CN115603907A - Method, device, device and storage medium for encrypting stored data - Google Patents

Abstract

The embodiment of the application discloses a method, device, device and storage medium for encrypting and storing data, which belong to the field of computer technology. The method includes: obtaining initial key material, and obtaining a master key and a corresponding master key identifier; based on a key generation function, processing the initial key material and the master key to obtain a data key ; Based on the data key and encryption algorithm, encrypt the data plaintext to obtain data ciphertext; splice the master key identifier, the initial key material and the data ciphertext to obtain spliced data; The spliced data is stored. By adopting the embodiment of the present application, the waste of storage space can be reduced.

Description

Method, device, device and storage medium for encrypting stored data

technical field

The embodiments of the present application relate to the field of computer technology, and in particular, to a method, device, device, and storage medium for encrypting and storing data.

Background technique

As people pay more and more attention to privacy protection, information security technology has become an important research topic. Information security technology includes information encryption technology and information hiding technology. Among them, information encryption technology converts data plaintext into data ciphertext through an encryption algorithm. Data plaintext refers to some information that needs to be stored, and data ciphertext refers to encrypted information. The encrypted information is garbled and needs to be decrypted to be read. understand.

In some applications, some user information needs to be stored on the server, and before being stored, the information needs to enter the key management system for encryption. The specific process of encryption processing can be: first, the random number generator creates a DK (data key, data key), and inputs the DK and the MK (master key, master key) already stored in the server to the AES (advanced encryption standard , Advanced Encryption Standard), get EDK (encrypted data key, encrypted data key). Then, input DK and data plaintext into AES to obtain data ciphertext. Finally, the data ciphertext and EDK are spliced to obtain the final ciphertext, and the final ciphertext can be stored in the server.

In the related art, the length of EDK is relatively long, and its length is the sum of the length of DK and 28 bytes, resulting in relatively long length of final ciphertext. When a large amount of small data is encrypted and stored, a relatively large storage space will be occupied, resulting in a waste of storage space.

Contents of the invention

Embodiments of the present application provide a method, device, device, and storage medium for encrypting and storing data, which can solve problems in related technologies. The technical solution is as follows:

In a first aspect, a method for encrypting stored data is provided, the method comprising:

Obtain the initial key material, and obtain the master key and the corresponding master key identifier;

processing the initial key material and the master key based on a key generation function to obtain a data key;

Encrypting the data plaintext based on the data key and the encryption algorithm to obtain the data ciphertext;

splicing the master key identifier, the initial key material, and the data ciphertext to obtain spliced data;

The splicing data is stored, and the master key and the data identifier are stored correspondingly.

In a possible implementation manner, the acquiring initial key material includes:

Based on the random number generated by the random number generator, the random number is used as initial key material.

In a possible implementation manner, the acquiring the master key includes:

Obtain the type of the data plaintext;

Based on the corresponding relationship between the type and the master key identifier, obtain the master key identifier corresponding to the type of the data plaintext;

Obtain the master key corresponding to the master key identifier.

In a possible implementation manner, the splicing of the master key identifier, the initial key material, and the data ciphertext to obtain spliced data includes:

splicing the version identifier, the master key identifier, the initial key material, and the data ciphertext to obtain spliced data, wherein the version identifier is used to indicate that the spliced data includes the master key Fields corresponding to the identifier, the initial key material, and the data ciphertext.

In a possible implementation manner, the key generation function is a key derivation function HKDF based on a hashed message authentication code.

In a possible implementation manner, the storing the splicing data includes:

Encoding the spliced data;

Store the encoded string.

In a possible implementation manner, after storing the spliced data, further include:

Splitting the spliced data to obtain the master key identifier, the initial key material, and the data ciphertext;

Obtain the master key based on the master key identifier obtained by splitting;

Based on the key generation function, process the master key and the split initial key material to obtain the data key;

Based on the data key and the decryption algorithm, the data ciphertext obtained by splitting is decrypted to obtain the data plaintext.

In a second aspect, a device for encrypting and storing data is provided, the device comprising:

An acquisition module, configured to acquire initial key material, and acquire a master key and a corresponding master key identifier;

A generation module, configured to process the initial key material and the master key based on a key generation function to obtain a data key;

An encryption module, configured to encrypt data plaintext based on the data key and an encryption algorithm to obtain data ciphertext;

A splicing module, configured to splice the master key identifier, the initial key material, and the data ciphertext to obtain spliced data;

A storage module, configured to store the splicing data.

In a possible implementation manner, the obtaining module is configured to:

Based on the random number generated by the random number generator, the random number is used as initial key material.

In a possible implementation manner, the obtaining module is configured to:

Obtain the type of the data plaintext;

Based on the corresponding relationship between the type and the master key identifier, obtain the master key identifier corresponding to the type of the data plaintext;

Obtain the master key corresponding to the master key identifier.

In a possible implementation manner, the splicing module is also used for:

splicing the version identifier, the master key identifier, the initial key material, and the data ciphertext to obtain spliced data, wherein the version identifier is used to indicate that the spliced data includes the master key Fields corresponding to the identifier, the initial key material, and the data ciphertext.

In a possible implementation manner, the key generation function is a key derivation function HKDF based on a hashed message authentication code.

In a possible implementation manner, the storage module is configured to:

Encoding the spliced data;

Store the encoded string.

In a possible implementation manner, the device further includes:

Decryption module for:

Splitting the spliced data to obtain the master key identifier, the initial key material, and the data ciphertext;

Obtain the master key based on the master key identifier obtained by splitting;

Based on the key generation function, process the master key and the split initial key material to obtain the data key;

Based on the data key and the decryption algorithm, the data ciphertext obtained by splitting is decrypted to obtain the data plaintext.

A third aspect provides a computer device, the computer device includes a memory and a processor, the memory is used to store computer instructions; the processor executes the computer instructions stored in the memory, so that the computer device executes the first aspect and possible implementations thereof method.

In a fourth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores computer program codes. In response to the computer program code being executed by a computer device, the computer device executes the method of the first aspect and possible implementations thereof.

In a fifth aspect, a computer program product is provided, the computer program product includes computer program code, and in response to the computer program code being executed by a computer device, the computer device executes the method of the first aspect and possible implementations thereof.

The technical solutions provided by the embodiments of the present application may include the following beneficial effects:

Through the method provided in the embodiment of this application, firstly, the initial key material, the master key and the master key identifier are acquired. Then, the initial key material and the master key are used as the input of the key generation function to calculate the data key. Then use the data key and encryption algorithm to encrypt the data plaintext to obtain the data ciphertext. Finally, the master key identifier corresponding to the data plaintext, the initial key material and the data ciphertext are spliced to obtain spliced data. Store the spliced data. Because the length of the initial key material used by the general key generation function can be set arbitrarily, the length of the initial key material can be set to a smaller value, so that the occupied storage space is smaller and can be reduced Waste of storage space.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

FIG. 1 is a schematic structural diagram of a service server provided by an embodiment of the present application;

FIG. 2 is a schematic flow diagram of a method for encrypting and storing data provided in an embodiment of the present application;

Fig. 3 is a schematic diagram of the structure of a data ciphertext provided by the embodiment of the present application;

Fig. 4 is a schematic diagram of a structure of splicing data provided by an embodiment of the present application;

FIG. 5 is a schematic flow diagram of a method for decrypting data provided in an embodiment of the present application;

Fig. 6 is a schematic structural diagram of a device for encrypting and storing data provided by an embodiment of the present application.

detailed description

The embodiment of the present application provides a method for encrypting and storing data, which can be applied to a service server, and the service server can be a single server or a device group composed of multiple devices.

In terms of hardware composition, the structure of the service server may be as shown in FIG. 1 , including a processor 110 , a memory 120 and a communication component 130 .

The processor 110 may be a CPU (central processing unit, central processing unit) or a SoC (system on chip, system-on-chip), and the processor 110 may be configured to execute various instructions involved in the method, and the like.

The memory 120 may include various volatile memories or nonvolatile memories, such as SSD (solid state disk, solid state disk), DRAM (dynamic random access memory, dynamic random access memory) memory, and the like. The memory 120 may be used to store pre-stored data, intermediate data, and result data during the encryption process, for example, data ciphertext, concatenated data, and the like.

The communication component 130 may be a wired network connector, a WiFi (wireless fidelity, wireless fidelity) module, a Bluetooth module, a cellular network communication module, and the like. The communication component may be used for data transmission with other devices, and the other devices may be servers or other terminals.

Below, several nouns involved in the embodiments of this application are introduced:

MK (master key, master key): It is a key used directly or indirectly for data encryption. In this embodiment of the application, the master key is indirectly used for data encryption.

DK (data key, data key): It is a key directly used for data encryption. In the embodiment of this application, DK is generated by processing MK and other data by a key generation function.

HKDF (hash-based message authentication code-based extract-and-expandkey derivation function, key derivation function based on hash message authentication code): A function used to calculate a data key based on some key material.

IKM (initial key material, initial key material): It is one of the input data when using HKDF to generate the data key. As the name implies, it is the raw material used to generate the data key. In this embodiment of the application, the initial key material and the master key are jointly used to generate a data key.

AES (advanced encryption Standard, Advanced Encryption Standard): It is a symmetric data key algorithm, that is, encryption and decryption use the same data key. When encrypting, AES_GCM_encrypt (an encryption algorithm) can be used to encrypt data plaintext into data ciphertext; when decrypting, AES_GCM_decrypt (a decryption algorithm) can be used to decrypt data ciphertext into data plaintext. Among them, GCM (Galois counter mode, Galois counter mode) is an encryption mode of symmetric encryption, with GMAC (Galois message authentication code mode, Galois message authentication code), which can perform integrity verification on data ciphertext test.

KMS (key management service, key management service): It is a software or a combination of software and hardware that provides one-stop key management and data plaintext encryption services, providing simple, reliable, safe, and compliant data plaintext encryption protection capabilities. KMS can be built on an independent server, or installed in the form of software on a device for data storage.

In some cases, the business server will perform some business processing based on the terminal's request, or may independently trigger some business processing based on the local processing logic. During the business processing, business data may be generated and need to be encrypted for storage.

For this application scenario, the embodiment of the present application provides a method for encrypting and storing data. The processing flow of this method can be shown in Figure 2, including the following processing steps:

201. Acquire initial key material, and acquire a master key and a corresponding master key identifier.

Wherein, the initial key material can be a random number, which is generated by a random number generator, and its length can be set as required. For example, the initial key material may be a 16-byte random number.

The master key is pre-generated based on certain rules and stored in KMS. The length of the master key can be set as required. The length of the master key is positively related to the security of data encryption, so the length of the master key can be set to be greater than a certain length threshold, such as 100 bytes.

In implementation, after the user completes a certain service in the application program on the terminal, the terminal sends a message of completing the service to the service server. The message may carry business data. For example, when the business of modifying the account profile picture is completed, the terminal sends the service data to the server as a picture of the profile picture. Business data is the data that needs to be encrypted and stored later, so it can also be called data plaintext. After receiving this message, the business server obtains the initial key material, the master key, and the master key identifier corresponding to the master key.

The way to obtain the initial key material may be that after receiving the data plaintext, the service server invokes a random number generator to generate a random number. Alternatively, store some random numbers in advance in the service server, and randomly select a random number as the initial key material after receiving the data plaintext.

The manner of obtaining the master key identifier may be to determine the master key identifier based on the type of the data plaintext. A correspondence table (as shown in Table 1) between the type of data plaintext and the identification of the master key is pre-established on the service server. After receiving the data plaintext, the service server determines the type of the data plaintext, and searches for the corresponding master key identifier in the above correspondence table.

Table 1

Type of data plaintext master key ID avatar 0001 Nick name 0002 sign 0003 account level 0004 ... ...

For example, when the user completes the service of modifying the nickname on the terminal, the terminal sends the service data to the server, which is the nickname set by the user. After receiving the service data, the service server checks the table to determine that the master key identifier corresponding to the type of nickname is 0002.

The way to obtain the master key may be to firstly carry out preparatory work, when generating the master key, assign a corresponding master key identifier to each master key, and store the master key and the master key identifier correspondingly. When the data plaintext needs to be encrypted and stored, after the master key identifier is determined, a table lookup is performed based on the master key identifier to determine the corresponding master key.

202. Based on the key generation function, process the initial key material and the master key to obtain a data key.

Among them, the key generation function is HKDF, which includes two modules, namely an extraction module and an extension module.

In the implementation, the master key is set as Salt (salt value), and the Salt and initial key material are input into the extraction module of HKDF, and the extraction module obtains PRK (pseudo random key, pseudo-random key) through calculation. Input PRK, info, and L into the extension module, and the extension module obtains the data key through calculation. Among them, info is the master key identifier, L is the length of the output data key, and L can be manually set and stored.

With HKDF, a data key of a specific length can be generated by setting L. For the extraction module and extension module of HKDF, when the input parameters (Salt, initial key material, info, L) are the same, the output data key is the same. Since the data key is used to encrypt data plaintext, in order to ensure the security of the encryption, the data key is generally not stored in the server. When using the data key, use the acquired initial key material and master key to generate the data key in real time through HKDF.

203. Encrypt the plaintext of the data based on the data key and the encryption algorithm to obtain the ciphertext of the data.

Wherein, the encryption algorithm may be AES_GCM_encrypt.

In implementation, the data key and the data plaintext are input into AES_GCM_encrypt, and after AES_GCM_encrypt uses the data key to encrypt the data plaintext, the data ciphertext is output, that is, the data ciphertext=AES_GCM_encrypt(X, DK), where X is the data clear text. The data ciphertext encrypted by AES_GCM_encrypt can be composed of three parts, including IV (initialization vector, initial vector), ciphertext and GMAC, wherein the lengths of IV and GMAC are fixed, 12 bytes and 16 bytes respectively.

The master key identifier is determined by the type of data plaintext. For the same data plaintext type, the master key identifier is the same, that is, the master key used when generating the data key is the same. In some cases, when the same data plaintext may be encrypted multiple times, if the data key is the same, the generated data ciphertext is also the same. Therefore, in order to ensure security, an interference item, ie IV, can be added to obtain different data ciphertexts. GMAC is a piece of information generated after a specific algorithm. The specific algorithm can be AES_GCM_encrypt. GMAC is used to check whether the content of the message has been changed during the delivery process.

The structure of the data ciphertext obtained after encryption is shown in FIG. 3 . The length of the data ciphertext is the sum of 28 bytes and the length of the ciphertext, and the length of the ciphertext is the same as the data plaintext.

204. Concatenate the master key identifier, initial key material, and data ciphertext to obtain concatenated data.

Wherein, the length of the master key identifier is fixed.

In implementation, the splicing sequence of master key identifier, initial key material, and data ciphertext may be: master key identifier, initial key material, data ciphertext, or initial key material, master key identifier, Data ciphertext, or, master key identifier, data ciphertext, initial key material, etc. It is also possible to concatenate the initial key material and data ciphertext.

In this way, the length of the initial key material is set arbitrarily, and the initial key material is used as a part of the concatenated data. On the premise of ensuring encryption security, the length of the concatenated data can be reduced and the waste of storage space can be reduced.

As shown in Figure 4, the length of the master key identifier is A bytes, the length of the initial key material is B bytes, and the length of the data plaintext is C bytes. The length of the data ciphertext obtained after AES_GCM_encrypt encrypts the data plaintext is the sum of 28 bytes and C bytes. The length of the concatenated data obtained by concatenating the master key identifier, the initial key material and the data ciphertext is (A+B+C+28) bytes.

In step 204, the first version identification, master key identification, initial key material and data ciphertext may also be concatenated to obtain concatenated data.

Wherein, the first version identifier is used to indicate that the concatenated data includes fields corresponding to the master key identifier, initial key material, and data ciphertext. The length of the first version identifier may be one byte. Based on some other requirements, other settings can also be made to the fields of the spliced data, and other version identifiers can be used accordingly. For example, the second version identifier can be concatenated with some specified data to obtain spliced data, and the second version identifier is used to indicate that the spliced data includes these specified data.

205. Store the spliced data.

In implementation, the spliced data may be encoded by using Base64 (a codec algorithm), and the encoded character strings may be stored.

Corresponding to the above-mentioned processing steps of encrypting and storing plaintext data, the decryption processing steps may be:

501. Split the concatenated data to obtain a master key identifier, initial key material, and data ciphertext.

In implementation, in some business processes, the terminal will send a read request to the business server. Wherein, the read request may carry the data identifier of the data to be read in plaintext. The service server can obtain the data identifier carried in the read request, and determine the character string of the spliced data corresponding to the data identifier among the strings corresponding to all the spliced data stored in it. The string is decoded by Base64 to obtain the corresponding spliced data. Then, split the spliced data.

When splitting the spliced data, the spliced data can be split according to the pre-recorded composition of the spliced data and the length of each component.

For example, the components of the concatenated data are three parts: the master key identifier, the initial key material, and the data ciphertext, in which the length of the master key identifier is X bytes, the length of the initial key material is Y bytes, and the data The ciphertext is Z bytes. In the spliced data, the Xth byte starting from the first byte, the position between the Xth byte and the X+1th byte can be determined, and the spliced data is split to obtain the data of the first X bytes (which can be called as the first data segment) and other data (may be referred to as the second data segment). Identify the first X bytes of data as the master key identifier. Then, determine the Yth byte starting from the first byte in the second data segment, and the position between the Yth byte and the Y+1 byte, and split the spliced data to obtain the data of the first Y bytes. The first Y bytes of data are determined as the initial key material, and the remaining part is the data ciphertext. Alternatively, the Xth byte from the first byte can be determined in the spliced data, the position between the Xth byte and the X+1th byte can be marked, and then continue to determine the X+Yth byte from the first byte, The position between the X+Yth byte and the X+Y+1 byte is marked. Then, split the marked position to obtain the master key identifier, initial key material, and data ciphertext.

In the case that the spliced data also includes a version identifier, splitting may also be performed at the positions of the first byte and the second byte of the spliced data to obtain the first version identifier and the rest. Determine the components of the remaining part of the spliced data according to the first version identifier obtained by splitting, and the length of each component of the remaining part, and split the remaining part of the spliced data according to the above splitting method, which will not be repeated here repeat.

502. Acquire a master key based on the master key identifier obtained through splitting.

In implementation, the service server can obtain the master key identifier obtained by splitting the spliced data. Based on the master key identifier, the KMS searches for the corresponding master key from the above-mentioned correspondence between the master key and the master key identifier.

Optionally, in another processing manner, the type of plaintext data to be read may be carried in the read request. The business server can use this type to search for the corresponding master key identifier in the above-mentioned correspondence table between the data plaintext type and the master key identifier. The KMS searches for the corresponding master key from the correspondence table between the master key identifier and the master key.

503. Based on the key generation function, process the master key and the split initial key material to obtain a data key.

In the implementation, the master key and the split initial key material are input into the extraction module of HKDF, and the output is PRK. Input PRK, master key identifier, and L into the extension module, and output the data key.

504. Based on the data key and the decryption algorithm, decrypt the data ciphertext to obtain the data plaintext.

Wherein, the decryption algorithm may be AES_GCM_decrypt.

In implementation, the input data key and data ciphertext are input into AES_GCM_decrypt, and after AES_GCM_decrypt uses the data key to decrypt the data ciphertext, the data plaintext is output, that is, data plaintext=AES_GCM_decrypt(X, DK), where X is the data ciphertext. The business server sends the decrypted plaintext data to the terminal, or performs subsequent business processing locally based on the plaintext data.

Through the method provided in the embodiment of this application, firstly, the initial key material, the master key and the master key identifier are obtained. Then, the initial key material and the master key are used as the input of the key generation function to calculate the data key. Then use the data key and encryption algorithm to encrypt the data plaintext to obtain the data ciphertext. Finally, the master key identifier, initial key material and data ciphertext are concatenated to obtain concatenated data. Store the spliced data. Because the length of the initial key material used by the general key generation function can be set arbitrarily, the length of the initial key material can be set to a smaller value, so that the occupied storage space is smaller and can be reduced Waste of storage space.

Based on the same technical concept, the embodiment of the present application also provides a device for encrypting and storing data, as shown in Figure 6, the device includes:

An acquisition module 610, configured to acquire initial key material, and acquire a master key and a corresponding master key identifier;

A generation module 620, configured to process the initial key material and the master key based on a key generation function to obtain a data key;

An encryption module 630, configured to encrypt data plaintext based on the data key and an encryption algorithm to obtain data ciphertext;

A splicing module 640, configured to splice the master key identifier, the initial key material, and the data ciphertext to obtain spliced data;

The storage module 650 is configured to store the splicing data.

In a possible implementation manner, the obtaining module 610 is configured to:

Based on the random number generated by the random number generator, the random number is used as initial key material.

In a possible implementation manner, the obtaining module 610 is configured to:

Obtain the type of the data plaintext;

Based on the corresponding relationship between the type and the master key identifier, obtain the master key identifier corresponding to the type of the data plaintext;

Obtain the master key corresponding to the master key identifier.

In a possible implementation manner, the splicing module is also used for:

splicing the version identifier, the master key identifier, the initial key material, and the data ciphertext to obtain spliced data, wherein the version identifier is used to indicate that the spliced data includes the master key Fields corresponding to the identifier, the initial key material, and the data ciphertext.

In a possible implementation manner, the key generation function is a key derivation function HKDF based on a hashed message authentication code.

In a possible implementation manner, the storage module 650 is configured to:

Encoding the spliced data;

Store the encoded string.

In a possible implementation manner, the device further includes:

Decryption module for:

Splitting the spliced data to obtain the master key identifier, the initial key material, and the data ciphertext;

Obtain the master key based on the master key identifier obtained by splitting;

Based on the key generation function, process the master key and the split initial key material to obtain the data key;

Based on the data key and the decryption algorithm, the data ciphertext obtained by splitting is decrypted to obtain the data plaintext.

Through the device provided by the embodiment of this application, firstly, the initial key material, the master key and the master key identifier are obtained. Then, the initial key material and the master key are used as the input of the key generation function to calculate the data key. Then use the data key and encryption algorithm to encrypt the data plaintext to obtain the data ciphertext. Finally, the master key identifier, initial key material and data ciphertext are concatenated to obtain concatenated data. Store the spliced data. Because the length of the initial key material used by the general key generation function can be set arbitrarily, the length of the initial key material can be set to a smaller value, so that the occupied storage space is smaller and can be reduced Waste of storage space.

It should be noted that: when the device for encrypting and storing data provided by the above-mentioned embodiments encrypts and stores data, it only uses the division of the above-mentioned functional modules as an example for illustration. In practical applications, the above-mentioned functions can be allocated by different functions Module completion means that the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the device for encrypting and storing data provided by the above embodiments and the method for encrypting and storing data belong to the same idea, and the specific implementation process thereof is detailed in the method embodiment, and will not be repeated here.

In the embodiment of the present application, there is also provided a computer-readable storage medium, such as a memory including instructions, and the above instructions can be executed by a processor in the terminal to complete the method for performing interactive operations in the above embodiments. The computer readable storage medium may be non-transitory. For example, the computer-readable storage medium may be ROM (Read-Only Memory, read only memory), RAM (Random Access Memory, random access memory), CD-ROM, magnetic tape, floppy disk, and optical data storage device, etc.

It should be noted that the information involved in this application (including but not limited to user equipment information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals ( Including but not limited to signals transmitted between the user terminal and other devices, etc.), are authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws and regulations of the relevant countries and regions and standard.

Those of ordinary skill in the art can understand that all or part of the steps for implementing the above embodiments can be completed by hardware, and can also be completed by instructing related hardware through a program. The program can be stored in a computer-readable storage medium. The above-mentioned The storage medium mentioned may be a read-only memory, a magnetic disk or an optical disk, and the like.

The above descriptions are only some possible embodiments of the application, and are not intended to limit the application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the application shall be included in the scope of the application. within the scope of protection.

Claims (10)

1. A method of encrypting stored data, the method comprising:

acquiring initial key material, and acquiring a master key and a corresponding master key identifier;

processing the initial key material and the master key based on a key generation function to obtain a data key;

encrypting a data plaintext based on the data key and an encryption algorithm to obtain a data ciphertext;

splicing the master key identification, the initial key material and the data ciphertext to obtain spliced data;

and storing the spliced data.

2. The method of claim 1, wherein obtaining initial keying material comprises:

the random number is used as initial key material based on the random number generated by the random number generator.

3. The method of claim 1, wherein obtaining the master key and the corresponding master key identifier comprises:

acquiring the type of the data plaintext;

acquiring a master key identifier corresponding to the type of the data plaintext based on the corresponding relationship between the type and the master key identifier;

and acquiring a master key corresponding to the master key identification.

4. The method according to claim 1, wherein the concatenating the master key identifier, the initial key material, and the data ciphertext to obtain concatenated data comprises:

and splicing the version identifier, the master key identifier, the initial key material and the data ciphertext to obtain spliced data, wherein the version identifier is used for indicating fields corresponding to the master key identifier, the initial key material and the data ciphertext in the spliced data.

5. The method of claim 1, wherein the key generation function is a key derivation function HKDF based on a hashed message authentication code.

6. The method of claim 1, wherein storing the splice data comprises:

encoding the spliced data;

and storing the character string obtained by encoding.

7. The method according to any one of claims 1 to 6, wherein after storing the splicing data, further comprising:

splitting the spliced data to obtain the master key identification, the initial key material and the data ciphertext;

acquiring the master key based on the master key identification obtained by splitting;

processing the master key and the initial key material obtained by splitting based on the key generation function to obtain the data key;

and decrypting the data ciphertext obtained by splitting based on the data key and a decryption algorithm to obtain the data plaintext.

8. An apparatus for encrypting stored data, the apparatus comprising:

the acquisition module is used for acquiring initial key materials and acquiring a master key and a corresponding master key identifier;

a generating module, configured to process the initial key material and the master key based on a key generation function to obtain a data key;

the encryption module is used for encrypting a data plaintext based on the data secret key and an encryption algorithm to obtain a data ciphertext;

the splicing module is used for splicing the master key identification, the initial key material and the data ciphertext to obtain spliced data;

and the storage module is used for storing the spliced data.

9. A computer device, comprising a memory for storing computer instructions and a processor;

the processor executes the computer instructions stored by the memory to cause the computer device to perform the method of any of claims 1 to 7.

10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores computer program code which, in response to execution of the computer program code by a computer device, executes the method of any of the preceding claims 1 to 7.

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