WO2016127516A1

WO2016127516A1 - File signature method for operating system, file check method, and apparatus

Info

Publication number: WO2016127516A1
Application number: PCT/CN2015/078902
Authority: WO
Inventors: 张敏; 冉小凯; 刘翔
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-02-13
Filing date: 2015-05-13
Publication date: 2016-08-18
Also published as: CN105989306A; CN105989306B

Abstract

A file signature method for an operating system, a file check method, and an apparatus. The file check method comprises: acquiring mirror files of an operating system (S400); acquiring a signature policy file and a private key file (S500); performing digital signature and encryption on a file matching a condition in the mirror files according to the signature policy file and the private key file, so as to obtain a secure mirror file (S600); acquiring a check signature policy file and a public key file (S700); and checking the secure mirror file according to the check signature policy file and the public key file, and if a check condition is satisfied, considering a file of the operating system secure (S800). Only a file recorded in a check signature policy file is checked, and accordingly the check efficiency is improved; a file digital signature is directly placed in a file attribute entry of a checked file, and the file is accessed and signature information is read after a system is started, and accordingly convenience is brought; a system file can be prevented being tampered with, and a single file or multiple files can be upgraded.

Description

File signature method of operating system, file verification method and device

Technical field

The present invention relates to the field of smart device security technologies, and in particular, to a file signature method, a file verification method, and an apparatus of an operating system.

Background technique

The current intelligent setting of operating systems, such as Android, security events emerge one after another, one of the main reasons is that the contents or attributes of the system's key files have been tampered with. There are two ways to tamper with, one is runtime tampering, that is, executing a crack tool on the running operating system, forcibly modifying the specified file in memory or on disk. The other is that the operating system of the device performs tampering in the case of non-operation, and directly modifies the disk file. At this time, since the operating system of the device is not operating normally, the security protection capability is relatively weak, which gives the cracker a chance to take advantage of it.

The existing disk image tamper-resistant patent literature includes: "A method and apparatus for data tamper resistance" refers to determining whether the modification operation of the determined protected data by the first application program is determined by the operating system kernel according to a pre-saved security policy. For legal operation. However, the shortcoming of this method is that it is impossible to verify that the file mirror on the disk or FLASH is falsified in the non-operational state of the device. The implementation principle of "system startup verification method, system startup verification device and terminal", "OPTIMIZED STARTUP VERIFICATION OF FILE SYSTEM INTEGRITY" and "system for system file integrity verification in system boot area" determines their verification method. In this case, the verification behavior can only occur during the boot start period of the device. The software tamper-proof verification method and apparatus refers to a verification method for comparing a file check value with a server-side check value. However, the shortcoming of this method is that there is a dependence on the network speed. When the network conditions are not good, or when the number of files to be verified is huge and the verification is frequent, the verification efficiency of the method will be very low. .

"INTELLIGENT MOBILE TERMINAL AND DATA PROCESSING METHOD THEREFOR" introduces a signature library and a filtering module. The files accessed by all processors are signed and signed by the signature library. The signature inventory is placed in the hidden partition, and the signature of the accessed file does not exist or If the signature is incorrect, the CPU will first access the file through the filter module. The insufficiency of the invention lies in the obvious performance problem. Generally, the number of file system files of the operating system is very large, and if each has a signature stored in the signature library, it will consume a large space, and the system is Each file is verified by signature, which will seriously slow down the booting of the operating system and reduce the user experience. "Methods for Image File Validation in Run" mentions that a file image is digitally signed to form a new file image, which can be started or started at device startup. After the timing to verify the digital signature of the file image, to achieve tamper-proof effect. The insufficiency of the invention is that the file mirror can only be verified as a whole, and the content of the image file cannot be selectively verified, and the current file mirror is generally large, such as several hundred megabytes, so that the verification efficiency is Very problematic.

Summary of the invention

The technical problem to be solved at least in the embodiments of the present invention is to provide a file signature method, a file verification method, and an apparatus for an operating system, and complete verification of key files by using a signature policy file and a verification policy file to avoid all The verification of the file improves the verification efficiency.

In order to solve at least the above technical problem, the embodiment of the present invention adopts the following technical solutions:

According to an embodiment of the present invention, a method for file signature of an operating system includes: acquiring an image file of an operating system; acquiring a signature policy file and a private key file; and according to the signature policy file and the private key file, The qualified files in the image file are digitally signed and encrypted to obtain a security image file.

Optionally, the obtaining an image file of the operating system includes: acquiring an operating system source file; compiling the operating system source file to generate the image file.

Optionally, the private key file is an asymmetric password private key file.

Optionally, the digitally signing and encrypting the qualified file in the image file according to the signature policy file and the private key file, and obtaining the security image file includes: obtaining a directory in the signature policy file; determining An image file corresponding to the directory in the signature policy file in the image file; the image file is signed and encrypted to obtain the security image file.

Optionally, the step of performing the signing and encryption processing on the image file, the step of obtaining the security image file includes: acquiring a first hash value corresponding to the file content of the image file corresponding to the directory in the signature policy file; Encrypting the first hash value according to the private key file, and saving the encrypted first hash value to a first attribute entry of a file attribute of the image file; acquiring the signature policy a second hash value corresponding to the file attribute of the image file corresponding to the directory in the file; encrypting the second hash value according to the private key file, and saving the encrypted second hash value The security image file is obtained in a second attribute entry of a file attribute of the image file.

Optionally, the file signing method further includes: obtaining an update file corresponding to the file that needs to be upgraded in the operating system; and digitally signing the update file to obtain an upgrade package.

Optionally, the digitally signing the update file to obtain an upgrade package includes: acquiring a first hash value corresponding to the file content of the update file and a second hash corresponding to the file attribute of the update file And storing the first hash value, the second hash value, the file name and the file path of the file that needs to be upgraded corresponding to the update file into the upgrade information file; and acquiring the file of the upgrade information file a hash value corresponding to the content, and encrypting the hash value according to the private key file, saving the encryption result to the upgrade information file; and packaging the update file and the upgrade information file to obtain the upgrade package.

According to still another embodiment of the present invention, a file verification method of an operating system is provided, including: acquiring an image file of an operating system; acquiring a signature policy file and a private key file; and according to the signature policy file and the private key a file, digitally signing and encrypting the qualified file in the image file to obtain a security image file; obtaining a calibration policy file and a public key file; and performing the security image according to the calibration policy file and the public key file The file is verified. If the verification condition is met, the file of the operating system is considered to be secure.

Optionally, the step of performing the signing and encryption processing on the image file, the step of obtaining the security image file includes: acquiring a first hash value corresponding to the file content of the image file corresponding to the directory in the signature policy file; Encrypting the first hash value according to the private key file, and saving the encrypted first hash value to a first attribute entry of a file attribute of the image file; acquiring the signature policy a second hash value corresponding to the file attribute of the image file corresponding to the directory in the file; encrypting the second hash value according to the private key file, and saving the encrypted second hash value to the The security image file is obtained from the second attribute entry of the file attribute of the image file.

Optionally, the step of verifying the security image file according to the calibration policy file and the public key file, and if the verification condition is met, determining that the file security of the operating system is: acquiring the Querying a directory in the policy file; determining a security image file corresponding to the directory in the verification policy file in the security image file; and obtaining a file attribute of the security image file corresponding to the directory in the verification policy file Corresponding second hash value; decrypting, according to the public key file, a second hash value in a second attribute entry of the security image file corresponding to the directory in the calibration policy file; And the second hash value corresponding to the file attribute of the security image file corresponding to the directory in the calibration policy file is the same, according to the public key file, Decrypting the first hash value in the first attribute entry of the security image file corresponding to the directory in the policy file; obtaining a security image corresponding to the directory in the calibration policy file File content corresponding to a first hash value; comparing by the first decrypting the key file with the hash value correction If the first hash value corresponding to the file content of the security image file corresponding to the directory in the policy file is the same, the file of the operating system is considered to be secure.

Optionally, the file verification method further includes: obtaining an update file corresponding to the file that needs to be upgraded in the operating system; performing digital signature on the update file to obtain an upgrade package; and verifying the upgrade package, If the verification condition is met, replace the files that need to be upgraded with the files in the upgrade package.

Optionally, the verifying the upgrade package, if the verification condition is met, replacing the file to be upgraded with the file in the upgrade package includes: obtaining an upgrade information file in the upgrade package a hash value corresponding to the file content; decrypting a hash value corresponding to the file content of the upgrade information file in the upgrade package according to the public key file; comparing the hash value after decryption by the public key file Obtaining a hash value corresponding to the file content of the upgrade information file, if the same, according to the upgrade package, replacing the file corresponding to the update file in the operating system by using the update file in the upgrade package, and The first hash value and the second hash value of the update file in the upgrade information file are respectively saved into the first attribute entry and the second attribute entry of the update file.

According to still another embodiment of the present invention, a file signing apparatus of an operating system is provided, including: a first obtaining module configured to acquire an image file of an operating system; and a second obtaining module configured to obtain a signature policy file and The private key file is configured to digitally sign and encrypt the qualified file in the image file according to the signature policy file and the private key file to obtain a security image file.

According to still another embodiment of the present invention, a file verification apparatus for an operating system is provided, including: a third acquisition module configured to acquire an image file of an operating system; and a fourth acquisition module configured to acquire a signature policy file And a private key file; the second signature module is configured to digitally sign and encrypt the qualified file in the image file according to the signature policy file and the private key file to obtain a security image file; and the fifth obtaining module, setting To obtain the calibration policy file and the public key file, the calibration module is configured to verify the security image file according to the calibration policy file and the public key file, and if the verification condition is met, the operation is considered as System file security.

The beneficial effects of the embodiments of the present invention include at least: the embodiment of the present invention signs the key files in the image file by using the signature policy file, avoids checking all the files, and improves the verification efficiency; in addition, directly storing the digital signature of the file In the file attribute entry of the verified file, it is very convenient to read the signature information while accessing the file after the system is started, which saves the CPU expenditure of reading the extra signature file during the verification in the general method, and the verification efficiency is greatly improved. The embodiment of the invention can prevent the system file from being tampered with, and can also upgrade a single file or multiple files. The upgrade mode is also verified to ensure the security problem of the system upgrade, and the security is improved under the premise of ensuring security. The user experience reduces the maintenance cost of the system upgrade.

DRAWINGS

1 is a schematic diagram of a file signature method of an operating system according to an embodiment of the present invention;

2 is a schematic diagram of a file verification method of an operating system according to an embodiment of the present invention;

FIG. 3 is a flowchart showing a practical application of a file signature method of an operating system according to an embodiment of the present invention;

4 is a flowchart showing a practical application of a file verification method of an operating system according to an embodiment of the present invention;

FIG. 5 is a flowchart showing an actual application process of a file verification method of an operating system according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a file signature device of an operating system according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a file verification apparatus of an operating system according to an embodiment of the present invention.

detailed description

The present invention will be described in detail below with reference to the drawings and specific embodiments.

As shown in FIG. 1 , a schematic diagram of a file signature method of an operating system according to an embodiment of the present invention includes the following steps:

Step S100: Obtain an image file of the operating system.

Here, the image file of the operating system is generated by compiling the server to compile the source file.

Step S200: Obtain a signature policy file and a private key file.

Here, the signature policy file is written by the user according to the specified syntax, including the name or feature of a series of files to be verified, and the file matching the file name or feature in the signature policy file is signed, and the private key file is an asymmetric password. The private key file is obtained by the prior art, for example, by using the RSA 1024 algorithm in a cryptographic algorithm such as openSSL, where the directory of the signature policy file contains its own file name.

Step S300: Perform digital signature and encryption on the qualified file in the image file according to the signature policy file and the private key file to obtain a security image file.

Here, the directory in the signature policy file has a file that needs to be digitally signed, and the image file is digitally signed according to the directory, and the signature is obtained by calculating a hash value corresponding to the file content of the image file, and the hash value is The hash value is encrypted by the private key file, and the encrypted hash value is saved to the file attribute of the image file, wherein the file attribute further includes an extended attribute. Specifically, the first attribute item is created in the file attribute to save the encryption. After the hash value; calculate the hash value corresponding to all the file attributes of the image file, and encrypt the hash value through the private key file, and save the encrypted hash value to the second attribute entry of the image file. Preferably, the hash values in the first attribute entry and the second attribute entry are encrypted using different private key files.

When the operating system is upgraded, in order to avoid errors during file verification, first determine the files that are changed before and after the upgrade, and digitally sign the update files corresponding to the files that need to be upgraded in the operating system, where the digital signature method and the signature policy file are The methods for digitally signing files in the directory are the same and will not be described here.

FIG. 2 is a schematic diagram of a file verification method of an operating system according to an embodiment of the present invention, including the following steps:

Step S400: Obtain an image file of the operating system.

Step S500: Obtain a signature policy file and a private key file.

Step S600: Perform digital signature and encryption on the qualified file in the image file according to the signature policy file and the private key file to obtain a security image file.

Step S700: Obtain a calibration policy file and a public key file.

Here, the directory in the verification policy file is the same as the directory in the signature policy file, and the public key file corresponds to the private key file, and the hash value encrypted by the private key file may be decrypted.

In step S800, the security image file is verified according to the verification policy file and the public key file, and if the verification condition is met, the file of the operating system is considered to be secure.

Here, the directory in the verification policy file has a file to be verified, and the image file is digitally signed according to the directory, wherein the directory of the verification policy file contains its own file name, and the verification is performed by the following steps: :

Step S810: Obtain a directory in the calibration policy file.

Step S820: Determine a security image file corresponding to the directory in the verification policy file in the security image file.

Step S830: Acquire a second hash value corresponding to the file attribute of the security image file corresponding to the directory in the calibration policy file.

Step S840: Decrypt the second hash value in the second attribute entry of the security image file corresponding to the directory in the verification policy file according to the public key file.

Step S850: Comparing the second hash value after decrypting the public key file with the second hash value corresponding to the file attribute of the security image file corresponding to the directory in the verification policy file, if the same, according to the public key file, The first hash value in the first attribute entry of the security image file corresponding to the directory in the policy file is decrypted.

Step S860: Acquire a first hash value corresponding to the file content of the security image file corresponding to the directory in the calibration policy file.

Step S870: Comparing the first hash value after the decryption of the public key file with the first hash value corresponding to the file content of the security image file corresponding to the directory in the verification policy file, if the same, the security image file is considered to be secure.

Here, when the operating system is upgraded, in order to avoid errors during file verification, first determine the files that are changed before and after the upgrade, digitally sign the update files corresponding to the files that need to be upgraded in the operating system, and name the signature information and update files. And the path is saved to the upgrade information file, and then the hash value corresponding to the file content of the upgrade information file is calculated, the hash value is encrypted, and the encryption result is also saved to the upgrade information file. Whether the information file exists and has been tampered with. If the file is upgraded after verification, the signature information of the update file is queried according to the file name and path of the update file, and the signature information obtained by the query is saved to the file attribute of the update file. The embodiment of the invention can prevent the system file from being tampered with, and can also upgrade a single file or multiple files. The upgrade mode is also verified to ensure the security problem of the system upgrade. Moreover, the user experience is improved under the premise of ensuring security, and the maintenance cost of the system upgrade is reduced.

In the embodiment of the present invention, the key file in the image file is signed by the signature policy file to avoid verification of all the files, and the verification efficiency is improved; further, the digital signature of the file is directly stored in the file attribute entry of the verified file. It is very convenient to read the signature information while accessing the file after the system is started, which saves the CPU expenditure of reading the extra signature file in the general method during the verification, and the verification efficiency is greatly improved.

As shown in FIG. 3, a practical application flowchart of a file signature method of an operating system according to an embodiment of the present invention includes the following steps:

Step 301: The compiled operating system image file is delivered to the file signature and injection tool. Specifically, the compile server completes the source code compilation, and the system file partition generates the system.img image file in the ext4 format. The file signature and injection tool is an executable program, which is responsible for scanning all file names and attributes in the operating system image file, and comparing signatures. The signature condition in the policy file, digitally sign the eligible file.

Step 302: The file signature and the injection tool mount the image file, and the user creates a signature policy file and a private key file of the asymmetric password according to the requirements of the user, and submits the file to the file signature and injection tool. Specifically, the signature policy file includes all files whose username is root. The private key file of the asymmetric password is a public-private key pair that generates a set of asymmetric passwords by running the openssl public method on the compile server. The encryption algorithm uses RSA 1024.

Step 303, the file signature and the injection tool sequentially scan and analyze the contents of the file in the image file that is hung.

Step 304: Whether the file name or attribute meets the conditions described in the signature policy file.

Step 305, ignoring no processing to continue scanning the next file.

Step 306: Calculate a hash value of the file content and encrypt it with a private key, and the encryption result is written into the first attribute entry of the attribute node corresponding to the file.

Step 307: Calculate a hash value of all attributes including the first attribute item, encrypt it with a private key, and write the encrypted result into the second attribute item of the corresponding attribute node of the file.

Step 308: After the file is scanned, the signature policy file is also digitally signed and saved in the file attribute entry.

Step 309: Unmount the image file, and the image file of the original operating system has been injected and converted into a security image file.

As shown in FIG. 4, a flowchart of a practical application of a file verification method of an operating system according to an embodiment of the present invention includes the following steps:

Step 401: The system is powered on, the firmware of the device, and the boot initiator are first started, and the booting of the operating system kernel is started.

Step 402: After the kernel is started, the calibration execution tool is first run, and the calibration execution tool obtains a public key or a digital certificate file and a signature policy file from the read-only root partition of the kernel, and performs signature verification of the signature policy file. Specifically, the proof execution tool is an executable program that can be run independently and stored in a secure read-only partition of the system. By modifying the system's init.rc file, the proof execution tool can be executed first when the system is booted. .

Step 403: Whether the signature of the signature policy file itself is passed.

Step 404, the verification fails, the kernel stops booting, and performs a predefined security protection behavior, such as popping a security warning on the user interface.

Step 405: The operating system kernel runs normally, and the signed system image file and the user image file are mounted, and the system file partition of the signed operating system and the user data partition of the signed operating system are generated.

Step 406: The calibration execution tool scans the mounted system files and all file names and file attributes in the user data partition.

Step 407, whether the file name or file attribute meets the conditions in the proof policy file.

Step 408: The file does not belong to the verification range, and ignores, and continues to scan the next file.

Step 409: The digital signature saved by the second attribute entry is used to check whether the file information is falsified; the specific calibration execution tool queries the file attribute entry of the file to be checked, including the extended attribute item that may exist, if the existing The second attribute entry calculates the total hash value of the file attributes other than the second attribute entry. Compared with the hash value of the second attribute entry after the digital signature is decrypted by the public key or the digital certificate file, if the inconsistency, the file is considered to be less than the signature; if yes, the process proceeds to step 410.

Step 410: The digital signature saved by the first attribute entry is used to check whether the file information is falsified; the specific calibration execution tool queries the file attribute entry of the file to be checked, including the extended attribute item that may exist, and whether the query exists. The first attribute entry, if present, calculates a total hash value of the file content of the file, and compares the hash value after the digital signature in the first attribute entry is decrypted by the public key or the digital certificate file, and if not, the file is considered as a file The signing failed; if it is consistent, the file attribute information is not falsified.

Step 411: The file verification fails at startup, and refuses to continue to execute the predefined security protection behavior, for example, a security warning pops up on the user interface.

Step 412, the file verification is passed, the system continues to boot, and the kernel driver needs to perform real-time verification every time after opening or running the file.

In step 413, the real-time verification of the file is passed.

Step 414: Perform a predefined security protection behavior, and the kernel may refuse to open or execute the file, or may choose to record the verification failure in the log.

Step 415, the file is normally opened or executed.

As shown in FIG. 5, the flowchart of the actual application of the file verification method of the operating system provided by the embodiment of the present invention includes the following steps:

Step 501: Compare the file list with differences before and after the upgrade to the file signature and injection tool, and sequentially scan all the files in the upgrade package.

Step 502: Whether it belongs to a file that needs to be upgraded and signed.

In step 503, the file is ignored and the next file is scanned. Specifically, if the user re-compiles the source code of the system as needed, the files A and B in the re-compiled image are modified, and the files A and B can be detected through steps 501-503.

Step 504, file signature and injection tool, digitally sign the file by referring to step 306 and step 307 in FIG. Specifically, the files A and B in the upgrade package are digitally signed instead of the files A and B in the original system.

Step 505: The file signature and injection tool calculates a digital digest for the upgrade information file and encrypts the digital signature information by using a private key file of the asymmetric password, saves the signature information at the end of the upgrade information file, and then merges the upgrade information file into the system upgrade package. Repackaged in.

Step 506: The device to be upgraded is powered on, and the firmware and the boot initiator of the device are first started, and the kernel that carries the operating system upgrade function is booted.

Step 507: The kernel reads the system upgrade package, verifies the integrity of the upgrade package, and then searches for the upgrade information file, and verifies the digital signature of the file with the public key. The specific kernel with upgrade function reads the system upgrade package, verifies the integrity of the system upgrade package, and then extracts the upgrade information file from the file, obtains the digital signature information from the content of the upgrade information file, and upgrades with the public key or digital certificate file. The digital signature at the end of the information file is compared. If the upgrade information file does not exist or the license is not passed, the kernel should terminate the upgrade process, alert the user with the alarm screen, or adopt other customized security protection actions.

Step 508: Whether the upgrade information file exists and if the verification is passed.

Step 509: The kernel terminates the upgrade process and performs a predefined security protection behavior, such as popping a security warning on the user interface.

Step 510: The kernel with the upgrade function expands the system upgrade package, and the file in the upgrade package is replaced with the copy of the source file on the device to be upgraded, and the upgrade operation is completed.

The embodiment of the invention can prevent the system file from being tampered with, and can also upgrade a single file or multiple files. The upgrade mode is also verified to ensure the security problem of the system upgrade, and the user is improved under the premise of ensuring security. The experience reduces the maintenance cost of the system upgrade.

As shown in FIG. 6, the embodiment of the present invention further provides a schematic diagram of a file signing device of an operating system, including: a first obtaining module 61 configured to acquire an image file of an operating system; and a second obtaining module 62 configured to obtain a signature The policy file and the private key file; the first signature module 63 is configured to digitally sign and encrypt the qualified file in the image file according to the signature policy file and the private key file to obtain a security image file.

It should be noted that the device is a device corresponding to the file signature method of the operating system. All the implementation manners in the foregoing method embodiments are applicable to the device embodiment, and the same technical effects can be achieved.

As shown in FIG. 7 , an embodiment of the present invention further provides a file verification device of an operating system, including: a third obtaining module 71 configured to acquire an image file of an operating system; and a fourth obtaining module 72 configured to acquire a signature policy file and a private key file; the second signature module 73 is configured to digitally sign and encrypt the qualified file in the image file according to the signature policy file and the private key file to obtain a security image file; and the fifth obtaining module 74. Set to obtain the calibration policy file and the public key file; the calibration module 75 is configured to verify the security image file according to the verification policy file and the public key file, and if the verification condition is met, the operating system is considered File security.

The above is a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and refinements without departing from the principles of the present invention. These improvements and refinements are also within the scope of the present invention. Inside.

Industrial applicability

As described above, the file signature method, the file verification method, and the device of the operating system provided by the embodiments of the present invention have the following beneficial effects: the embodiment of the present invention signs a key file in the image file by using a signature policy file to avoid The verification of all files improves the verification efficiency; in addition, the digital signature of the file is directly stored in the file attribute entry of the verified file, and it is convenient to read the signature information while accessing the file after the system is started, saving the general In the method, the CPU cost of the extra signature file is read during the verification, and the verification efficiency is greatly improved. The embodiment of the invention can prevent the system file from being tampered with, and can also upgrade the single or multiple files. After verification, the security of the system upgrade is guaranteed, and the user experience is improved under the premise of ensuring security, and the maintenance cost of the system upgrade is reduced.

Claims

A file signing method for an operating system, including:

Obtain an image file of the operating system;

Obtain a signature policy file and a private key file;

And performing, according to the signature policy file and the private key file, digitally signing and encrypting the qualified file in the image file to obtain a security image file.
The file signing method of claim 1, wherein the obtaining an image file of the operating system comprises:

Obtain the operating system source file;

The operating system source file is compiled to generate the image file.
The file signing method of claim 1, wherein the private key file is an asymmetric cipher private key file.
The file signing method according to claim 1, wherein the digitally signing and encrypting the qualified file in the image file according to the signature policy file and the private key file, and obtaining the security image file includes:

Obtaining a directory in the signature policy file;

Determining, in the image file, an image file corresponding to the directory in the signature policy file;

The image file is signed and encrypted to obtain the security image file.
The file signing method according to claim 4, wherein the step of signing and encrypting the image file to obtain the security image file comprises:

Obtaining a first hash value corresponding to the file content of the image file corresponding to the directory in the signature policy file;

Encrypting the first hash value according to the private key file, and saving the encrypted first hash value to a first attribute entry of a file attribute of the image file;

Obtaining a second hash value corresponding to a file attribute of the image file corresponding to the directory in the signature policy file;

Encrypting the second hash value according to the private key file, and saving the encrypted second hash value to a second attribute entry of a file attribute of the image file to obtain the security Image file.
The file signing method according to claim 1, wherein the file signing method further comprises:

Obtain an update file corresponding to the file that needs to be upgraded in the operating system;

The update file is digitally signed to obtain an upgrade package.
The file signing method according to claim 6, wherein the digitally signing the update file to obtain an upgrade package comprises:

Obtaining a first hash value corresponding to the file content of the update file and a second hash value corresponding to the file attribute of the update file;

Saving the first hash value, the second hash value, the file name and the file path of the file to be upgraded corresponding to the update file into the upgrade information file;

Obtaining a hash value corresponding to the file content of the upgrade information file, and encrypting the hash value according to the private key file, and saving the encryption result to the upgrade information file;

The update file and the upgrade information file are packaged to obtain the upgrade package.
An operating system file verification method includes:

Obtain an image file of the operating system;

Obtain a signature policy file and a private key file;

Performing a digital signature and encryption on the qualified file in the image file according to the signature policy file and the private key file to obtain a security image file;

Obtain the proofing strategy file and the public key file;

The security image file is verified according to the verification policy file and the public key file, and if the verification condition is met, the file of the operating system is considered to be secure.
The file verification method according to claim 8, wherein the digitally signing and encrypting the qualified file in the image file according to the signature policy file and the private key file, and obtaining the security image file includes:

Obtaining a directory in the signature policy file;

Determining, in the image file, an image file corresponding to the directory in the signature policy file;

The image file is signed and encrypted to obtain the security image file.
The file verification method according to claim 9, wherein the step of signing and encrypting the image file to obtain the security image file comprises:

Obtaining a first hash value corresponding to the file content of the image file corresponding to the directory in the signature policy file;

Encrypting the first hash value according to the private key file, and saving the encrypted first hash value to a first attribute entry of a file attribute of the image file;

Obtaining a second hash value corresponding to a file attribute of the image file corresponding to the directory in the signature policy file;

Encrypting the second hash value according to the private key file, and saving the encrypted second hash value to a second attribute entry of a file attribute of the image file to obtain the security image file .
The file verification method according to claim 10, wherein the security image file is verified according to the calibration policy file and the public key file, and if the verification condition is met, the operating system is considered The steps for file security include:

Obtaining a directory in the proof policy file;

Determining, in the security image file, a security image file corresponding to the directory in the calibration policy file;

Obtaining a second hash value corresponding to a file attribute of the security image file corresponding to the directory in the calibration policy file;

Decrypting the second hash value in the second attribute entry of the security image file corresponding to the directory in the calibration policy file according to the public key file;

And comparing, according to the second hash value that is decrypted by the public key file, a second hash value corresponding to a file attribute of the security image file corresponding to the directory in the calibration policy file, if the same, according to the public key a file, where the first hash value in the first attribute entry of the security image file corresponding to the directory in the calibration policy file is decrypted;

Obtaining a first hash value corresponding to the file content of the security image file corresponding to the directory in the calibration policy file;

Comparing, by the first hash value after the decryption of the public key file, the first hash value corresponding to the file content of the security image file corresponding to the directory in the calibration policy file, if the same, the operating system is considered File security.
The file verification method according to claim 8, wherein the file verification method further comprises:

Obtain an update file corresponding to the file that needs to be upgraded in the operating system;

Digitally signing the update file to obtain an upgrade package;

The upgrade package is verified. If the verification condition is met, the file to be upgraded is replaced with the file in the upgrade package.
The file verification method according to claim 12, wherein said digitally signing said update file to obtain an upgrade package comprises:

Obtaining a first hash value corresponding to the file content of the update file and a second hash value corresponding to the file attribute of the update file;

Saving the first hash value, the second hash value, the file name and the file path of the file to be upgraded corresponding to the update file into the upgrade information file;

Obtaining a hash value corresponding to the file content of the upgrade information file, and encrypting the hash value according to the private key file, and saving the encryption result to the upgrade information file;

The update file and the upgrade information file are packaged to obtain the upgrade package.
The file verification method according to claim 13, wherein the verifying the upgrade package, if the verification condition is met, replacing the file to be upgraded with the file in the upgrade package includes:

Obtaining a hash value corresponding to the file content of the upgrade information file in the upgrade package;

Decrypting a hash value corresponding to the file content of the upgrade information file in the upgrade package according to the public key file;

Comparing the hash value after the decrypted by the public key file with the obtained hash value of the file content of the upgrade information file, if the same, according to the upgrade package, replacing the operation by using the update file in the upgrade package a file corresponding to the update file in the system, and saving the first hash value and the second hash value of the update file in the upgrade information file to the first attribute item and the second attribute of the update file, respectively In the entry.
The file verification method according to claim 8, wherein the obtaining an image file of the operating system comprises:

Obtain the operating system source file;

The operating system source file is compiled to generate the image file.
A file signing device for an operating system, comprising:

The first obtaining module is configured to obtain an image file of the operating system;

a second obtaining module, configured to obtain a signature policy file and a private key file;

The first signature module is configured to digitally sign and encrypt the qualified file in the image file according to the signature policy file and the private key file to obtain a security image file.
A file verification device for an operating system, comprising:

The third obtaining module is configured to obtain an image file of the operating system;

a fourth obtaining module, configured to obtain a signature policy file and a private key file;

The second signature module is configured to digitally sign and encrypt the qualified file in the image file according to the signature policy file and the private key file to obtain a security image file;

The fifth obtaining module is configured to obtain the calibration policy file and the public key file;

The verification module is configured to verify the security image file according to the verification policy file and the public key file, and if the verification condition is met, the file of the operating system is considered to be secure.