CN104462959A - Reinforcement protection method, sever and system for android app - Google Patents

Abstract

The invention discloses a reinforcement protection method, a server and a system for an Android application. The method includes: obtaining the original Android installation package APK of the Android application; decompiling the original APK, extracting the protected method code from it, and extracting The position is filled with nop; the extracted protected method code is encrypted according to the specified encryption and decryption strategy to generate a hardened configuration file; the specified encryption and decryption strategy, the hardened configuration file and the hardened protection program are added to the decompiled In the APK, compile and generate the reinforced APK of the Android application. The technical solution provided by the present invention realizes the dynamic encryption and decryption of the protected method, so that there is no complete dex image in the memory at any time, thereby preventing the complete dex file from being obtained through the memory dump, thereby greatly reducing the reverse engineering of Android applications Analysis, and then the possibility of repackaging and redistribution.

Description

A reinforcement protection method, server and system for Android applications

technical field

The invention relates to the field of data security, in particular to a reinforcement protection method, server and system for Android applications.

Background technique

The rapid development of the Android system and the rapid growth of devices have produced a large number of third-party applications. Compared with other operating systems, the open source of the Android system provides application developers with more functional interfaces. These functional interfaces are improving The scalability of the system also provides convenience for malicious software. Illegal copying, reverse engineering, decompilation, debugging, cracking, secondary packaging, memory interception and other methods continue to threaten the security of the Android system, not only endangering users, but also It also causes serious damage to normal application developers.

The existing reinforcement schemes for the Android software installation package are mainly divided into three types: the first is to completely encrypt the entire dex file; the second is to deform the bytecode of the dex file during runtime to prevent direct Dump of the complete dex , the existing methods cannot be well customized, and this solution needs to perform bytecode transformation functions; the third method is to use the first two solutions in combination. However, because the above solution has a complete dex image in the memory for a certain period of time when the APK is running, the protected dex can be completely restored by means of a memory dump. As a result, the existing solution cannot completely solve the security problems faced by the Android installation package. problems, and people are always looking for more effective solutions.

Contents of the invention

In view of the above problems, the present invention is proposed to provide an Android application reinforcement protection method, server and system that overcome the above problems or at least partially solve the above problems. .

According to one aspect of the present invention, a method for strengthening and protecting an Android application is provided, the method comprising:

Obtain the original Android installation package APK of the Android application;

decompile the original APK, extract the protected method code therefrom, and fill the extraction position with nop;

Encrypt the extracted protected method code according to the specified encryption and decryption strategy to generate a hardened configuration file;

Adding the specified encryption and decryption strategy, the hardened configuration file and the hardened protection program to the decompiled APK, compiling and generating the hardened APK of the Android application;

Wherein, the hardened protection program performs the following operations when the hardened APK of the Android application is installed and running: dynamically apply for space according to the invocation of the protected method, and when the protected method is called, according to the added The decryption policy decrypts the corresponding method in the hardening configuration file to obtain the protected method code; when the call of the protected method ends, re-encrypts the decrypted protected method code according to the encryption and decryption strategy.

Optionally, the protected method code is identified by annotation in the original APK;

The decompiling the original APK, and extracting the protected method code therefrom includes: decompiling the original APK, and extracting the protected method code therefrom according to the method annotation therein.

Optionally, the specified encryption and decryption strategy includes one or more of the following:

Anti-debugging strategy;

Anti-Dump strategy;

Anti-repackaging strategy;

String encryption and decryption strategy.

Optionally, adding the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program to the decompiled APK includes:

Write the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program into the SO file under the lib directory of the decompiled APK.

Optionally, the protected method code is the core content in the dex file in the original APK of the Android application.

Optionally, the obtaining the original Android installation package APK of the Android application includes: receiving the original APK of the Android application uploaded by the user through the reinforcement protection client;

The method further includes: providing an interface for downloading the hardened APK, so that the user can use the hardened protection client to download the hardened APK through the interface.

Optionally, the method further includes:

The encryption and decryption strategy selection instruction, encryption password and decryption password uploaded by the user through the reinforcement protection client are received, and the specified encryption and decryption strategy is determined accordingly.

Optionally, the method further includes:

Receive the identity uploaded by the user through hardening and protecting the client, and use the identity to sign the reinforced APK.

Optionally, the method further includes:

Perform automatic installation tests on hardened APKs.

According to another aspect of the present invention, a reinforcement protection server for Android applications is provided, the server includes:

An acquisition unit, adapted to acquire the original Android installation package APK of the Android application;

The decompilation extraction unit is adapted to decompile the original APK, extract the protected method code therefrom, and fill the extraction position with nop;

An encryption unit is adapted to encrypt the extracted protected method code according to a specified encryption and decryption strategy to generate a hardened configuration file;

Adding a compilation unit, suitable for adding the specified encryption and decryption strategy, the reinforcement configuration file and the reinforcement protection program to the decompiled APK, compiling and generating the reinforcement APK of the Android application;

Wherein, the hardened protection program performs the following operations when the hardened APK of the Android application is installed and running: dynamically apply for space according to the invocation of the protected method, and when the protected method is called, according to the added The decryption policy decrypts the corresponding method in the hardening configuration file to obtain the protected method code; when the call of the protected method ends, re-encrypts the decrypted protected method code according to the encryption and decryption strategy.

Optionally, the protected method code is identified through annotations in the original APK obtained by the obtaining unit;

The decompiling and extracting unit is adapted to decompile the original APK, and extract protected method codes therefrom according to method annotations therein.

Optionally, the encryption unit is adapted to encrypt the extracted protected method code according to one or more of the following strategies:

Anti-debugging strategy;

Anti-Dump strategy;

Anti-repackaging strategy;

String encryption and decryption strategy.

Optionally, the adding and compiling unit is adapted to write the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program into the SO file under the lib directory of the decompiled APK.

Optionally, the decompiling and extracting unit is adapted to decompile the original APK and then extract the core content in the dex file therein.

Optionally, the obtaining unit is adapted to receive the original APK of the Android application uploaded by the user through the reinforcement protection client.

The server further includes: a download unit adapted to provide an interface for downloading the hardened APK, so that the user can use the hardened protection client to download the hardened APK through the interface.

Optionally, the acquisition unit is further adapted to receive the encryption and decryption policy selection instruction, encryption password and decryption password uploaded by the user through the hardening and protection client, and send them to the encryption unit;

The encryption unit is adapted to determine the designated encryption and decryption strategy according to the encryption and decryption strategy selection instruction, encryption password and decryption password.

Optionally, the obtaining unit is further adapted to receive the identity uploaded by the user through the reinforcement protection client;

The server further includes: a signing unit adapted to use the identity to sign the reinforced APK.

Optionally, the server further includes:

A test unit suitable for automatic installation testing of hardened APKs.

According to one aspect of the present invention, a hardening protection system for Android applications is provided, including: a hardening protection client and the hardening protection server described in any one of the above items.

As can be seen from the above, the technical solution provided by the present invention adds the encryption and decryption strategy, the reinforcement protection program and the protected method code to the encrypted reinforcement configuration file into the decompiled APK to generate the reinforcement APK of the Android application. The protection program dynamically decodes the protected method when it is called, and encrypts it after the protected method is called, realizing the dynamic encryption and decryption of the protected method, so that there is no complete memory at any time dex image, so as to prevent the complete dex file from being obtained through memory dump, thereby greatly reducing the possibility of Android applications being reversed and repackaged and redistributed.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the specific embodiments of the present invention are enumerated below.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating a preferred embodiment and are not to be considered as limiting the invention. Also throughout the drawings, the same reference numerals are used to designate the same components. In the attached picture:

Fig. 1 shows a flow chart of a method for strengthening and protecting an Android application according to an embodiment of the present invention;

FIG. 2 shows a flowchart of a method for strengthening and protecting an Android application according to another embodiment of the present invention;

Fig. 3 shows a schematic diagram of a reinforcement protection server for an Android application according to an embodiment of the present invention;

Fig. 4 shows a schematic diagram of a reinforcement protection server for an Android application according to another embodiment of the present invention;

Fig. 5 shows a schematic diagram of a reinforcement protection server for an Android application according to yet another embodiment of the present invention;

Fig. 6 shows a schematic diagram of a reinforcement protection server for an Android application according to yet another embodiment of the present invention;

Fig. 7A shows the flowchart of the development process of the Android installation package according to one embodiment of the present invention;

FIG. 7B shows a flow chart of the reinforcement protection process of the Android installation package according to one embodiment of the present invention;

Fig. 7C shows a flow chart of the running process of the Android installation package according to one embodiment of the present invention.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

Fig. 1 shows a flow chart of a method for strengthening and protecting an Android application according to an embodiment of the present invention. As shown in Figure 1, the method includes:

Step S110, obtaining the original Android installation package APK of the Android application.

On the Android system, an application that can be installed and run needs to be packaged into an Android installation package, namely the APK (Android application package file) file format. The original Android installation package APK in this step is developed and generated by the developer.

Step S120, decompile the original APK, extract the protected method code therefrom, and fill the extraction position with nop.

The nop filling in this step refers to: filling the nop instruction to the extraction position. It is equivalent to extracting the protected method code in the original APK after decompilation, and then filling it with nop instructions.

Step S130, encrypting the extracted protected method code according to the specified encryption and decryption strategy to generate a hardening configuration file.

The encryption processing in this step can be symmetric encryption or asymmetric encryption. The encryption and decryption strategy here includes an encryption strategy and a corresponding decryption strategy.

Step S140, adding the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program to the decompiled APK, compiling and generating a hardened APK of the Android application.

The hardened protection program in this step is used to dynamically encrypt and decrypt the hardened configuration file. When the hardened APK of the Android application is installed and running, the hardened protection program performs the following operations: dynamically apply for space according to the call status of the protected method, When the protected method is called, the corresponding method in the hardened configuration file is decrypted according to the encryption and decryption strategy to obtain the protected method code; the protected method code is called to run; when the protected method is called, according to The encryption and decryption strategy re-encrypts the protected method code obtained through decryption.

The method shown in Figure 1 imports the reinforced configuration file obtained after the protected method code is encrypted, the encryption and decryption strategy, and the reinforced protection program into the APK to generate the reinforced APK of the Android application; When the method is called, it is decoded, and it is encrypted after the protected method is called, which realizes the dynamic encryption and decryption of the protected method, so that there is no complete dex image in the memory at any time, thus preventing the passing of The memory dump method is used to obtain the complete dex file, which greatly reduces the possibility of the Android application being reversely analyzed, and then repackaged and redistributed.

In general, since the developer of the Android installation package APK and the protector who provides protection services for the APK are different parties, the developer can use annotations to identify the method the developer wants to be protected during the process of developing the original APK. The protector then extracts the protected method code from the source code of the original APK according to the annotation. The "annotation" here means that JAVA provides a function called annotation (annotation) starting from J2SE5, which is used to put any information or metadata Associated with program elements (classes, methods, member variables, etc.), it will not have any impact on the execution of source code or class, etc.

In one embodiment of the present invention, in the method shown in FIG. 1, the protected method code is identified through annotations in the original APK obtained in step S110; correspondingly, the decompiled original APK in step S120 extracts The protected method code can be obtained by: decompiling the original APK, and extracting the protected method code from it according to the method annotations therein.

Figure 7A shows a flow chart of the development process of the Android installation package according to one embodiment of the present invention. In this embodiment, for developers, the development process of the Android installation package is as shown in Figure 7A, step S710 to step S750 description The following process is carried out: start developing the Android installation package APK, judge whether a method is a protected method, and add annotations to the protected method code if it is, otherwise do not add annotations, and generate the original Android installation package APK. FIG. 7B shows a flow chart of the reinforcement protection process of the Android installation package according to one embodiment of the present invention. For the protector who provides protection services for the APK, the reinforcement protection process of the Android installation package is shown in 7B, step S810 to step S870 The following process is described: after obtaining the original Android installation package APK, decompile the original APK, select the specified encryption and decryption strategy, and then encrypt the protected method code according to the annotation provided by the developer, generate a hardened configuration file, and The hardened configuration file, encryption and decryption policy, and hardened protection program are imported into the APK to generate a hardened APK. Step S880 in FIG. 7B further signs the hardened APK, and this step S880 will be described in detail below.

For example, when a developer is developing an instant messaging application, he wants to protect the image transmission function. Therefore, the developer adds corresponding annotations to the method code of the image transmission function during the development process, marking the method as a protected method. , to package protected methods, unprotected methods, and related configuration information to generate the original APK. The protector obtains the original APK in the process of hardening and protection, and after decompiling the APK, extracts the method code of the image transmission function according to the above annotation, selects the specified encryption and decryption strategy for encryption processing, and generates the hardening configuration file described above; Then put the hardened configuration file, encryption and decryption strategy, and hardened protection program into the decompiled APK, and compile the hardened APK of the instant messaging application.

In one embodiment of the present invention, the designated encryption and decryption strategy used in the encryption and decryption process in the reinforcement protection process shown in Figure 1 may include one or more of the following: anti-debugging strategy; anti-dump strategy; anti-dump strategy; Repackaging strategy; string encryption and decryption strategy. Among them, the anti-debugging strategy can prevent dynamic debugging; the anti-dump strategy can prevent dynamic dump from complete dex; anti-repackaging can prevent APK from being repackaged; the string encryption and decryption strategy can realize the encryption of strings in dex to prevent static analysis See the plaintext program directly.

In one embodiment of the present invention, the step S140 of the method shown in FIG. 1 adds the specified encryption and decryption strategy, hardening configuration file and hardening protection program to the decompiled APK, including: adding the specified encryption and decryption strategy, hardening The configuration file and hardening protection program are written into the SO file under the lib directory of the decompiled APK.

The internal file structure of the decompiled APK is shown in Table 1:

Table 1

file name illustrate META-INF\ certificate file res\ resource assets\ Additional resource files resources.arsc binary resource file classes.dex .Source resource file AndroidManifest.xml global configuration file lib\ add-ons

Among them, there are generally MANIFEST.MF and files ending with .RSA and .SF in the META-INF directory, which record the certificate signatures of other directory files. When the Android system installs the APK, it will check whether each file in the APK is consistent with the records in this directory. The signatures of the certificates are consistent. If they are inconsistent, the file is considered to have been tampered with, and the installation and operation of the APK is refused.

The res directory stores files such as image resources and interface layouts.

The assets directory stores additional resources and configuration files, such as TXT or HTML documentation, font files, and image resources.

The resources.arsc file is a compiled binary resource file.

The class.dex file is a Java bytecode file generated after Java source code compilation, and .dex is the abbreviation of DalvikExecutable (Dalvik virtual machine executable file).

The AndroidManifest.xml file is the global description file of the Android installation package, which records information such as the package name, version number, permissions, referenced library files, module entries, and classes of the application.

The lib directory is a JNI (Java Native Interface) library file, and generally stores some SO files in the armeabi subfolder. The SO file is a library file under linux, and it is a dynamic link library file in ELF format. This type of file is dynamically loaded into the program when the program needs to run, and the suffix is .so. In this embodiment, the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program are written into the SO file under the lib directory of the APK. When running the hardened APK to call a protected method, it is dynamically loaded in the form of an SO file.

In one embodiment of the present invention, the protected method code in the method shown in FIG. 1 is the core content in the dex file in the original APK of the Android application.

Fig. 2 shows a flowchart of a method for strengthening and protecting an Android application according to another embodiment of the present invention. As shown in Figure 2, the method includes:

Step S210, receiving the original APK of the Android application uploaded by the user through the reinforcement protection client. In this step, the original APK uploaded by the user (that is, the developer) is received, and the development process of the original APK is shown in FIG. 7A , which will not be repeated here.

Step S220, decompile the original APK, extract the protected method code therefrom, and fill the extraction position with nop.

Step S230, encrypting the extracted protected method code according to the specified encryption and decryption strategy to generate a hardening configuration file.

Step S240, adding the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program to the decompiled APK, compiling and generating the hardened APK of the Android application.

The steps S220, S230, and S240 described above are the same as the steps S120, S130, and S140 of the method shown in Figure 1, and describe the process of hardening and protecting the original APK. Figure 7B also illustrates this process from the perspective of the protector. For demonstration purposes, no further details are given here.

Step S250, providing an interface for downloading the hardened APK, so that the user can use the hardened protection client to download the hardened APK through the interface.

It can be seen from the above that the solution shown in Figure 2 provides developers with a platform for hardening and protecting Android applications. After receiving the unprotected original APK uploaded by the developer, after hardening and protection processing, it provides the developer with a download Reinforce the interface of APK.

In one embodiment of the present invention, the specified encryption and decryption strategies in the methods shown in Fig. 1 and Fig. 2 can be determined through the encryption and decryption related information provided by the user (that is, the developer), that is, the user independently formulates the encryption and decryption strategy and encryption Decrypt the password. The method further includes: receiving an encryption and decryption strategy selection instruction, an encryption password and a decryption password uploaded by the user through the reinforcement protection client, and determining the designated encryption and decryption strategy accordingly. Wherein, the encryption and decryption information provided by the user can also be marked in the annotation of the protected method. This solution provides great convenience for the developer, enabling the developer to realize the convenient configurability of the protection function in the development stage of the application.

Each released APK has a unique ID to identify the legitimacy of the application. This ID is the signature of the APK. The APK with the same signature can be overwritten and installed. Therefore, in order to prevent hackers from illegally tampering and misappropriating the APK, it is necessary to strengthen the The APK is signed, the process of signing the reinforced APK in step S880 as shown in FIG. 7B . In an embodiment of the present invention, the method shown in FIG. 2 further includes: receiving the identity uploaded by the user through the hardening protection client, and using the identity to sign the reinforced APK.

In order to ensure the effectiveness of APK hardening and avoid the phenomenon that APK cannot be installed or APK encryption fails due to mistakes, it is possible to further test it before providing users with downloaded hardened APK. In an embodiment of the present invention, the method shown in FIG. 2 further includes: performing an automatic installation test on the reinforced APK.

Fig. 3 shows a schematic diagram of a hardening protection server for an Android application according to an embodiment of the present invention. As shown in Figure 3, the reinforced protection server 300 of this Android application includes:

The obtaining unit 310 is adapted to obtain the original Android installation package APK of the Android application.

On the Android system, an application that can be installed and run needs to be packaged into an Android installation package, that is, the APK (Android application package file) file format. The original Android installation package APK obtained by this unit is developed and generated by the developer.

The decompiling and extracting unit 320 is adapted to decompile the original APK, extract the protected method code therefrom, and fill the extraction position with nop.

The nop filling here refers to: filling the nop instruction to the extraction position, so that the filled code is aligned with the source code.

The encryption unit 330 is adapted to perform encryption processing on the extracted protected method code according to a specified encryption and decryption strategy to generate a hardening configuration file.

The adding compiling unit 340 is adapted to add the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program to the decompiled APK, and compile and generate the hardened APK of the Android application.

Among them, the hardening protection program performs the following operations when the hardened APK of the Android application is installed and running: dynamically apply for space according to the call situation of the protected method, and when the protected method is called, the hardened configuration file is encrypted according to the encryption and decryption strategy. The corresponding method in decryption to obtain the protected method code; when the call of the protected method is completed, the protected method code obtained by decryption is re-encrypted according to the encryption and decryption strategy.

It can be seen that the reinforcement protection server 300 shown in FIG. 3 imports the reinforcement configuration file obtained after encrypting the encryption and decryption strategy, the reinforcement protection program and the protected method code into the APK to generate the reinforcement APK of the Android application; Decode the protected method when it is called, and encrypt it after the protected method is called, so that there is no complete dex image in the memory at any time, thus preventing the complete dex image from being obtained through memory dump. dex file, which greatly reduces the possibility of the Android application being reversely analyzed, and then repackaged and redistributed.

According to the above-mentioned example where the developer uses the annotation to make the protector extract the method code that the developer wants to be protected according to the annotation, and strengthen and protect it, in one embodiment of the present invention, the server shown in Figure 3 The protected method codes are identified by annotations in the original APK obtained by the acquisition unit 310; the decompilation extraction unit 320 is adapted to decompile the original APK, and extract the protected method codes therefrom according to the method annotations therein.

In one embodiment of the present invention, the encryption unit 330 of the server shown in FIG. 3 is adapted to encrypt the extracted protected method code according to one or more of the following strategies: anti-debugging strategy; anti-dump strategy; Anti-repackaging strategy; string encryption and decryption strategy. Among them, the anti-debugging strategy can prevent dynamic debugging; the anti-dump strategy can prevent dynamic dump from complete dex; anti-repackaging can prevent APK from being repackaged; the string encryption and decryption strategy can realize the encryption of strings in dex to prevent static analysis See the plaintext program directly.

In one embodiment of the present invention, the add compilation unit 340 of the server shown in Figure 3 is adapted to write the specified encryption and decryption strategy, reinforcement configuration file and reinforcement protection program into the SO file under the lib directory of the decompiled APK . In this embodiment, the specified encryption and decryption policy, the hardening configuration file and the hardening protection program are written into the SO file under the lib directory of the APK shown in Table 1.

In one embodiment of the present invention, the decompiling and extracting unit 320 of the server shown in FIG. 3 is adapted to decompile the original APK and then extract the core content in the dex file therein.

Fig. 4 shows a schematic diagram of a hardening protection server for an Android application according to another embodiment of the present invention. As shown in FIG. 4 , the reinforcement protection server 400 for the Android application includes: an obtaining unit 410 , a decompiling and extracting unit 420 , an encryption unit 430 , an adding and compiling unit 440 and a downloading unit 450 .

Among them, the decompilation and extraction unit 420, the encryption unit 430, and the addition and compilation unit 440 are respectively the same as the decompilation and extraction unit 320, the encryption unit 330, and the addition and compilation unit 340 of the server shown in FIG. The process, and Figure 7B also shows the process from the perspective of the protector, so I won't repeat it here.

The obtaining unit 410 is adapted to receive the original APK of the Android application uploaded by the user through the reinforcement protection client.

This unit is suitable for receiving the original APK uploaded by the user (that is, the developer). The development process of the original APK is shown in FIG. 7A , which will not be repeated here.

The download unit 450 is adapted to provide an interface for downloading the hardened APK, so that the user can use the hardening protection client to download the hardened APK through this interface.

As can be seen from the above, the server shown in Figure 4 provides a platform for developers to strengthen and protect Android applications. The acquisition unit 410 receives the unprotected original APK uploaded by the developer, and decompiles the extraction unit 420. After the hardening and protection processing by the unit 430 and the adding and compiling unit 440 , the download unit 450 provides the developer with an interface for downloading the hardened APK.

In one embodiment of the present invention, the encryption and decryption strategy specified in the encryption unit of the server shown in Fig. 3 and Fig. 4 can be determined through the encryption and decryption related information provided by the user (that is, the developer), that is, the user independently formulates the encryption and decryption strategy and encryption and decryption passwords. The acquisition unit 410 of the server shown in Figure 4 is further adapted to receive the encryption and decryption policy selection instruction, encryption password and decryption password uploaded by the user through the reinforcement protection client, and send them to the encryption unit 430; the encryption unit 430 is adapted to encrypt and decrypt according to the The strategy selection command, encryption password and decryption password determine the specified encryption and decryption strategy. Among them, the encryption and decryption information provided by the user can also be marked in the annotation of the protected method. This solution provides great convenience for the developer, enabling the developer to realize the convenient configurability of the protection function during the development stage of the application.

Fig. 5 shows a schematic diagram of a hardening protection server for an Android application according to yet another embodiment of the present invention. As shown in FIG. 5 , the reinforcement protection server 500 for the Android application includes: an acquisition unit 510 , a decompilation extraction unit 520 , an encryption unit 530 , an addition and compilation unit 540 , a download unit 550 and a signature unit 560 .

In this embodiment, the reinforcement protection server 500 needs to sign the reinforcement APK in order to prevent illegal tampering and misappropriation of the APK by hackers. Therefore, compared with the servers shown in FIGS. 3 and 4 , this server adds a signature unit 560 . Wherein, obtaining unit 510, decompiling and extracting unit 520, encrypting unit 530, adding and compiling unit 540, and downloading unit 550 are respectively connected with obtaining unit 410, decompiling and extracting unit 420, encrypting unit 430, and adding and compiling unit 440 of the server shown in FIG. , and the downloading unit 450 are correspondingly the same, and will not be repeated here.

The obtaining unit 510 is further adapted to receive the identity uploaded by the user through the reinforcement protection client.

The signing unit 560 is adapted to use the identity to sign the reinforced APK.

Fig. 6 shows a schematic diagram of a hardening protection server for an Android application according to yet another embodiment of the present invention. As shown in FIG. 6 , the reinforcement protection server 600 of the Android application includes: an acquisition unit 610 , a decompilation extraction unit 620 , an encryption unit 630 , an addition compilation unit 640 , a download unit 650 , a signature unit 660 and a test unit 670 .

In this embodiment, in order to ensure the effectiveness of APK reinforcement and avoid the phenomenon that APK cannot be installed and APK encryption fails due to mistakes, the reinforcement protection server 600 can further test it before providing users with downloaded reinforcement APK. Therefore, compared with the server described above, this server adds a testing unit 670 . Among them, the acquisition unit 610, the decompilation extraction unit 620, the encryption unit 630, the addition and compilation unit 640, the download unit 650, and the signature unit 660 are respectively connected with the acquisition unit 510, decompilation extraction unit 520, encryption unit 530, The compiling unit 540, the downloading unit 550, and the signing unit 560 are correspondingly the same, and will not be repeated here.

The testing unit 670 is suitable for performing an automatic installation test on the reinforced APK.

Based on the above-mentioned embodiments, after the developer releases the hardened APK that has been hardened and protected to the Android application market, the user will download and run the hardened APK. Figure 7C shows a flow chart of the running process of the Android installation package according to one embodiment of the present invention. From the user's point of view, the running process of the Android installation package APK is as shown in Figure 7C, and steps S902 to S920 describe the following Process: To run the APK, first obtain the running permission by reading the key, then read the APK configuration file, and then call the method in the APK to determine whether the currently called method is a protected method, if the currently called method is protected protected method, dynamically decrypt the protected method code, call the decrypted protected method, and then dynamically decrypt the protected method code again after the call, and continue to run the APK; if the currently called If the method is not a protected method, it will be directly called normally, and the APK will continue to run after the call is completed; run the APK with this mechanism until the entire APK running process is completed.

An embodiment of the present invention also discloses a reinforcement protection system for Android applications, which includes a reinforcement protection client and a reinforcement protection server as described in any of the above embodiments.

To sum up, the present invention provides a reinforcement protection scheme for Android applications. The reinforcement configuration file obtained after encrypting the encryption and decryption strategy, the reinforcement protection program and the protected method code is added to the decompiled APK to generate For the hardened APK of Android applications, because the hardened protection program dynamically decodes the protected method when it is called, and encrypts it after the protected method is called, the dynamic encryption and decryption of the protected method is realized, making the memory There is no complete dex image at any time, so as to prevent the complete dex file from being obtained by means of memory dump, thereby greatly reducing the possibility of reverse analysis of Android applications, and then repackaging and redistribution.

It should be noted:

The algorithms and displays presented herein are not inherently related to any particular computer, virtual appliance, or other device. Various general purpose devices can also be used with the teachings based on this. The structure required to construct such an apparatus will be apparent from the foregoing description. Furthermore, the present invention is not specific to any particular programming language. It should be understood that various programming languages can be used to implement the content of the present invention described herein, and the above description of specific languages is for disclosing the best mode of the present invention.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure the understanding of this description.

Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, in order to streamline this disclosure and to facilitate an understanding of one or more of the various inventive aspects, various features of the invention are sometimes grouped together in a single embodiment, figure, or its description. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.

Those skilled in the art can understand that the modules in the device in the embodiment can be adaptively changed and arranged in one or more devices different from the embodiment. Modules or units or components in the embodiments may be combined into one module or unit or component, and furthermore may be divided into a plurality of sub-modules or sub-units or sub-assemblies. All features disclosed in this specification (including accompanying claims, abstract and drawings) and any method or method so disclosed may be used in any combination, except that at least some of such features and/or processes or units are mutually exclusive. All processes or units of equipment are combined. Each feature disclosed in this specification (including accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will understand that although some embodiments described herein include some features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention. and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.

The various component embodiments of the present invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art should understand that a microprocessor or a digital signal processor (DSP) can be used in practice to implement some or all of some or all of the parts in the hardened protection server and system for an Android application according to an embodiment of the present invention. Or full functionality. The present invention can also be implemented as an apparatus or an apparatus program (for example, a computer program and a computer program product) for performing a part or all of the methods described herein. Such a program for realizing the present invention may be stored on a computer-readable medium, or may be in the form of one or more signals. Such a signal may be downloaded from an Internet site, or provided on a carrier signal, or provided in any other form.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The use of the words first, second, and third, etc. does not indicate any order. These words can be interpreted as names.

The invention discloses A1, a reinforcement protection method for an Android application, wherein the method includes:

Obtain the original Android installation package APK of the Android application;

decompile the original APK, extract the protected method code therefrom, and fill the extraction position with nop;

Encrypt the extracted protected method code according to the specified encryption and decryption strategy to generate a hardened configuration file;

Adding the specified encryption and decryption strategy, the hardened configuration file and the hardened protection program to the decompiled APK, compiling and generating the hardened APK of the Android application;

Wherein, the hardened protection program performs the following operations when the hardened APK of the Android application is installed and running: dynamically apply for space according to the invocation of the protected method, and when the protected method is called, according to the added The decryption policy decrypts the corresponding method in the hardening configuration file to obtain the protected method code; when the call of the protected method ends, re-encrypts the decrypted protected method code according to the encryption and decryption strategy.

A2. The method as described in A1, wherein,

The protected method code is identified by annotation in the original APK;

The decompiling the original APK, and extracting the protected method code therefrom includes: decompiling the original APK, and extracting the protected method code therefrom according to the method annotation therein.

A3. The method as described in A1, wherein the specified encryption and decryption strategy includes one or more of the following:

Anti-debugging strategy;

Anti-Dump strategy;

Anti-repackaging strategy;

String encryption and decryption strategy.

A4. The method as described in A1, wherein adding the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program to the decompiled APK includes:

Write the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program into the SO file under the lib directory of the decompiled APK.

A5. The method as described in A1, wherein,

The protected method code is the core content in the dex file in the original APK of the Android application.

A6. The method of any one of A1-A5, wherein,

The obtaining of the original Android installation package APK of the Android application includes: receiving the original APK of the Android application uploaded by the user through the reinforcement protection client;

The method further includes: providing an interface for downloading the hardened APK, so that the user can use the hardened protection client to download the hardened APK through the interface.

A7. The method as described in A6, wherein the method further comprises:

The encryption and decryption strategy selection instruction, encryption password and decryption password uploaded by the user through the reinforcement protection client are received, and the specified encryption and decryption strategy is determined accordingly.

A8, the method as described in A 6, wherein, the method further comprises:

Receive the identity uploaded by the user through hardening and protecting the client, and use the identity to sign the reinforced APK.

A 9, the method as described in A 6, wherein, the method further comprises:

Perform automatic installation tests on hardened APKs.

The present invention discloses another B10, a reinforcement protection server for Android applications, wherein the server includes:

An acquisition unit, adapted to acquire the original Android installation package APK of the Android application;

The decompilation extraction unit is adapted to decompile the original APK, extract the protected method code therefrom, and fill the extraction position with nop;

An encryption unit is adapted to encrypt the extracted protected method code according to a specified encryption and decryption strategy to generate a hardened configuration file;

Adding a compilation unit, suitable for adding the specified encryption and decryption strategy, the reinforcement configuration file and the reinforcement protection program to the decompiled APK, compiling and generating the reinforcement APK of the Android application;

Wherein, the hardened protection program performs the following operations when the hardened APK of the Android application is installed and running: dynamically apply for space according to the invocation of the protected method, and when the protected method is called, according to the added The decryption policy decrypts the corresponding method in the hardening configuration file to obtain the protected method code; when the call of the protected method ends, re-encrypts the decrypted protected method code according to the encryption and decryption strategy.

B11. The server as described in B10, wherein,

The protected method code is identified by annotation in the original APK obtained by the obtaining unit;

The decompiling and extracting unit is adapted to decompile the original APK, and extract protected method codes therefrom according to method annotations therein.

B12, the method as described in B10, wherein,

The encryption unit is adapted to encrypt the extracted protected method code according to one or more of the following strategies:

Anti-debugging strategy;

Anti-Dump strategy;

Anti-repackaging strategy;

String encryption and decryption strategy.

B13. The server as described in B10, wherein,

The adding and compiling unit is adapted to write the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program into the SO file under the lib directory of the decompiled APK.

B14. The server as described in B10, wherein,

The decompiling and extracting unit is suitable for decompiling the original APK and extracting the core content in the dex file therein.

B15. The server according to any one of B10-B14, wherein,

The acquisition unit is adapted to receive the original APK of the Android application uploaded by the user through the reinforcement protection client.

The server further includes: a download unit adapted to provide an interface for downloading the hardened APK, so that the user can use the hardened protection client to download the hardened APK through the interface.

B16. The server as described in B15, wherein,

The acquisition unit is further adapted to receive the encryption and decryption strategy selection instruction, encryption password and decryption password uploaded by the user through the reinforcement protection client, and send them to the encryption unit;

The encryption unit is adapted to determine the designated encryption and decryption strategy according to the encryption and decryption strategy selection instruction, encryption password and decryption password.

B17. The server as described in B15, wherein,

The acquisition unit is further adapted to receive the identity uploaded by the user through the reinforcement protection client;

The server further includes: a signing unit adapted to use the identity to sign the reinforced APK.

B18. The server as described in B15, wherein the server further includes:

A test unit suitable for automatic installation testing of hardened APKs.

The present invention also discloses C19, a reinforcement protection system for Android applications, comprising: a reinforcement protection client and a reinforcement protection server according to any one of claims B10-B18.

Claims (10)

1. A reinforcement protection method for an Android application, wherein the method comprises: Obtain the original Android installation package APK of the Android application; decompile the original APK, extract the protected method code therefrom, and fill the extraction position with nop; Encrypt the extracted protected method code according to the specified encryption and decryption strategy to generate a hardened configuration file; Adding the specified encryption and decryption strategy, the hardened configuration file and the hardened protection program to the decompiled APK, compiling and generating the hardened APK of the Android application; Wherein, the hardened protection program performs the following operations when the hardened APK of the Android application is installed and running: dynamically apply for space according to the invocation of the protected method, and when the protected method is called, according to the added The decryption policy decrypts the corresponding method in the hardening configuration file to obtain the protected method code; when the call of the protected method ends, re-encrypts the decrypted protected method code according to the encryption and decryption strategy. 2. The method of claim 1, wherein, The protected method code is identified by annotation in the original APK; The decompiling the original APK, and extracting the protected method code therefrom includes: decompiling the original APK, and extracting the protected method code therefrom according to the method annotation therein. 3. The method according to claim 1, wherein the specified encryption and decryption strategy includes one or more of the following: Anti-debugging strategy; Anti-Dump strategy; Anti-repackaging strategy; String encryption and decryption strategy. 4. The method according to claim 1, wherein adding the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program to the decompiled APK comprises: Write the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program into the SO file under the lib directory of the decompiled APK. 5. The method of claim 1, wherein, The protected method code is the core content in the dex file in the original APK of the Android application. 6. A reinforcement protection server for Android applications, wherein the server includes: An acquisition unit, adapted to acquire the original Android installation package APK of the Android application; The decompilation extraction unit is adapted to decompile the original APK, extract the protected method code therefrom, and fill the extraction position with nop; An encryption unit is adapted to encrypt the extracted protected method code according to a specified encryption and decryption strategy to generate a hardened configuration file; Adding a compilation unit, suitable for adding the specified encryption and decryption strategy, the reinforcement configuration file and the reinforcement protection program to the decompiled APK, compiling and generating the reinforcement APK of the Android application; Wherein, the hardened protection program performs the following operations when the hardened APK of the Android application is installed and running: dynamically apply for space according to the invocation of the protected method, and when the protected method is called, according to the added The decryption policy decrypts the corresponding method in the hardening configuration file to obtain the protected method code; when the call of the protected method ends, re-encrypts the decrypted protected method code according to the encryption and decryption strategy. 7. The server of claim 6, wherein: The protected method code is identified by annotation in the original APK obtained by the obtaining unit; The decompiling and extracting unit is adapted to decompile the original APK, and extract protected method codes therefrom according to method annotations therein. 8. The method of claim 6, wherein, The encryption unit is adapted to encrypt the extracted protected method code according to one or more of the following strategies: Anti-debugging strategy; Anti-Dump strategy; Anti-repackaging strategy; String encryption and decryption strategy. 9. The server of claim 6, wherein: The adding and compiling unit is adapted to write the specified encryption and decryption strategy, the hardening configuration file and the hardening protection program into the SO file under the lib directory of the decompiled APK. 10. A reinforcement protection system for Android applications, comprising: a reinforcement protection client and the reinforcement protection server according to any one of claims 6-9.