the public key ; Set the committee master private key And the master public key ; Complete the shared key construction.

[0007] Optionally, the message sender sends the auxiliary information to the management committee, and calculates the time key according to the information sending time, the public parameters and the shared key. The specific process includes: Set the message sender ID S , auxiliary information Γ and information sending time T; wherein the auxiliary information Γ includes the validity period of the ciphertext and the identity information of the receiver; Message sender ID S Random Selection ,calculate , and and auxiliary information Γ to the members of the Management Committee; Indicates less than a prime number The set of positive integers; The i-th committee member MC i Random Selection ,calculate , and send Give the message sender ID S ; Message sender ID S calculate , , ; Message sender ID S Check the equation: Is it true? If not, refuse to send. If true, go to the next step. Message sender ID S calculate in, are the Lagrange coefficients; where Indicates the time key.

[0008] Optionally, the message is encrypted based on the time key, and the ciphertext data is published, and the specific process includes: Set Message ; Random Selection ,calculate ; Release ciphertext data .

[0009] Optionally, the management committee verifies the identity of the recipient using the auxiliary information. If the identity verification is successful, the recipient interacts with the management committee to obtain the time key, and then decrypts the ciphertext data. The specific process includes: Set the recipient ID e ; Receiver ID e Send your identity information to each member of the Management Committee; The i-th committee member MC i Check if it is satisfied If not, the recipient ID is rejected. e , if satisfied, send auxiliary information Give the recipient ID e ; Receiver ID e Random Selection ,calculate , and send it to the i-th committee member MC i ; The i-th committee member MC i calculate and with the receiver ID e Perform time key generation calculation, receiver ID e Obtain the time key TK; Receiver ID e calculate ; Receiver ID e Check if it is satisfied , if satisfied, the message m is accepted; if not satisfied, the ciphertext is rejected.

[0010] The present application also provides an electronic device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the above-mentioned decentralized broadcast encryption method applicable to a smart community.

[0011] The present application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the decentralized broadcast encryption method applicable to the smart community as described above.

[0012] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: The present invention discloses a decentralized broadcast encryption method, device and medium suitable for a smart community, the method comprising setting security parameters, and allowing a management committee composed of multiple community members to publish public parameters; constructing a shared key based on the management committee; allowing the message sender to send auxiliary information to the management committee, and calculating a time key based on the information sending time, public parameters and shared key; encrypting the message based on the time key and publishing ciphertext data; the management committee verifies the identity of the receiver using the auxiliary information, and if the identity verification is passed, the receiver interacts with the management committee to obtain a time password, and then decrypts the ciphertext data. The present invention can allow members of the management committee to jointly send time keys to users without establishing a trusted center, and there is no need for interaction between committee members during the generation of the time key. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0014] Figure 1 It is a flow chart of a decentralized broadcast encryption method applicable to a smart community of the present invention; Figure 2 This is a schematic diagram of the encryption logic in this embodiment. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] The purpose of the present invention is to provide a decentralized broadcast encryption method, device and medium suitable for smart communities, which can enable members of the management committee to jointly send time keys to users without establishing a trusted center, and no interaction is required between committee members during the generation of the time keys.

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1-Figure 2 As shown, the present invention provides a decentralized broadcast encryption method suitable for smart communities. On the one hand, there is no need to establish a trusted center. The members of the management committee jointly send time keys to users. There is no need for interaction between committee members during the generation of time keys. On the other hand, the scheme does not require the use of pairing operations, but only needs to be established on the elliptic curve group. In addition, the length of the ciphertext should also be a constant value and will not increase with the increase in the number of recipients, thereby reducing the cost of calculation and storage. The specific steps include: Step 100: Set security parameters and have a management committee consisting of multiple community members publish public parameters.

[0019] Step 200: Construct a shared key based on the management committee.

[0020] Step 300: Instruct the message sender to send the auxiliary information to the management committee, and calculate the time key according to the information sending time, public parameters and shared key.

[0021] Step 400: Encrypt the message based on the time key and publish the ciphertext data.

[0022] Step 500: The management committee verifies the identity of the recipient using the auxiliary information. If the identity verification is successful, the recipient interacts with the management committee to obtain the time password and then decrypts the ciphertext data.

[0023] Based on the above technical solution, the following specific implementation is provided.

[0024] Setup: Enter a security parameter , the Management Committee (MC) consisting of t community members performs the following steps: 1) Choose a prime order The additive group and a two-generator .

[0025] 2) Select four collision-resistant hash functions ;in, Indicates less than a prime number The set of positive integers, Indicates the bit length of the message to be encrypted, Indicates the bit length of the selected random number.

[0026] 3) Set the message space to .

[0027] 4) Publish public parameters .

[0028] Shared key generation: i-th committee member Perform the following steps: 1) Randomly select a polynomial of degree t-1 .

[0029] 2) Calculation and and broadcast it externally.

[0030] 3) Calculation , and send it to the jth committee member MC j , here .

[0031] 4) Set up the committee member’s own private key , public key ; Set the committee master private key , master public key .

[0032] Time key generation: At time T, the message sender IDs and management committee members perform the following steps: 1) At time T, the message sender ID S Send the auxiliary information Γ (including the validity period of the ciphertext, the identity information of the ciphertext recipient, etc.) to the management committee.

[0033] 2) Message sender ID S Random Selection ,calculate , and and auxiliary information Γ are sent to the members of the Management Committee.

[0034] 3) The i-th committee member Random Selection ,calculate , and send Give the message sender ID S。

[0035] 4) Message sender ID S calculate , , .

[0036] 5) Message sender ID S Check the equation: Is it true? If not, reject. Otherwise, continue with the following steps.

[0037] 6) Message sender ID S calculate in is the Lagrange coefficient. Among them, Is the message sender ID S Get the time key.

[0038] Encryption: Message sender ID S Perform the following steps to Encryption includes the following steps: 1) Random selection ,calculate .

[0039] 2) Publish ciphertext .

[0040] Decryption: Received ciphertext , perform the following steps: 1) Receiver ID e Send your identity information to each member of the management committee.

[0041] 2) The i-th committee member Check if If not, reject the ID e If true, send Give ID e .

[0042] 3) Receiver ID e Random Selection ,calculate , and send it to the i-th committee member .

[0043] 4) The i-th committee member calculate and with the receiver ID e Steps 3)-6) in execution time key generation), receiver ID e Get the time key TK.

[0044] 5) Receiver ID e calculate .

[0045] 6) Receiver ID e Check if , if true, accept the message m; otherwise, reject the ciphertext.

[0046] Therefore, through the above technical solution, the present application has the following beneficial effects: (1) The solution is based on a general elliptic group and does not require the use of pairing operations, which has higher efficiency. (2) The solution does not require the establishment of a trusted center, but rather the members of the management committee generate time keys for users. In the generation of time keys, the members do not need to interact with each other. (3) The length of the ciphertext is constant and does not increase with the increase in the number of recipients.

[0047] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0048] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A decentralized broadcast encryption method suitable for smart communities, characterized in that: include: Set security parameters and have a management committee consisting of multiple community members publish public parameters; constructing a shared key based on the management committee; Instruct the message sender to send the auxiliary information to the management committee, and calculate the time key according to the message sending time, public parameters and shared key; Encrypting the message based on the time key and publishing the ciphertext data; The management committee uses the auxiliary information to verify the identity of the recipient. If the identity verification is successful, the recipient interacts with the management committee to obtain the time key and then decrypts the ciphertext data.

2. The decentralized broadcast encryption method applicable to a smart community according to claim 1, characterized in that: The security parameters are set and the management committee composed of multiple community members publishes the public parameters. The specific process includes: Setting security parameters , and a management committee consisting of t community members; Instruct the management committee to execute the following steps to publish public parameters: Choose a prime order The additive group and a two-generator ; Choose four collision-robust hash functions ;in, Indicates less than a prime number The set of positive integers, Indicates the bit length of the message to be encrypted, Indicates the bit length of the selected random number; Set the message space to ; Publishing public parameters .

3. The decentralized broadcast encryption method applicable to a smart community according to claim 2, characterized in that: The specific process of constructing a shared key based on the management committee includes: Let the i-th member of the management committee Perform the following steps to build a shared secret: Randomly select a polynomial of degree t-1 ;in, represents a t-1 degree polynomial, represents the coefficient of the t-1-order term, represents the t-1 order term, x Represents a variable whose value is an integer greater than or equal to 1 and less than or equal to t; calculate and , and broadcast it externally; Evaluating Polynomials , and sent to the jth committee member MC j ,in, ; Set up your own private key and the public key ; Set the committee master private key And the master public key ; Complete the shared key construction.

4. The decentralized broadcast encryption method applicable to a smart community according to claim 3, characterized in that: The message sender sends the auxiliary information to the management committee, and calculates the time key according to the information sending time, public parameters and shared key. The specific process includes: Set the message sender ID S , auxiliary information Γ and information sending time T; wherein the auxiliary information Γ includes the validity period of the ciphertext and the identity information of the receiver; Message sender ID S Random Selection ,calculate , and and auxiliary information Γ to the members of the Management Committee; Indicates less than a prime number The set of positive integers; The i-th committee member MC i Random Selection ,calculate , and send Give the message sender ID S ; Message sender ID S calculate , , ; Message sender ID S Check the equation: Is it true? If not, refuse to send. If true, go to the next step. Message sender ID S calculate in, are the Lagrange coefficients; where Indicates the time key.

5. The decentralized broadcast encryption method applicable to a smart community according to claim 4, characterized in that: The message is encrypted based on the time key, and the ciphertext data is released. The specific process includes: Set Message ; Random Selection ,calculate ; Release ciphertext data .

6. The decentralized broadcast encryption method applicable to a smart community according to claim 5, characterized in that: The management committee verifies the identity of the recipient using the auxiliary information. If the identity verification is successful, the recipient interacts with the management committee to obtain the time key and then decrypts the ciphertext data. The specific process includes: Set the recipient ID e ; Receiver ID e Send your identity information to each member of the Management Committee; The i-th committee member MC i Check if it is satisfied If not, reject the recipient ID e , if satisfied, send auxiliary information Give the recipient ID e ; Receiver ID e Random Selection ,calculate , and send it to the i-th committee member MC i ; The i-th committee member MC i calculate and with the receiver ID e Perform time key generation calculation, receiver ID e Obtain the time key TK; Receiver ID e calculate ; Receiver ID e Check if it is satisfied , if satisfied, the message m is accepted; if not satisfied, the ciphertext is rejected.

7. An electronic device, characterized in that: It includes a memory and a processor, the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the decentralized broadcast encryption method suitable for a smart community according to any one of claims 1-6.

8. A computer-readable storage medium, characterized in that: It stores a computer program, which, when executed by a processor, implements a decentralized broadcast encryption method suitable for a smart community as described in any one of claims 1-6.

Images