WO2017000726A1 - Key transformation method, apparatus, and terminal - Google Patents

Abstract

The present invention relates to the communications field, and disclosed are a key transformation method, apparatus, and terminal. The method comprises: obtaining a target matrix in a matrix library, the target matrix being an invertible matrix; transforming, after using an initial key to encrypt a target file, the initial key according to the target matrix, and generating a protection key; and storing the protection key and a key recovery file of the protection key to a dynamic-library file, the protection key being capable of recovering to the initial key through inverse transformation by using the key recovery file. According to embodiments of the present invention, an initial key is transformed, so that a plain-text encryption key cannot be obtained without permission. Therefore, a target file cannot be encrypted, so that the security performance is improved.

Description

Key conversion method, device and terminal Technical field

This paper relates to the field of communications, and in particular to a key conversion method, apparatus and terminal.

Background technique

As an emerging operating system, Android Android has been supported by many developers and many vendors. The number of applications based on the Android platform has also increased rapidly. However, the research on software protection technology under the Android platform is still in its infancy, and the open source of the code makes it easy for developers to be infected with malicious attackers. The Android system provides more functional interfaces for application developers. Many of the system's low-level interfaces improve the scalability of the system, but also provide convenience for malware. Trojans such as Trojans for Android are also easier to be. Implementation, the existing malware for Android system can spoof the user installation and grant certain permissions by disguising, and then abuse these permissions to perform certain behaviors in the background, including stealing user privacy and defrauding fees. However, the security problems that have been born with it have not been solved well, security threats are increasing, and the threat level is gradually deepening, which has a negative impact on both developers and users.

Based on this consideration, Android software needs to be protected. Software hardening is proposed from the perspective of a third party to implement code reinforcement for any application, which requires the versatility of the reinforcement system. The hardening process can be completed without obtaining the application code, and the security of the application can be increased to a certain extent to prevent threats from malicious attackers, including: illegal copying and unauthorized use, ie piracy: malicious modification of the software code Logic or function, that is, tampering; obtaining core algorithms and key data through reverse engineering and porting them to their own software, ie reverse engineering.

The traditional Android software protection method is to shell the APK installation package file. The existing shelling method generally hides the DEX executable file after it is encrypted. In this process, the key for encrypting the DEX file is generally stored in the memory or written in plaintext. Once the attacker obtains it, it will be able to decrypt the DEX file and crack the original program.

Summary of the invention

The following is a summary of the subject matter described in detail herein, and is not intended to limit the scope of the claims.

Disclosed herein is a key conversion method, apparatus, and terminal, which converts an encryption key and stores it in a file, thereby realizing a scheme in which an encryption key of a plaintext cannot be obtained without permission.

To achieve the above object, the present invention discloses a key conversion method, the method comprising:

Obtaining a target matrix in the matrix library, the target matrix being an invertible matrix;

After the target file is encrypted by using the initial key, the initial key is transformed according to the target matrix to generate a protection key;

And storing the protection key and the key recovery file of the protection key into a dynamic library file; wherein the protection key can be restored to an initial key by inverse transformation of the key recovery file.

Optionally, wherein the step of constructing the matrix library comprises:

Obtaining all the matrices satisfying the first rule, and obtaining a matrix set, where the first rule is a binary matrix whose matrix is N×N, where N is an integer greater than or equal to 2;

Obtaining a preset number of all matrices satisfying the second rule in the matrix set to obtain a matrix library, and the second rule is that the matrix is an invertible matrix.

Optionally, the transforming the initial key according to the target matrix to generate a protection key includes:

Multiplying the initial key by the target matrix, and the obtained operation result is a protection key; or

Generating a conversion table according to the target matrix, searching a transformation result of the initial key in the transformation table, and using the transformation result as a protection key.

Optionally, the generating, according to the target matrix, a transformation table, comprising:

Setting first input data and second input data;

Multiplying the combined data of the first input data and the second input data by the target matrix to obtain all output results;

A conversion table is generated based on the values of the first input data and the second input data and the output result.

Optionally, the generating, according to the target matrix, a transformation table, comprising:

Setting first input data and second input data;

When the first input data is 0, the combined data of the first input data and the second input data is multiplied by the first output result obtained by the target matrix;

When the second input data is 0, the combined data of the first input data and the second input data is multiplied by the second output result obtained by the target matrix;

A conversion table is generated based on the values of the first input data and the second input data and the first output result and the second output result.

Optionally, wherein the first input data and the second input data are hexadecimal numbers.

Optionally, wherein the searching for the transformation result of the initial key in the transformation table includes:

And converting, according to the data form of the first input data and the second input data, the initial key into a data form to obtain a transformed initial key;

Finding a corresponding transform result in the conversion table according to the transform initial key.

The key recovery file is the target matrix, an inverse matrix of the target matrix, or a conversion table corresponding to the target matrix.

To achieve the above object, a key conversion method is also disclosed herein, the method comprising:

Obtain the key recovery file and protection key saved in the dynamic library file;

The protection key is inversely transformed according to the key recovery file to obtain an initial key.

The key recovery file is the target matrix, an inverse matrix of the target matrix, or a conversion table corresponding to the target matrix;

Optionally, the inverse transforming the protection key according to the key recovery file to obtain an initial key includes:

Multiplying the protection key by an inverse matrix of the target matrix, and the obtained operation result is an initial key; or

The first input data and the second input data corresponding to the protection key are searched in the conversion table, and all the first input data and the second input data obtained are initial keys.

In order to achieve the above object, a key conversion device is also disclosed herein, the device comprising:

a first acquiring module, configured to acquire a target matrix in the matrix library, where the target matrix is an invertible matrix;

a protection key generation module, configured to: after encrypting the target file by using the initial key, transform the initial key according to the target matrix to generate a protection key;

a storage module, configured to save the protection key and the key recovery file of the protection key And stored in the dynamic library file; wherein the protection key can be restored to the initial key by the key recovery file inverse transformation.

Optionally, the device further includes:

a second acquiring module, configured to acquire all matrices satisfying the first rule, to obtain a matrix set, where the first rule is a binary matrix whose matrix is N×N, where N is an integer greater than or equal to 2;

The third obtaining module is configured to obtain a preset number of all matrices satisfying the second rule in the matrix set to obtain a matrix library, where the second rule is that the matrix is a reversible matrix.

Optionally, the protection key generation module includes:

a first protection key generation submodule, configured to multiply the initial key by the target matrix, and obtain an operation result as a protection key;

The second protection key generation submodule is configured to generate a conversion table according to the target matrix, search for a transformation result of the initial key in the transformation table, and use the transformation result as a protection key.

Optionally, the second protection key generation submodule includes:

a first setting unit configured to set the first input data and the second input data;

An arithmetic unit configured to multiply the combined data of the first input data and the second input data by the target matrix to obtain all output results;

The first conversion table generating unit is configured to generate a conversion table based on the values of the first input data and the second input data and the output result.

Optionally, the second protection key generation submodule includes:

a second setting unit configured to set the first input data and the second input data;

a first obtaining unit, configured to acquire, when the first input data is 0, a combination of the first input data and the second input data by a first output result obtained by multiplying the target matrix;

a second obtaining unit, configured to acquire, when the second input data is 0, the combined data of the first input data and the second input data is multiplied by the second output result obtained by the target matrix;

The second conversion table generating unit is configured to generate a conversion table according to the values of the first input data and the second input data and the first output result and the second output result.

The first input data and the second input data are hexadecimal numbers.

Optionally, the second protection key generation submodule includes:

a data form transformation unit configured to be based on the number of the first input data and the second input data According to the form, the initial key is transformed into a data form to obtain a transformed initial key;

The searching unit is configured to search for a corresponding transformation result in the transformation table according to the transformation initial key.

The key recovery file is the target matrix, an inverse matrix of the target matrix, or a corresponding conversion table of the target matrix.

In order to achieve the above object, a key conversion device is also disclosed, wherein the device includes:

a second obtaining module, configured to obtain a key recovery file and a protection key stored in the dynamic library file;

The protection key inverse transform module is configured to inverse transform the protection key according to the key recovery file to obtain an initial key.

The key recovery file is the target matrix, an inverse matrix of the target matrix, or a corresponding conversion table of the target matrix;

Optionally, the protection key inverse transform module includes:

a first initial key inverse transform submodule, configured to multiply the protection key by an inverse matrix of the target matrix, and obtain an operation result as an initial key;

a second initial key inverse transform submodule configured to search for the first input data and the second input data corresponding to the protection key in the conversion table, and obtain all initial input data and second input data as initial Key.

To achieve the above object, a terminal is also disclosed herein, including a key conversion device as described above.

To achieve the above object, a terminal is also disclosed herein, including a key conversion device as described above.

The beneficial effects of the above technical solution of the present invention are as follows:

In the key conversion method of the embodiment of the present invention, after obtaining an invertible matrix as a target matrix in the matrix library, the initial key for encrypting the target file is transformed according to the target matrix to generate a protection key, and the protection key is obtained. The key and its key recovery file are stored in a dynamic file library. In this way, after the installation package is packaged, when the application terminal runs the installation package, the protection key can be reverse transformed to the initial key by using the key recovery file in the dynamic file, and then the target file is decrypted using the initial key. The transformation of the initial key makes it impossible to obtain the plaintext encryption key without permission, so that the solution cannot be solved. Confidential object files for improved security.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a flow chart showing the steps of a key conversion method for initial key conversion according to an embodiment of the present invention;

2 is a first flowchart of a specific step of generating a conversion table in a key conversion method according to an embodiment of the present invention;

3 is a second flowchart of a specific step of generating a conversion table in a key conversion method according to an embodiment of the present invention;

4 is a flow chart showing the steps of a key conversion method for inverse transform of a protection key according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a key conversion apparatus for initial key conversion according to an embodiment of the present invention; FIG.

FIG. 6 is a schematic structural diagram of a key conversion apparatus for inverse transform of a protection key according to an embodiment of the present invention.

Preferred embodiment of the invention

The technical problems, the technical solutions, and the advantages of the present invention will be more clearly described in the following description.

After encrypting the DEX file with the encryption key for the existing software protection, the encryption key is stored in the memory or written in the plaintext file, which is easy for the attacker to obtain the problem of decrypting the DEX file, cracking the original program, and having low security. This paper discloses a key conversion method, which converts an encryption key and stores it in a file, thereby realizing a scheme in which an encryption key of a plaintext cannot be obtained without permission.

Embodiment 1

As shown in FIG. 1, a key conversion method includes:

Step 11: Obtain a target matrix in the matrix library, where the target matrix is an invertible matrix;

Step 12: After encrypting the target file by using the initial key, transform the initial key according to the target matrix to generate a protection key.

Step 13: Store the protection key and the key recovery file of the protection key into a dynamic library file; wherein the protection key can be restored to an initial key by the key recovery file inverse transformation.

The key transformation method of the embodiment of the present invention acquires an invertible matrix as a target in the matrix library. After the matrix, the initial key for encrypting the target file is transformed according to the target matrix to generate a protection key, and the protection key and its key recovery file are stored in the dynamic file library. In this way, after the installation package is packaged, when the application terminal runs the installation package, the protection key can be reverse transformed to the initial key through the key recovery file in the dynamic file library, and the target file is decrypted using the initial key. The scheme of transforming the initial key is adopted, so that the plaintext encryption key cannot be obtained without permission, so that the target file cannot be decrypted, and the security performance is improved.

Optionally, the step of constructing the matrix library includes:

Step 14: Obtain all matrices satisfying the first rule, and obtain a matrix set. The first rule is a binary matrix whose matrix is N×N, where N is an integer greater than or equal to 2;

Step 15: Obtain a preset number of all matrices satisfying the second rule in the matrix set to obtain a matrix library, where the second rule is that the matrix is an invertible matrix.

Since the commonly used initial key is 128 bits, in order to facilitate the transform operation, when constructing the matrix library, first obtain all N×N binary matrices to obtain a matrix set as the candidate matrix, and N is an integer greater than or equal to 2. However, due to the nature of the use of the key, it is also necessary to quickly recover after the transformation. Therefore, the reversible matrix in the matrix set is again selected, and in order to ensure that the target matrix can have a large randomness, the reversible matrix of the constructed matrix library is selected. The number must reach the preset number, which can be set by the staff.

Optionally, step 12 includes:

Step 121a, multiplying the initial key by the target matrix, and obtaining an operation result as a protection key; or

Step 121b: Generate a conversion table according to the target matrix, search for a transformation result of the initial key in the transformation table, and use the transformation result as a protection key.

After the target matrix is obtained, the initial key can be transformed. The target matrix can be directly used, and the target matrix is multiplied by the initial key, and the obtained result is the protection key. For the binary operation, the multiplication is the AND operation. If the target matrix is an M matrix,

The 128-bit initial key is divided into a plurality of 8-bit data, and each 8-bit data is sequentially multiplied by the matrix M to obtain a transformed result.

A transformation table may also be generated according to the target matrix line, and the transformation result of the initial key is found by means of a lookup table to obtain a final protection key.

As shown in FIG. 2, in step 121b, a method 1 for generating a conversion table according to the target matrix includes:

Step 121b1a, setting first input data and second input data;

Step 121b2a, multiplying the combined data of the first input data and the second input data by the target matrix to obtain all output results;

Step 121b3a generates a conversion table based on the values of the first input data and the second input data and the output result.

The above steps are the generation method of the conversion table. First, two input data, a first input data and a second input data are set, and each combination of the two data is multiplied by the target matrix to obtain all the output results, and then A conversion table is finally generated according to the values of the first input data and the second input data and the output result.

The first input data and the second input data are hexadecimal numbers.

For example, if the first input data is X, the second input data is Y, X and Y are in the range of 0 to f, and the combined data XY is multiplied by the selected target matrix, and all the output results are obtained, and a conversion table is generated. As follows:

Due to the particularity of the operation, it should also be understood that the result of the operation of multiplying the combined data of the first input data X and the second input data Y by the target matrix is equal to the output result of the input combined data being 0Y (0 means X is 0) and The output result of X0 (0 means Y is 0) is different or different. Therefore, as shown in FIG. 3, in step 121b, a method 2 of generating a conversion table according to the target matrix includes:

Step 121b1b, setting first input data and second input data;

Step 121b2b, when the first input data is 0, the combined output data of the first input data and the second input data is multiplied by the target matrix to obtain a first output result;

Step 121b3b, when the second input data is 0, the combined data of the first input data and the second input data is multiplied by the second output result obtained by the target matrix;

Step 121b4b, generating a conversion table according to the values of the first input data and the second input data and the first output result and the second output result.

In the second generation method of the above-described conversion table, only the first row and the first column of the output result in the conversion table shown in the above table are acquired by the generation method of the steps 121b1b to 121b4b.

Regardless of the specific implementation of the conversion table, after the transformation table is generated, the transformation of the initial key to the protection key may be performed. In step 121b, the transformation result of the initial key is searched in the transformation table, including:

Steps 121b4a/121b5b, according to the data form of the first input data and the second input data, transform the initial key into a data form to obtain a transformed initial key;

Step 121b5a/121b6b searches for a corresponding transformation result in the conversion table according to the transformation initial key.

For the implementation form of the above two conversion tables, when searching for a table, first according to the first input data And the data form of the second input data is used to transform the initial password to facilitate direct searching. The first input data and the second input data are hexadecimal numbers, for example, a set of 8-bit 01101010 data conversion of the binary initial password. If the hexadecimal number is 6A, then in the lookup table, find the first input data as 6, the second input data is the output result corresponding to A, and then find all the corresponding output results of the initial password in the same way. When you come out, you get the result of the transformation, which is the protection key. For the conversion table generated by the second method, if the transformation initial key is determined, if it cannot be directly found in the table, the corresponding 0Y output result and the X0 output result need to be searched first, and then the difference is performed. Or the result is the result of the transformation, that is, the protection key.

Since the manner of transforming the initial key is different, the key recovery file is the target matrix, an inverse matrix of the target matrix, or a corresponding conversion table of the target matrix.

If the initial key is directly transformed using the target matrix, the inverse of the target matrix is used, and the inverse key is multiplied by the protection key, and the obtained operation result is the initial key. At this time, the key recovery file is the inverse matrix of the target matrix or the target matrix. Wherein, when the key recovery file is the target matrix, before the inverse transform, the corresponding inverse matrix is obtained according to the target matrix.

If the initial key is transformed using the conversion table of the target matrix, the inverse key can be reversely searched by the conversion table to find the input data corresponding to the protection key, and the initial key can be obtained. Of course, if the conversion table only saves the output result, the inverse matrix of the target matrix is also needed, and the input data is obtained by multiplying the output result and the inverse matrix to obtain the initial key.

In summary, in the method of the embodiment of the present invention, after obtaining an invertible matrix as the target matrix in the matrix library, the initial key for encrypting the target file is transformed according to the target matrix to generate a protection key, and the The protection key and its key recovery file are stored in a dynamic file library. In this way, after the installation package is packaged, when the application terminal runs the installation package, the protection key can be reverse transformed to the initial key by using the key recovery file in the dynamic file, and then the target file is decrypted using the initial key. By transforming the initial key, the plaintext encryption key cannot be obtained without permission, and the target file cannot be decrypted, thereby improving the security performance.

Embodiment 2

As shown in FIG. 4, an embodiment of the present invention further provides a key conversion method, where the method includes:

Step 21: Acquire a key recovery file and a protection key stored in the dynamic library file.

Step 22: Perform inverse transformation on the protection key according to the key recovery file to obtain an initial key.

In this embodiment, when the installation package is run, the key recovery file and the protection key stored in the dynamic library file are obtained, and then the protection key is inversely transformed into the initial key by the key recovery file, and then the initial key is used. The key decrypts the target file, so that the plaintext encryption key cannot be obtained without permission, so that the target file cannot be decrypted, and the security performance is improved.

The key recovery file is the target matrix, an inverse matrix of the target matrix, or a corresponding conversion table of the target matrix;

Optionally, step 22 includes:

Multiplying the protection key by an inverse matrix of the target matrix, and the obtained operation result is an initial key; or

The first input data and the second input data corresponding to the protection key are searched in the conversion table, and all the first input data and the second input data obtained are initial keys.

Since the conversion method of the initial key is different, the key recovery file is a target matrix, an inverse matrix of the target matrix, or a corresponding conversion table of the target matrix.

Optionally, if the initial key is directly transformed by using the target matrix, when the inverse transform is performed, the protection key is multiplied by the inverse matrix by using the inverse matrix of the target matrix, and the obtained operation result is the initial key. Thus, the key recovery file is the inverse matrix of the target matrix or the target matrix. Wherein, when the key recovery file is the target matrix, before the inverse transform, the corresponding inverse matrix is obtained according to the target matrix.

If the initial key is transformed using the conversion table of the target matrix, the inverse key can be reversely searched by the conversion table to find the input data corresponding to the protection key, and the initial key can be obtained. At this time, the key recovery file is a conversion table. Of course, if the conversion table only saves the output result, the inverse matrix of the target matrix is also needed, and the input data is obtained by multiplying the output result and the inverse matrix to obtain the initial key.

In summary, the method in the embodiment of the present invention obtains a key recovery file and a protection key in a dynamic library file, and then restores the protection key inverse transformation to an initial key through the key recovery file, and then uses the initial key. The key decrypts the target file, so that the plaintext cannot be obtained without permission. The encryption key prevents the target file from being decrypted, improving security.

Embodiment 3

As shown in FIG. 5, an embodiment of the present invention further provides a key conversion apparatus, where the apparatus includes:

The first obtaining module 10 is configured to acquire a target matrix in the matrix library, where the target matrix is an invertible matrix;

The protection key generation module 20 is configured to: after encrypting the target file by using the initial key, transform the initial key according to the target matrix to generate a protection key;

The storage module 30 is configured to store the protection key and the key recovery file of the protection key into a dynamic library file; wherein the protection key can be restored to an initial state by the key recovery file inverse transformation Key.

Wherein, the device further comprises:

a second acquiring module, configured to acquire all matrices satisfying the first rule, to obtain a matrix set, where the first rule is a binary matrix whose matrix is N×N, where N is an integer greater than or equal to 2;

The third obtaining module is configured to obtain a preset number of all matrices satisfying the second rule in the matrix set to obtain a matrix library, where the second rule is that the matrix is a reversible matrix.

The protection key generation module is specifically:

a first protection key generation submodule, configured to multiply the initial key by the target matrix, and obtain an operation result as a protection key;

The second protection key generation submodule is configured to generate a conversion table according to the target matrix, search for a transformation result of the initial key in the transformation table, and use the transformation result as a protection key.

The second protection key generation submodule includes:

a first setting unit configured to set the first input data and the second input data;

An arithmetic unit configured to multiply the combined data of the first input data and the second input data by the target matrix to obtain all output results;

The first conversion table generating unit is configured to generate a conversion table based on the values of the first input data and the second input data and the output result.

Optionally, the second protection key generation submodule includes:

a second setting unit configured to set the first input data and the second input data;

a first obtaining unit, configured to acquire, when the first input data is 0, a combination of the first input data and the second input data by a first output result obtained by multiplying the target matrix;

a second obtaining unit, configured to acquire, when the second input data is 0, the combined data of the first input data and the second input data is multiplied by the second output result obtained by the target matrix;

The second conversion table generating unit is configured to generate a conversion table according to the values of the first input data and the second input data and the first output result and the second output result.

The first input data and the second input data are hexadecimal numbers.

Optionally, the second protection key generation submodule further includes:

The data form transformation unit is configured to perform transformation of the initial key into a data form according to the data form of the first input data and the second input data to obtain a transformation initial key;

The searching unit is configured to search for a corresponding transformation result in the transformation table according to the transformation initial key.

The key recovery file is the target matrix, an inverse matrix of the target matrix, or a corresponding conversion table of the target matrix.

In the apparatus of the embodiment of the present invention, after obtaining an invertible matrix as a target matrix in the matrix library, the initial key for encrypting the target file is transformed according to the target matrix to generate a protection key, and the protection key and the protection key thereof are The key recovery file is stored in a dynamic file library. In this way, after the installation package is packaged, when the application terminal runs the installation package, the protection key can be reverse transformed to the initial key by using the key recovery file in the dynamic file, and then the target file is decrypted using the initial key. The transformation of the initial key makes it impossible to obtain the plaintext encryption key without permission, thereby failing to decrypt the target file and improving the security performance.

It should be noted that the device is a device corresponding to the key conversion method for converting the initial key. The implementation of the key conversion method in the first embodiment is applicable to the device, and the same technical effect can be achieved.

Embodiment 4

As shown in FIG. 6, an embodiment of the present invention further provides a key conversion apparatus, where the apparatus includes:

The second obtaining module 40 is configured to obtain a key recovery file and a security file saved in the dynamic library file. Protection key

The protection key inverse transform module 50 is configured to inverse transform the protection key according to the key recovery file to obtain an initial key.

The key recovery file is the target matrix, an inverse matrix of the target matrix, or a corresponding conversion table of the target matrix;

Optionally, the protection key inverse transform module includes:

a first initial key inverse transform submodule, configured to multiply the protection key by an inverse matrix of the target matrix, and obtain an operation result as an initial key;

a second initial key inverse transform submodule configured to search for the first input data and the second input data corresponding to the protection key in the conversion table, and obtain all initial input data and second input data as initial Key.

The device of the embodiment of the present invention obtains the key recovery file and the protection key in the dynamic library file, and then restores the protection key inverse transformation to the initial key through the key recovery file, and then decrypts the target file by using the initial key. The encryption key of the plaintext cannot be obtained without permission, so that the target file cannot be decrypted, and the security performance is improved.

It should be noted that the device is a device corresponding to the key conversion method for restoring the protection key inverse transform to the initial key, and the implementation manner of the key conversion method in the second embodiment is applicable to the device. The same technical effect.

Embodiment 5

Embodiments of the present invention also provide a terminal comprising the key conversion apparatus as described above.

After acquiring an invertible matrix as a target matrix in the matrix library, the terminal that encrypts the target file is transformed according to the target matrix to generate a protection key, and the protection key and the The key recovery file is stored in a dynamic file library. In this way, after the installation package is packaged, when the application terminal runs the installation package, the protection key can be reverse transformed to the initial key by using the key recovery file in the dynamic file, and then the target file is decrypted using the initial key. The transformation of the initial key makes it impossible to obtain the plaintext encryption key without permission, thereby failing to decrypt the target file and improving the security performance.

It should be noted that the terminal is a terminal corresponding to the key conversion method for transforming the initial key, and the implementation manner of the key conversion method in the first embodiment is applicable to the terminal, and can also be achieved. The same technical effect.

Embodiment 6

Embodiments of the present invention also provide a terminal comprising the key conversion apparatus as described above.

The terminal in the embodiment of the present invention acquires the key recovery file and the protection key in the dynamic library file, and then restores the protection key inverse transformation to the initial key through the key recovery file, and then decrypts the target file by using the initial key. The encryption key of the plaintext cannot be obtained without permission, so that the target file cannot be decrypted, and the security performance is improved.

It should be noted that the terminal is a terminal corresponding to the key conversion method for restoring the protection key inverse transform to the initial key. The implementation manner of the key conversion method in the second embodiment is applicable to the terminal, and can also achieve the same. Technical effect.

Example 7

The embodiment of the present invention further provides a computer readable storage medium, which stores program instructions, and implements a key conversion method provided by Embodiment 1 of the present invention when the program instructions are executed by the processor.

Example eight

The embodiment of the present invention further provides a computer readable storage medium, which stores program instructions, and when the program instructions are executed by the processor, a key conversion method provided by Embodiment 2 of the present invention can be implemented.

In an embodiment of the invention, the modules may be implemented in software for execution by various types of processors. For example, an identified executable code module can comprise one or more physical or logical blocks of computer instructions, which can be constructed, for example, as an object, procedure, or function. Nonetheless, the executable code of the identified modules need not be physically located together, but may include different instructions stored in different bits that, when logically combined, constitute a module and implement the provisions of the module. purpose.

Industrial applicability

According to the technical solution of the present invention, by changing the initial key, the encryption key of the plaintext cannot be obtained without permission, so that the target file cannot be decrypted, and the security performance is improved.

Claims (22)

A key conversion method includes: Obtaining a target matrix in the matrix library, the target matrix being an invertible matrix; After the target file is encrypted by using the initial key, the initial key is transformed according to the target matrix to generate a protection key; And storing the protection key and the key recovery file of the protection key into a dynamic library file; wherein the protection key can be restored to an initial key by inverse transformation of the key recovery file. The key conversion method according to claim 1, wherein the step of constructing the matrix library comprises: Obtaining all the matrices satisfying the first rule, and obtaining a matrix set, where the first rule is a binary matrix whose matrix is N×N, where N is an integer greater than or equal to 2; Obtaining a preset number of all matrices satisfying the second rule in the matrix set to obtain a matrix library, and the second rule is that the matrix is an invertible matrix. The key conversion method according to claim 1, wherein the transforming the initial key according to the target matrix to generate a protection key comprises: Multiplying the initial key by the target matrix, and the obtained operation result is a protection key; or Generating a conversion table according to the target matrix, searching a transformation result of the initial key in the transformation table, and using the transformation result as a protection key. The key conversion method according to claim 3, wherein the generating a conversion table according to the target matrix comprises: Setting first input data and second input data; Multiplying the combined data of the first input data and the second input data by the target matrix to obtain all output results; A conversion table is generated based on the values of the first input data and the second input data and the output result. The key conversion method according to claim 3, wherein the generating a conversion table according to the target matrix comprises: Setting first input data and second input data; When the first input data is 0, the combined data of the first input data and the second input data is multiplied by the first output result obtained by the target matrix; When the second input data is 0, the combined data of the first input data and the second input data is multiplied by the second output result obtained by the target matrix; A conversion table is generated based on the values of the first input data and the second input data and the first output result and the second output result. The key conversion method according to claim 4 or 5, wherein the first input data and the second input data are hexadecimal numbers. The key conversion method according to claim 4 or 5, wherein the searching for the transformation result of the initial key in the conversion table comprises: And converting, according to the data form of the first input data and the second input data, the initial key into a data form to obtain a transformed initial key; Finding a corresponding transform result in the conversion table according to the transform initial key. The key conversion method according to claim 3, wherein the key recovery file is the target matrix, an inverse matrix of the target matrix, or a conversion table corresponding to the target matrix. A key conversion method includes: Obtain the key recovery file and protection key saved in the dynamic library file; The protection key is inversely transformed according to the key recovery file to obtain an initial key. The key conversion method according to claim 9, wherein the key recovery file is the target matrix, an inverse matrix of the target matrix, or a conversion table corresponding to the target matrix; The performing the inverse transformation on the protection key according to the key recovery file to obtain an initial key, including: Multiplying the protection key by an inverse matrix of the target matrix, and the obtained operation result is an initial key; or The first input data and the second input data corresponding to the protection key are searched in the conversion table, and all the first input data and the second input data obtained are initial keys. A key conversion device includes: a first acquiring module, configured to acquire a target matrix in the matrix library, where the target matrix is an invertible matrix; a protection key generation module, configured to: after encrypting the target file by using the initial key, transform the initial key according to the target matrix to generate a protection key; a storage module, configured to store the protection key and the key recovery file of the protection key into a dynamic library file; wherein the protection key can be restored to an initial density by inverse transformation of the key recovery file key. The key conversion device of claim 11, wherein the device further comprises: a second acquiring module, configured to acquire all matrices satisfying the first rule, to obtain a matrix set, where the first rule is a binary matrix whose matrix is N×N, where N is an integer greater than or equal to 2; The third obtaining module is configured to obtain a preset number of all matrices satisfying the second rule in the matrix set to obtain a matrix library, where the second rule is that the matrix is a reversible matrix. The key conversion device according to claim 11, wherein the protection key generation module comprises: a first protection key generation submodule, configured to multiply the initial key by the target matrix, and obtain an operation result as a protection key; The second protection key generation submodule is configured to generate a conversion table according to the target matrix, search for a transformation result of the initial key in the transformation table, and use the transformation result as a protection key. The key conversion device according to claim 13, wherein the second protection key generation submodule comprises: a first setting unit configured to set the first input data and the second input data; An arithmetic unit configured to multiply the combined data of the first input data and the second input data by the target matrix to obtain all output results; The first conversion table generating unit is configured to generate a conversion table based on the values of the first input data and the second input data and the output result. The key conversion device according to claim 13, wherein the second protection key generation submodule comprises: a second setting unit configured to set the first input data and the second input data; a first obtaining unit, configured to acquire, when the first input data is 0, a combination of the first input data and the second input data by a first output result obtained by multiplying the target matrix; a second obtaining unit, configured to: when the second input data is 0, the first input data and The combined data of the second input data is multiplied by the second output result obtained by the target matrix; The second conversion table generating unit is configured to generate a conversion table according to the values of the first input data and the second input data and the first output result or the second output result. The key conversion device according to claim 14 or 15, wherein said first input data and said second input data are hexadecimal numbers. The key conversion device according to claim 14 or 15, wherein the second protection key generation sub-module further comprises: The data form transformation unit is configured to perform transformation of the initial key into a data form according to the data form of the first input data and the second input data to obtain a transformation initial key; The searching unit is configured to search for a corresponding transformation result in the transformation table according to the transformation initial key. The key conversion device according to claim 13, wherein the key recovery file is the target matrix, an inverse matrix of the target matrix, or a corresponding conversion table of the target matrix. A key conversion device includes: a second obtaining module, configured to obtain a key recovery file and a protection key stored in the dynamic library file; The protection key inverse transform module is configured to inverse transform the protection key according to the key recovery file to obtain an initial key. The key conversion device according to claim 19, wherein the key recovery file is the target matrix, an inverse matrix of the target matrix, or a corresponding conversion table of the target matrix; The protection key inverse transform module includes: a first initial key inverse transform submodule, configured to multiply the protection key by an inverse matrix of the target matrix, and obtain an operation result as an initial key; a second initial key inverse transform submodule configured to search for the first input data and the second input data corresponding to the protection key in the conversion table, and obtain all initial input data and second input data as initial Key. A terminal comprising the key conversion device according to any one of claims 11-18. A terminal comprising the key conversion device according to claim 19 or 20.

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