A Decentralized Broadcast Encryption Method, Device and Medium Applicable to Smart Communities

Abstract

The present invention discloses a decentralized broadcast encryption method, device and medium applicable to a smart community, which relates to the technical field of data security. The method includes: setting security parameters and enabling a management committee composed of multiple community members to publish public parameters; constructing a shared key based on the management committee; enabling a message sender to send auxiliary information to the management committee and calculating a time key according to the message sending time, public parameters and the shared key; encrypting the message based on the time key and publishing ciphertext data; the management committee uses the auxiliary information to verify the identity of the receiver. If the identity verification is passed, the receiver interacts with the management committee to obtain the time key, and then decrypts the ciphertext data. The present invention can, without establishing a trusted center, enable the members of the management committee to jointly send a time key for a user, and there is no need for interaction among the committee members during the generation process of the time key.

Description

Technical Field

[0001] The present invention relates to the technical field of data security, and particularly to a decentralized broadcast encryption method, device and medium applicable to smart communities. Background Art

[0002] In a smart community, a user needs to broadcast a message to other legitimate users in the community. To achieve the confidentiality of the message, the message needs to be broadcast after encryption. In existing solutions, a trusted center needs to be established to issue private keys or certificates to users, and the establishment and maintenance of the trusted center require a large amount of cost. Therefore, how to perform broadcast encryption without establishing a trusted center is a technical problem that needs to be solved urgently at present. Summary of the Invention

[0003] The purpose of the present invention is to provide a decentralized broadcast encryption method, device and medium applicable to smart communities, which can, without establishing a trusted center, have members of the management committee jointly send a time key to a user, and there is no need for interaction among committee members during the generation process of the time key.

[0004] To achieve the above purpose, the present invention provides the following solutions:

[0005] A decentralized broadcast encryption method applicable to smart communities includes:

[0006] Setting security parameters, and having a management committee composed of multiple community members issue public parameters;

[0007] Constructing a shared key based on the management committee;

[0008] Having a message sender send auxiliary information to the management committee, and calculating a time key according to the information sending time, public parameters and the shared key;

[0009] Encrypting the message based on the time key and publishing ciphertext data;

[0010] The management committee uses the auxiliary information to verify the identity of the receiver. If the identity verification is passed, the receiver interacts with the management committee to obtain the time key, and then decrypts the ciphertext data.

[0011] Optionally, the process of setting security parameters and having a management committee composed of multiple community members issue public parameters specifically includes:

[0012] Setting security parameters , and forming a management committee with t community members;

[0013] Having the management committee execute the following steps to issue public parameters:

[0014] Select an additive group of prime order and a group generated by two generators ;

[0015] Select four collision-resistant hash functions ; Among them, represents the set of positive integers less than the prime number , represents the bit length of the message to be encrypted, represents the bit length of the randomly selected number;

[0016] Set the message space to ;

[0017] Publish the public parameters .

[0018] Optionally, constructing a shared key based on the management committee, the specific process includes:

[0019] Let the i-th member in the management committee perform the following steps to construct a shared key:

[0020] Randomly select polynomials t - 1 times ; Among them, represents a polynomial of degree t - 1, represents the coefficient of the term of degree t - 1, represents the term of degree t - 1, x represents a variable, taking an integer value greater than or equal to 1 and less than or equal to t;

[0021] Calculate and , and broadcast them externally;

[0022] Calculate the polynomial , and send it to the j-th member MC j , where ;

[0023] Set the private key of the member himself and the public key ;

[0024] Set the main private key of the committee and the main public key ;

[0025] Complete the construction of the shared key.

[0026] ​Optionally, the message sender is required to send auxiliary information to the management committee, and calculate a time key based on the information sending time, public parameters, and shared key. The specific process includes:

[0027] Set the message sender ID S , auxiliary information Γ, and the information sending time T; where the auxiliary information Γ includes the validity period of the ciphertext and the identity information of the recipient;

[0028] Message sender ID S Randomly select , calculate , and send and the auxiliary information Γ to the members of the management committee; Denotes the set of positive integers less than the prime number ;

[0029] The i-th member MC i Randomly select , calculate , and send to the message sender ID S ;

[0030] Message sender ID S Calculate , , ;

[0031] Message sender ID S Check the equation: Whether it holds. If it does not hold, reject the sending. If it holds, proceed to the next step;

[0032] Message sender ID S Calculate where is the Lagrange coefficient; where represents the time key.

[0033] Optionally, encrypt the message based on the time key and publish the ciphertext data. The specific process includes:

[0034] Set the message ;

[0035] Randomly select , calculate ;

[0036] Publish the ciphertext data .

[0037] Optionally, the management committee verifies the identity of the recipient using auxiliary information. If the identity verification is passed, the recipient interacts with the management committee to obtain a time key, and then decrypts the ciphertext data. The specific process includes:

[0038] Set the recipient ID e ;

[0039] Recipient ID e Send its own identity information to each member of the management committee;

[0040] The i-th member MC i Check whether it satisfies , if not, reject the recipient ID e , if satisfied, send the auxiliary information to the recipient ID e ;

[0041] Recipient ID e Randomly select , calculate , and send it to the i-th member MC i ;

[0042] The i-th member MC i Calculate , and perform time key generation calculation with the recipient ID e , the recipient ID e Obtain the time key TK;

[0043] Recipient ID e Calculate ;

[0044] Recipient ID e Check whether it satisfies , if satisfied, accept the message m; if not, reject the ciphertext.

[0045] This application also provides an electronic device, including 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 applicable to the smart community according to the above.

[0046] This application also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the decentralized broadcast encryption method applicable to the smart community as described above.

[0047] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0048] The present invention discloses a decentralized broadcast encryption method, device and medium applicable to smart communities. The method includes setting security parameters and enabling a management committee composed of multiple community members to publish public parameters; constructing a shared key based on the management committee; enabling a message sender to send auxiliary information to the management committee and calculating a time key according to the message sending time, public parameters and shared key; encrypting the message based on the time key and publishing ciphertext data; the management committee uses the auxiliary information to verify the identity of the receiver. If the identity verification passes, the receiver interacts with the management committee to obtain a time password, and then decrypts the ciphertext data. The present invention can, without establishing a trusted center, enable the members of the management committee to jointly send a time key for users, and there is no need for interaction between the committee members during the generation process of the time key. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0050] Figure 1 It is a schematic flow chart of the decentralized broadcast encryption method applicable to smart communities of the present invention;

[0051] Figure 2 It is a schematic diagram of the encryption logic in this embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0053] The purpose of the present invention is to provide a decentralized broadcast encryption method, device and medium applicable to smart communities, which can, without establishing a trusted center, enable the members of the management committee to jointly send a time key for users, and there is no need for interaction between the committee members during the generation process of the time key.

[0054] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0055] As Figure 1 - Figure 2As shown in the figure, the present invention provides a decentralized broadcast encryption method applicable to 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, and there is no need for interaction among the committee members during the generation of time keys. On the other hand, the scheme does not require pairing operations, is only based on an elliptic curve group, and the length of the ciphertext should also be fixed and will not increase with the increase in the number of receivers, thereby reducing the calculation and storage costs. The specific steps include:

[0056] Step 100: Set security parameters and let the management committee composed of multiple community members publish public parameters.

[0057] Step 200: Construct a shared key based on the management committee.

[0058] Step 300: Let the message sender send auxiliary information to the management committee and calculate the time key according to the message sending time, public parameters, and shared key.

[0059] Step 400: Encrypt the message based on the time key and publish the ciphertext data.

[0060] Step 500: The management committee uses the auxiliary information to verify the identity of the receiver. If the identity verification passes, the receiver interacts with the management committee to obtain the time password, and then decrypts the ciphertext data.

[0061] Based on the above technical solutions, the following specific implementation manners are provided.

[0062] Setting: Input a security parameter , and the management committee (MC) composed of t community members performs the following steps:

[0063] 1) Select an additive group of prime order and two generators .

[0064] 2) Select four collision-resistant hash functions ; where, represents the set of positive integers less than the prime number , represents the bit length of the message to be encrypted, represents the bit length of the selected random number.

[0065] 3) Set the message space as .

[0066] 4) Publish the public parameters .

[0067] Shared key generation: The i-th committee member Performs the following steps:

[0068] 1) Randomly select a polynomial of degree t - 1 .

[0069] 2) Calculate and , and broadcast them externally.

[0070] 3) Calculate , and send it to the j-th committee member MC j , where .

[0071] 4) Set the committee member's own private key , public key ; Set the committee's master private key , master public key .

[0072] Time key generation: At time T, the message sender ID and the members of the management committee perform the following steps:

[0073] 1) At time T, the message sender ID S sends the auxiliary information Γ (including the validity period of the ciphertext, the identity information of the ciphertext receiver, etc.) to the management committee.

[0074] 2) The message sender ID S randomly selects , calculates , and sends and the auxiliary information Γ to the members of the management committee.

[0075] 3) The i-th committee member randomly selects , calculates , and sends to the message sender ID S。

[0076] 4) The message sender ID S calculates , , .

[0077] 5) The message sender ID S checks the equation: Does it hold? If not, reject. Otherwise, continue with the following steps.

[0078] 6) The message sender ID S calculates where are the Lagrange coefficients. Among them, Is the message sender ID S Obtain the time key.

[0079] Encryption: Message sender ID S Execute the following steps to encrypt the message including the following steps:

[0080] 1) Randomly select and calculate .

[0081] 2) Publish the ciphertext .

[0082] Decryption: Upon receiving the ciphertext , execute the following steps:

[0083] 1) The receiver ID e Sends its own identity information to each member of the management committee.

[0084] 2) The i-th member Checks if . If not, rejects the ID e . If so, sends to the ID e .

[0085] 3) The receiver ID e Randomly selects and calculates , and sends it to the i-th member .

[0086] 4) The i-th member Calculates , and executes steps 3) - 6) in the time key generation with the receiver ID e . The receiver ID e Obtains the time key TK.

[0087] 5) The receiver ID e Calculates .

[0088] 6) The receiver ID e Checks if . If so, accepts the message m; otherwise, rejects the ciphertext.

[0089] Therefore, through the above technical solutions, 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, thus having higher efficiency. (2). In the solution, there is no need to set up a trusted center. Instead, the members of the management committee generate time keys for users, and there is no need for interaction among the members during the generation of time keys. (3). The length of the ciphertext is constant and does not increase with the increase in the number of recipients.

[0090] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0091] Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only for helping to understand the core idea of the present invention. At the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation on the present invention.

Claims

1. A decentralized broadcast encryption method applicable to smart communities, characterized in that, Including: Set security parameters and let the management committee composed of multiple community members publish public parameters; Construct a shared key based on the management committee; Let the message sender send auxiliary information to the management committee and calculate a time key according to the message sending time, public parameters, and shared key; Encrypt the message based on the time key and publish the ciphertext data; The management committee uses the auxiliary information to verify the identity of the receiver. If the identity verification passes, the receiver interacts with the management committee to obtain the time key, and then decrypts the ciphertext data; The setting of security parameters and letting the management committee composed of multiple community members publish public parameters specifically includes: Set security parameters , and a management committee is composed of t community members; Let the management committee execute the following steps to publish public parameters: Select an additive group of prime order and a generator ; ; Select four collision-resistant hash functions ; among them, represents the set of positive integers less than the prime number , represents the bit length of the message to be encrypted, represents the bit length of the randomly selected number; Set the message space to ; Publish public parameters ; The construction of the shared key based on the management committee specifically includes: Let the \(i\)-th member of the management committee perform the following steps to construct a shared key: A polynomial randomly selected t - 1 times ; where represents a polynomial of degree t - 1, represents the coefficient of the term of degree t - 1, represents the term of degree t - 1, x represents a variable, taking an integer value greater than or equal to 1 and less than or equal to t; Calculate and and broadcast externally; Calculate the polynomial and send it to the j-th committee member MC j , where ; Set the private key of the committee member and the public key ; Set the committee master private key and the master public key ; Complete the construction of the shared key; The process of letting the message sender send auxiliary information to the management committee and calculating the time key according to the message sending time, public parameters, and shared key specifically includes: Set the message sender ID S , auxiliary information Γ, and the message sending time T; among them, the auxiliary information Γ includes the validity period of the ciphertext and the identity information of the recipient; Message sender ID S Random selection , calculate , and send and the auxiliary information Γ to the members of the management committee; Denote the set of positive integers less than the prime number ; The i-th committee member MC i Randomly select , calculate , and send to the message sender ID S ; Message sender ID S Calculate , , ; Message sender ID S Check the equation: Whether it holds. If not, reject the sending. If it holds, proceed to the next step; Message sender ID S Calculation Wherein is the Lagrange coefficient; wherein represents the time key.

2. The decentralized broadcast encryption method applicable to the smart community according to claim 1, wherein The process of encrypting the message based on the time key and publishing the ciphertext data specifically includes: Set message ; Randomly select , calculate ; Release ciphertext data .

3. The decentralized broadcast encryption method applicable to the smart community according to claim 2, wherein The process of the management committee using the auxiliary information to verify the identity of the receiver. If the identity verification passes, the receiver interacts with the management committee to obtain the time key, and then decrypts the ciphertext data specifically includes: Set recipient ID e ; Receiver ID e Send its own identity information to each member of the management committee; The i-th committee member MC i Check if it meets , if it does not meet, reject the recipient ID e , if it meets, send the auxiliary information to 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 perform time key generation calculation with the recipient ID e to obtain the time key TK; e The recipient ID Recipient ID e Calculate ; Receiver ID e Check if it meets , if it meets, accept the message m; if it does not meet, reject the ciphertext.

4. An electronic device, characterized in that, Including 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 for a smart community according to any one of claims 1-3.

5. A computer-readable storage medium, characterized in that, It stores a computer program, and when the computer program is executed by a processor, it implements the decentralized broadcast encryption method for a smart community according to any one of claims 1-3.

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