WO2007065341A1

WO2007065341A1 - A method and apparatus for verifying an image file

Info

Publication number: WO2007065341A1
Application number: PCT/CN2006/002940
Authority: WO
Inventors: Xiaohu Yang
Original assignee: Tencent Technology (Shenzhen) Company Limited
Priority date: 2005-12-10
Filing date: 2006-11-02
Publication date: 2007-06-14
Also published as: CN100462995C; CN1979516A

Abstract

An image file verification method includes: loading the record including a image file ID and characteristic value; calculating the characteristic value of the image file corresponding the file ID; judging whether the characteristic value recorded in the file match the calculated characteristic value; and if matches, then the verification is passed, otherwise the verification is failed. An image verification apparatus includes: a characteristic value load module, an image file load module, a characteristic value calculating module and a characteristic value comparing module. The technical scheme provided can prevent the image file from being altered arbitrarily.

Description

A method and device for verifying image files Technical field

The present invention relates to image data processing technology, and in particular, to a method and device for verifying image files. Background of the invention

With the development of society and science and technology, image processing technology has been increasingly used in the computer field, making people's work, study and daily life increasingly colorful. In some applications, remote image files need to be downloaded locally before they can be used normally. In this case, the local user may modify the image file, thereby affecting the use of the image file.

For example, in order to increase the personalized effect of the virtual pet game, players can download corresponding image files as props, such as toys, bubble backgrounds, etc., for pets to play with and decorate, so as to increase the fun of adopting pets. In the existing technology, the user first needs to download the image file from the server to the client, and then the user clicks the corresponding item to start the image file on the client, causing the pet to play with the ball or display a bubble background, etc.

Since all image files need to be downloaded to the client before they can be used, users can change the image files at will on the client, causing the pet's personalized effect to be poorly displayed, or affecting the management of image files on the server side. Contents of the invention

In view of this, the present invention provides a method and device for verifying image files, thereby preventing the use of modified image files, thereby preventing the image files from being modified.

A method for verifying image files, including the following steps: Read in records including image file identifiers and feature values;

Calculate the characteristic value of the image file corresponding to the file identification;

Determine whether the characteristic value recorded in the record is the same as the calculated characteristic value. If they are the same, the verification passes, otherwise the verification fails.

A device for documenting image files, including:

The eigenvalue reading module is used to read the eigenvalues from the eigenvalue list and send the read eigenvalues to the eigenvalue comparison module;

The image file reading module is used to read the image file from the directory where the image file is located, and send it to the feature value calculation module;

The feature value calculation module is used to calculate the feature value of the image file according to a predetermined algorithm, and send the calculated feature value to the feature value comparison module;

The eigenvalue comparison module is used to compare whether the eigenvalues sent by the eigenvalue reading module and the eigenvalue calculation module are the same. If they are the same, the output verification passes, otherwise the output verification fails.

According to the technical solution provided by the present invention, when the client downloads the image file locally, it also downloads the feature values of the image file locally. Before using the local image file, compare the characteristic value with the current local image file. If they match, the local image file will be used normally. If they do not match, the file may have been changed or replaced, and the local image file will no longer be used. . This effectively prevents image files from being changed at will. Brief description of the drawings

Figure 1 is a schematic diagram of the use of image files in the embodiment of the present invention.

Figure 2 is a flow chart of using image files in the embodiment of the present invention.

Figure 3 is a flow chart for verifying image files in the embodiment of the present invention.

Figure 4 is a representation of the characteristic value column in the embodiment of the present invention.

Figure 5 is a block diagram of a device for verifying image files in an embodiment of the present invention. Ways to practice the invention

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the drawings and examples. It should be understood that the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

In order to increase the personalized effect of virtual pets, players can download corresponding image files as props, such as toys, bubble backgrounds, etc., for virtual pets to play with and decorate. As shown in Figure 1, in order to display a certain effect, multiple related image files are often required, such as image file 1, image file 2, etc. Therefore, the multiple related image files can be compressed into a file package on the server. The file package includes a feature value list of each related image file generated by the server, where the feature value list is saved in the file. Then the client downloads the file package to the client's pet resource directory; then sets the decompression directory of each image file to the temporary directory of the client system, and then decompresses it on the client. When working with image files, the relevant data is read from the self-extracting directory. Of course, how to set the decompression directory of the image file can be flexibly changed, and is not limited by the present invention.

The specific process when the client of the present invention uses image files will be described below in conjunction with Figure 2:

Step 10, the client detects whether the required image file has been downloaded. If it has been downloaded, go to step 20, otherwise go to step 30.

Step 20, the client verifies the image file. If the verification passes, step 50 is executed, otherwise step 30 is executed.

Step 30, download the required image file, and also download the feature values of the image file.

Here, if what needs to be downloaded is multiple image files, what is downloaded may be a file package including the multiple image files, and the file package further includes a feature value list corresponding to the multiple image files. The feature value list may be encrypted or unencrypted. Step 40, set the decompression directory of the image file, and then decompress the image file.

In step 30, if the image file is not downloaded in the form of a compressed file package, then step 40 can be omitted.

Step 50, read relevant data from the self-extracting directory and use image files.

In step 30, if the image file is not downloaded in the form of a compressed file package, then the decompression directory here should be the download directory.

In a preferred embodiment of the present invention, the feature value list is a HASH value list. Each record of the HASH value list includes a file identifier and a HASH value. There is a "" correspondence between the file identifier and the HASH value. The HASH value is calculated using the MD5 encryption algorithm. The MD5 encryption algorithm can convert data of any length into a fixed-length data string. Once the content of the file changes, the calculated data string will change accordingly. . The HASH value described in turn is equivalent to taking a "snapshot" of the image file, thus recording the original content of the image file.

The following will illustrate how to implement step 20, which is to verify the image file, as shown in Figure 3. Step 201, set the verification directory to the directory where the image file is located. According to step 50, the directory where the image file is located can be the decompression directory or the download directory. Of course, these two directories can also be the same directory. Here, without loss of generality, assuming that the directory where the image file is located is the decompression directory, and the image file is multiple image files, then there are features corresponding to the multiple image files in the directory where the image file is located. List of values.

Step 202: Decrypt the file containing the characteristic value list. If the decryption is successful, perform step 203. Otherwise, it is determined that the verification fails.

If the characteristic value list file downloaded in step 30 is unencrypted, this step can be omitted.

Step 203, read in the feature value list.

Step 204, take out a record from the feature value list. Step 205: Determine whether there is a file corresponding to the file identifier of the record in the verification directory. If it exists, perform step 206. Otherwise, it is determined that the verification has failed.

Step 206: Calculate the current feature value of the corresponding file.

Step 207: Determine whether the characteristic value in the record is equal to the current characteristic value calculated in step 206. If they are equal, perform step 208; otherwise, it is determined that the verification has failed.

'Step 208, determine whether the records in the feature value list have been verified. If so, the verification is completed. Otherwise, return to step 204 and continue reading the next record.

During the above steps, if the decryption of the feature value list fails, or the file corresponding to the verified record does not exist in the verification directory, or the feature value of the corresponding file calculated by the client is different from the feature value list If the values are not equal, the verification will fail and step 30 will be reached directly to start re-downloading the image file instead of using the image file in the current client.

In order to describe the image file verification method of the present invention more clearly, a more detailed description will be given below using the "personalized bubble background image file" in the virtual pet as an example.

A bubble background generally includes three files: "background GIF file", "button BMP file", and "configuration file". For the convenience of downloading, compress the above three files into one file package and download it to the pet resource directory of the client, then set its decompression directory to the temporary directory of the client system, and decompress the three files. The file package also includes a HASH list. As shown in Figure 4, the HASH list includes three records, corresponding to the background, button and configuration file. Each record corresponds to a 16-byte information string, which is a HASH value.

Before using the image file, the client first sets the verification directory as the temporary directory of the client system; decrypts the HASH list; then removes the record corresponding to the background record from the list; verifies the decompression directory in the client system Whether there is a file corresponding to the record, that is, a "background file"; if so, use the MD5 algorithm to calculate the HASH value of the current "background file"; then determine whether the HASH value in the list is consistent with the currently calculated HASH The values are the same; and so on, until the HASH values of all records in the HASH list are the same as the currently calculated HASH values, the verification is passed. If one of the records fails the verification, the bubble background that has been downloaded in this client cannot be used again, and the image file needs to be downloaded again.

To sum up, before each use of an image file, the client must use the encrypted HASH value to compare with all file contents under the current image file. Once a difference is found, it means that the image file has been replaced or changed. The current file will no longer be used and the image file will be downloaded again. This effectively prevents image files from being modified at will.

In order to implement the above method, the present invention also provides a device for verifying image files, including the following modules:

The eigenvalue reading module is used to read eigenvalues from the eigenvalue list, and send the read eigenvalues to the eigenvalue comparison module.

The characteristic value reading module includes a decryption sub-module and a record identification sub-module. The decryption sub-module is used to decrypt the feature value list. If the decryption is successful, the decrypted feature value list is sent to the record identification sub-module. If the decryption fails, it indicates that the feature value comparison module output verification failed; the record identification sub-module is used to Read the record from the feature value list and determine whether there is a file corresponding to the record. If it exists, send the feature value in the record to the feature value comparison module. Otherwise, indicate that the feature value comparison module output verification failed. The decryption submodule is optional.

The image file reading module is used to read the image file from the directory where the image file is located, and send it to the feature value calculation module.

The feature value calculation module is used to calculate the feature value of the image file according to a predetermined algorithm, and send the calculated feature value to the feature value comparison module.

In short, the above descriptions are only preferred embodiments of the present invention and are not intended to limit the scope of the present invention. clear scope of protection. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

claims

1. A method for verifying image files, characterized by including the following steps: reading records including image file identifiers and feature values;

2. The method according to claim 1, characterized in that the characteristic value is a HASH value.

3. The method according to claim 1 or 2, characterized in that, calculating the characteristic value of the image file corresponding to the file identification is:

The MD5 algorithm is used to calculate the feature value of the image file corresponding to the file identification.

4. The method according to claim 1, characterized in that, before reading the record including the image file identifier and the characteristic value, the step further includes:

Decrypt the file containing the record, and if the decryption is successful, read the record; otherwise, it is determined that the verification fails.

5. The method according to claim 1, characterized in that, between the reading of the image file identifier and the recording of the characteristic value and the calculation of the characteristic value of the image file corresponding to the file identifier further includes:

Determine whether there is an image file corresponding to the file identification, and if so, calculate the feature value of the image file; otherwise, determine that the verification has failed.

6. A device for verifying image files, characterized in that the device includes: a feature value reading module, used to read feature values from the feature value list, and send the read feature values to the feature value comparison module ;

Image file reading module, used to read image files from the directory where the image files are located, And sent to the eigenvalue calculation module;

7. The device according to claim 6, characterized in that the characteristic value reading module includes:

The decryption sub-module is used to decrypt the feature value list. If the decryption is successful, the decrypted feature value list will be sent to the record identification sub-module. If the decryption fails, it will indicate that the feature value comparison module output verification failed;

Record identification submodule, used to read records from the feature value list, determine whether there is a file corresponding to the record, and if so, send the feature value in the record to the feature value comparison module, otherwise instruct the feature value comparison module to output verification failed.