A privacy computing method and system based on TEE and FHE technology

Abstract

The application discloses a privacy calculation method and system based on TEE and FHE technology. The method first determines a key management party and generates a key in a trusted area; after the key is generated, the key management party sends a public key to other participants in a non-trusted area; a data party encrypts obtained plaintext data by using the public key and sends the ciphertext data to a calculation party; the calculation party jointly calculates the ciphertext data to obtain a ciphertext result and sends the ciphertext result to the key management party; finally, the key management party obtains the ciphertext result in the non-trusted area, decrypts the ciphertext result to obtain plaintext result in the trusted area, and sends the plaintext result to other data parties in the non-trusted area. The method improves the security of FHE application, reduces the trust assumption requirement for the key management party, and balances the running performance and security cost of the FHE application.

Description

Technical Field

[0001] This invention relates to the field of data processing, and in particular to a privacy computing method and system based on TEE and FHE technologies. Background Technology

[0002] Fully homomorphic encryption (FHE) is a novel privacy protection technology that enables computation based on encrypted data and is commonly used in applications such as outsourced computing power. An FHE application involves multiple participants: data providers offer raw plaintext data and encrypt it; computation providers offer computing power to perform ciphertext computations; and a key manager generates the FHE algorithm's public and private keys and decrypts the ciphertext result to obtain the final plaintext result. The basic steps of an FHE application include: the key manager randomly generates a public and private key based on the input algorithm parameters; the key manager sends the public key to each data provider and computation provider; each data provider sends its ciphertext data to the computation provider; the computation provider performs encrypted computations on the ciphertext data to obtain the ciphertext result; and the key manager decrypts the ciphertext result using its private key to obtain the plaintext result, which is then sent to each data provider.

[0003] In the FHE application described above, the trust assumption of the key manager is crucial to the data security of all other participants. If the private key held by the key manager is leaked, it means that all encrypted data from other participants will be exposed as original encrypted data. Therefore, the core security aspect of FHE applications lies in ensuring the security of the private key.

[0004] Currently, there are two private key protection schemes to ensure the data security of FHE applications: 1) Selecting a trusted participant as the key manager, responsible for key generation and management. This scheme assumes that the key manager will neither actively engage in malicious activities (collusion with other participants) to leak the private key, nor passively engage in malicious activities (such as being attacked) leading to private key leakage; 2) Managing the private key through MPC technology: Simply put, the private key is kept by multiple participants, each holding a portion of it. The complete key can only be recovered when all participants cooperate. This scheme assumes that malicious actions by some participants will not lead to key leakage, thus ensuring the data security of other non-malicious parties.

[0005] Of the two FHE private key protection schemes mentioned above, the first scheme assumes too much trust in the participants, making it difficult to gain the complete trust of other data parties in reality, thus affecting the willingness of each participant to cooperate; the second scheme assumes low trust and high security, but the additional computational overhead of implementing key protection through MPC seriously affects the original FHE computational performance. Summary of the Invention

[0006] Based on this, the embodiments of this application provide a privacy computing method and system based on TEE and FHE technologies. Key management can be achieved through TEE technology, which increases key security, reduces the trust assumptions required of the key manager, enhances the security protection capabilities of the key manager, and reduces its attack surface from the entire operating environment of the participants to the TEE.

[0007] Firstly, a privacy-preserving computation method based on TEE and FHE technologies is provided, the method comprising:

[0008] In a fully homomorphic encryption environment, a key manager is identified among the participants, and a key is generated within a trusted area by the key manager; wherein the key includes a private key and a public key;

[0009] After the key is generated, the key manager calls a network sending function in an untrusted area to send the public key to other participants; these other participants include data providers and computation providers.

[0010] The data provider obtains the plaintext data of the target computing task, encrypts the obtained plaintext data using the public key to obtain ciphertext data, and sends the ciphertext data to the computing provider.

[0011] The computing party performs joint computation on the ciphertext data sent by each data party to obtain the ciphertext result of the target computing task, and sends the ciphertext result to the key management party;

[0012] In the untrusted area, the key manager decrypts the ciphertext result uploaded by the computing party based on the function call obtained by calling the function, obtains the plaintext result of the target computing task in the trusted area, and then calls the network sending function in the untrusted area to send the plaintext result to other data parties.

[0013] Optionally, a key manager is determined among the participants in the fully homomorphic encryption environment, and the key manager generates a key within a trusted area, including:

[0014] Generate an FHE private key based on the security parameters and store the private key in a fully homomorphic encrypted environment;

[0015] Generate a corresponding FHE encryption public key using the FHE private key;

[0016] Determine the relinear key required in the FHE private key generation ciphertext calculation process;

[0017] The FHE encryption public key and the re-linear key are sent to the other participants.

[0018] Optionally, a key manager is determined among the participants in the fully homomorphic encryption environment, and the key is generated within a trusted area by the key manager. The method further includes:

[0019] The trusted and untrusted areas of the key management party are determined; wherein the trusted areas include at least the encrypted memory area and the encrypted hardware chip area.

[0020] Optionally, the trusted and untrusted areas of the key manager are determined, including:

[0021] Trusted regions are identified using Intel SGX TEE technology, while other regions of memory are designated as untrusted regions.

[0022] Secondly, a privacy computing system based on TEE and FHE technologies is provided, the system comprising:

[0023] A key manager is responsible for generating keys within a trusted area. After key generation, the key manager calls a network sending function in an untrusted area to send the public key to other participants. After obtaining the ciphertext structure uploaded by the computation party, the key manager decrypts the ciphertext result uploaded by the computation party in the trusted area based on the ciphertext result obtained by calling the function, and then calls the network sending function in the untrusted area to send the plaintext result to other data parties. The key includes a private key and a public key, and the other participants include the data party and the computation party. The key manager is determined from among the participants in the fully homomorphic encryption environment.

[0024] The data provider is used to obtain plaintext data of the target computing task, encrypt the obtained plaintext data using a public key to obtain ciphertext data, and send the ciphertext data to the computing provider.

[0025] The computational party is used to perform joint computation on the ciphertext data sent by each data party to obtain the ciphertext result of the target computation task, and then send the ciphertext result to the key management party.

[0026] Optionally, the key manager generates the key within a trusted area, including:

[0027] Generate an FHE private key based on the security parameters and store the private key in a fully homomorphic encrypted environment;

[0028] Generate a corresponding FHE encryption public key using the FHE private key;

[0029] Determine the relinear key required in the FHE private key generation ciphertext calculation process;

[0030] The FHE encryption public key and the re-linear key are sent to the other participants.

[0031] Optionally, the key manager may also include:

[0032] Determine trusted and untrusted regions; wherein the trusted regions include at least an encrypted memory region and an encrypted hardware chip region.

[0033] Optionally, the trusted and untrusted areas of the key manager are determined, including:

[0034] Trusted regions are identified using Intel SGX TEE technology, while other regions of memory are designated as untrusted regions.

[0035] Thirdly, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the privacy computing method based on TEE and FHE technologies described in any of the first aspects above.

[0036] Fourthly, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the privacy computing method based on TEE and FHE technologies described in any of the first aspects above.

[0037] In the technical solution provided in this application embodiment, a key manager is first determined among the participants in the fully homomorphic encryption environment. The key manager generates a key in a trusted area. After key generation, the key manager calls a network sending function in an untrusted area to send the public key to other participants. The data party obtains the plaintext data of the target computing task, encrypts the obtained plaintext data using the public key to obtain ciphertext data, and sends the ciphertext data to the computing party. The computing party performs joint computation on the ciphertext data sent by each data party to obtain the ciphertext result of the target computing task, and sends the ciphertext result to the key manager. Finally, the key manager decrypts the ciphertext result uploaded by the computing party in the trusted area based on the ciphertext result obtained by calling the function in the untrusted area to obtain the plaintext result of the target computing task, and calls a network sending function in the untrusted area to send the plaintext result to other data parties.

[0038] The beneficial effects of the technical solutions provided in this application include at least improving the security of FHE applications, reducing the trust assumptions required for key management, and balancing the performance and security costs of FHE applications. Attached Figure Description

[0039] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0040] Figure 1 A flowchart illustrating the steps of a privacy computation method based on TEE and FHE technologies provided in this application embodiment;

[0041] Figure 2 This is a schematic diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0043] In the description of this invention, the terms “comprising,” “having,” and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are expressly listed, but may also include other steps or units that are not expressly listed but are inherent to these processes, methods, products, or apparatuses, or steps or units added based on further optimizations of the inventive concept.

[0044] To facilitate understanding of this embodiment, a privacy computing method based on TEE and FHE technologies disclosed in this application will first be described in detail.

[0045] In this application, FHE refers to Fully Homomorphic Encryption, a novel privacy protection technology that enables computation based on encrypted data and is commonly used in applications such as outsourced computing power. FHE applications involve multiple parties: 1) Data provider: providing the original plaintext data and encrypting it; 2) Computation provider: providing computing power to perform ciphertext computation; 3) Key manager: generating the public and private keys for the FHE algorithm and decrypting the ciphertext result to obtain the final plaintext result.

[0046] In FHE applications, key management is achieved through TEE (Trusted Execution Environment) technology, which increases key security, reduces the trust assumptions required of the key manager, and enhances the security protection capabilities of the key manager, thus narrowing its attack surface from the entire operating environment of the participants to the TEE (a trusted environment is generally a specific area in the operating environment, such as an encrypted memory area / encrypted hardware chip area, etc.).

[0047] Please refer to Figure 1 The diagram illustrates a flowchart of a privacy computing method based on TEE and FHE technologies provided in this application embodiment. The method may include the following steps:

[0048] Step 101: Identify a key manager among the participants in the fully homomorphic encryption environment, and generate a key within a trusted area through the key manager.

[0049] The keys include a private key and a public key. The trusted area includes at least an encrypted memory area and an encrypted hardware chip area.

[0050] Specifically, the participating party that supports TEE is selected as the key manager, and the following operations are performed within the TEE security zone:

[0051] Step 1011: Generate an FHE private key based on the security parameters and store the private key in a fully homomorphic encryption environment.

[0052] Specifically, an FHE private key, denoted as sk, is generated based on security parameters. sk is stored in the TEE environment.

[0053] Step 1012: Generate the corresponding FHE encryption public key using the FHE private key.

[0054] Among them, an FHE encryption public key is generated based on sk, denoted as enc_key;

[0055] Step 1013: Determine the relinear key required for the FHE private key ciphertext generation calculation process;

[0056] Among them, the relinear key / bootstrap key used in the ciphertext calculation process based on sk is denoted as eva_key;

[0057] Step 1014: Send the FHE encryption public key and the re-linear key to the other participants.

[0058] The encryption public key `enc_key` and the re-linear key / bootstrap key `eva_key` are collectively referred to as the public key `pk`. The TEE sends `pk` to other data providers and computation providers.

[0059] In this embodiment, the key manager generates a private / public key within the SGX Enclave trusted area and runs the `generate_sk` function to obtain the private key `sk` for the current computation task. Then, using `sk` as input, the `generate_pk` function is run to obtain the public key `pk` corresponding to `sk`.

[0060] Step 102: After the key is generated, the key manager calls the network sending function in the untrusted area to send the public key to other participants.

[0061] Other participants include data providers and computing providers.

[0062] In this embodiment, the public key is sent to other data parties and computation parties by calling the network sending function send_pk within the untrusted area of ​​the SGX Enclave.

[0063] Step 103: The data provider obtains the plaintext data of the target computing task, encrypts the obtained plaintext data using the public key to obtain ciphertext data, and sends the ciphertext data to the computing provider.

[0064] The target computation task is the current computation task obtained. The data provider uses the received public key enc_key to encrypt its plaintext data, obtaining ciphertext data cipher_data, and then sends cipher_data to the computation provider.

[0065] In this embodiment, the data provider calls the FHE algorithm to encrypt its plaintext data to obtain ciphertext data cipher_data, and then sends the ciphertext data to the computing provider.

[0066] Step 104: The computing party performs joint computation on the ciphertext data sent by each data party to obtain the ciphertext result of the target computation task, and sends the ciphertext result to the key management party.

[0067] In this process, the computing party aggregates the ciphertext data from multiple participants, performs ciphertext calculations to obtain the ciphertext result, and then sends the ciphertext result to the key management party.

[0068] In this embodiment, the computing party calls the FHE algorithm to jointly compute the cipher data cipher_data of each data party to obtain the ciphertext result of the current computing task, and sends the ciphertext result to the key management party.

[0069] Step 105: In the untrusted area, the key manager decrypts the ciphertext result uploaded by the computing party based on the function call obtained by calling the function, and obtains the plaintext result of the target computing task in the trusted area. Then, in the untrusted area, the key manager calls the network sending function to send the plaintext result to other data parties.

[0070] In this process, the key manager uses the private key sk within the TEE secure area to decrypt the ciphertext result to obtain the plaintext calculation result, and then sends the plaintext result to each data party.

[0071] In this embodiment, the key manager calls the rcv_cipher function in the untrusted region to obtain the ciphertext result of the current computation task, calls the dec_cipher_data function in the SGX Enclave trusted region to decrypt the ciphertext result to obtain the plaintext result of the current computation task, and then calls the send_plain_rlt function in the untrusted region to send the plaintext result to other data parties.

[0072] In optional embodiments of this application, taking Intel SGX TEE technology and SEAL FHE as examples, the core code example for key management via TEE technology is as follows:

[0073]

[0074]

[0075] In summary, this application demonstrates that all computational operations involving the FHE private key sk during FHE applications must be performed within the secure TEE area. Specifically, this includes generating the private key, generating the public key, and decrypting the ciphertext. This improves the security of FHE applications, reduces the trust requirements on the key management party, and balances the operational performance and security costs of FHE applications.

[0076] This application also provides a privacy computing system based on TEE and FHE technologies. The system includes a key manager, a data provider, and a computing provider. Specifically:

[0077] The key manager is responsible for generating keys within a trusted area. After key generation, the key manager calls a network sending function in an untrusted area to send the public key to other participants. After obtaining the ciphertext structure uploaded by the computation party, the key manager decrypts the ciphertext result uploaded by the computation party in the trusted area based on the ciphertext result obtained by calling the function, and then calls the network sending function in the untrusted area to send the plaintext result to other data parties. The key includes a private key and a public key, and the other participants include the data party and the computation party. The key manager is determined among the participants in the fully homomorphic encryption environment.

[0078] The data provider is used to obtain plaintext data of the target computing task, encrypt the obtained plaintext data using a public key to obtain ciphertext data, and send the ciphertext data to the computing provider.

[0079] The computational party is used to perform joint computation on the ciphertext data sent by each data party to obtain the ciphertext result of the target computation task, and then send the ciphertext result to the key management party.

[0080] In an optional embodiment of this application, the key manager generates a key within a trusted area, including:

[0081] Generate an FHE private key based on the security parameters and store the private key in a fully homomorphic encrypted environment;

[0082] Generate the corresponding FHE encryption public key using the FHE private key;

[0083] Determine the relinear key required in the FHE private key generation ciphertext calculation process;

[0084] Send the FHE encryption public key and the re-linear key to the other participants.

[0085] In optional embodiments of this application, the key manager may further determine trusted and untrusted regions; wherein the trusted regions include at least an encrypted memory region and an encrypted hardware chip region.

[0086] In optional embodiments of this application, determining the trusted and untrusted regions of the key management party includes determining the trusted region using Intel SGX TEE technology and treating other regions of memory as untrusted regions.

[0087] Specific limitations regarding privacy-preserving computing systems based on TEE and FHE technologies can be found in the above section on limitations of privacy-preserving computing methods based on TEE and FHE technologies, and will not be repeated here. Each module in the aforementioned privacy-preserving computing system based on TEE and FHE technologies can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0088] In one embodiment, an electronic device is provided, which may be a computer, and its internal structure diagram may be as follows: Figure 2As shown, the electronic device includes a processor, memory, and a network interface connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage medium. The database of the computer device is used for privacy-preserving computation data based on TEE and FHE technologies. The network interface of the computer device is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a privacy-preserving computation method based on TEE and FHE technologies.

[0089] Those skilled in the art will understand that, Figure 2 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0090] In one embodiment of this application, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the privacy computing method based on TEE and FHE technologies described above.

[0091] The computer-readable storage medium provided in this embodiment is similar in principle and technical effect to the method embodiment described above, and will not be repeated here.

[0092] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in M ​​forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0093] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A privacy-preserving computation method based on TEE and FHE technologies, characterized in that, The method includes: In a fully homomorphic encryption environment, a key manager is identified among the participants, and a key is generated within a trusted area by the key manager; wherein the key includes a private key and a public key; After the key is generated, the key manager calls a network sending function in an untrusted area to send the public key to other participants; these other participants include data providers and computation providers. The data provider obtains the plaintext data of the target computing task, encrypts the obtained plaintext data using the public key to obtain ciphertext data, and sends the ciphertext data to the computing provider. The computing party performs joint computation on the ciphertext data sent by each data party to obtain the ciphertext result of the target computing task, and sends the ciphertext result to the key management party; In the untrusted area, the key manager obtains the ciphertext result uploaded by the computing party based on the function call, and in the trusted area, decrypts the ciphertext result to obtain the plaintext result of the target computing task. Then, in the untrusted area, the key manager calls the network sending function to send the plaintext result to other data parties. In a fully homomorphic encryption environment, a key manager is identified among the participants, and a key is generated within a trusted area by the key manager, including: Generate an FHE private key based on the security parameters and store the private key in a fully homomorphic encrypted environment; Generate a corresponding FHE encryption public key using the FHE private key; Determine the relinear key required in the FHE private key generation ciphertext calculation process; The FHE encryption public key and the re-linear key are sent to the other participants.

2. The privacy-preserving computation method based on TEE and FHE technologies according to claim 1, characterized in that, In a fully homomorphic encryption environment, a key manager is identified among the participants, and a key is generated within a trusted area by the key manager. The method further includes: The trusted and untrusted areas of the key management party are determined; wherein the trusted areas include at least the encrypted memory area and the encrypted hardware chip area.

3. The privacy-preserving computation method based on TEE and FHE technologies according to claim 2, characterized in that, Determine the trusted and untrusted areas of the key management party, including: Trusted regions are identified using Intel SGX TEE technology, while other regions of memory are designated as untrusted regions.

4. A privacy-preserving computing system based on TEE and FHE technologies, characterized in that, The system includes a key manager, a data provider, and a computation provider, specifically: A key manager is used to generate keys within a trusted area; after key generation, the key manager calls a network sending function to send the public key to other participants in an untrusted area. After obtaining the ciphertext structure uploaded by the computing party, the ciphertext result uploaded by the computing party is obtained from the function call in the untrusted area. The ciphertext result is then decrypted in the trusted area to obtain the plaintext result of the target computing task. The plaintext result is then sent to other data parties by calling the network sending function in the untrusted area. The key includes a private key and a public key. Other participants include the data party and the computing party. The key manager is determined among the participants in the fully homomorphic encryption environment. The data provider is used to obtain plaintext data of the target computing task, encrypt the obtained plaintext data using a public key to obtain ciphertext data, and send the ciphertext data to the computing provider. The computing party is used to perform joint computation on the ciphertext data sent by each data party to obtain the ciphertext result of the target computation task, and then send the ciphertext result to the key management party. The key manager generates keys within a trusted area, including: Generate an FHE private key based on the security parameters and store the private key in a fully homomorphic encrypted environment; Generate a corresponding FHE encryption public key using the FHE private key; Determine the relinear key required in the FHE private key generation ciphertext calculation process; The FHE encryption public key and the re-linear key are sent to the other participants.

5. The privacy computing system based on TEE and FHE technologies according to claim 4, characterized in that, Key management providers also include: Determine trusted and untrusted regions; wherein the trusted regions include at least an encrypted memory region and an encrypted hardware chip region.

6. The privacy computing system based on TEE and FHE technologies according to claim 5, characterized in that, Determine the trusted and untrusted areas of the key management party, including: Trusted regions are identified using Intel SGX TEE technology, while other regions of memory are designated as untrusted regions.

7. An electronic device, characterized in that, It includes a memory and a processor, the memory storing a computer program that, when executed by the processor, implements the privacy computing method based on TEE and FHE technologies as described in any one of claims 1 to 3.

8. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the privacy computing method based on TEE and FHE technologies as described in any one of claims 1 to 3.

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