# Data File Security Strategy and Implementation Based on Fuzzy Control Algorithm

Authors: Jin Ren
Journal: Security and Communication Networks
 (2022)

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## Abstract

Today there are few studies on data file security strategies, but with the increase in information technology, the more the security of data files cannot be ignored. In this paper, based on the research of data file security policy, a model of data file security interaction based on a fuzzy control algorithm is proposed, and the correct rate of the model proposed in this paper is improved by about 1.5% under the traditional FTP server-based model.


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## Body

## 1. Introduction

In today’s information era, the use of computers has greatly facilitated people’s lives and changed their office and communication methods. Computer data security refers to the adoption of certain technical measures to provide shelter and security protection for computer data information to ensure that it will not be lost or stolen or damaged due to negligence or accidental reasons. A data file is a file that stores data information on a computer, and there are many types of data files, including XML, DAT, which are the two most common types of data files. DAT data file format is a more general file format and can be opened or used by any application, so it is the most widely used. XML data file format is often used for code extensions by programmers and can therefore be called Extensible Markup Language. XML data file format is mainly used to store programming languages in the form of JAVA, C, C++, etc. It is similar to HTML, but XML files are used to store and transfer data and structures over the Internet.Also, in the era of “Internet+,” information security and data security are getting more and more attention. Data file security can be expressed in two ways: firstly, it refers to the security of the data and the data file itself; secondly, it refers to the protection of the data and the data file. In today’s data, file security does not have a precise definition but generally refers to the security of data files on the computer and the risk of data leakage and data packet loss due to threats to data files in the process of transmission.Essentially, a data file is a file that can store any data information, generally using a binary file format. Moreover, data files should be system files created by computer operating systems or application data files created by applications, or human-created data files, including types such as project files, libraries, or documents. However, due to the development of science and technology nowadays, information security is also threatened by people with wrong intentions, and people are more and more concerned about the security of data information. In order to protect the security of data files, many scholars have presented their insights and analysis. For example, Kun Wang and Yanjun Lu proposed to put data file security control technology, which is researched and implemented mainly by imposing filters on the creation, use, and editing of documents through file filtering-driven technology and protecting the contents of important documents by using transparent encryption and decryption technology. Through the study of various data file control technologies, we provide users with technical support and an overall data file security strategy [1].


## 2. Security Risks of Data Files

### 2.1. Data File Security Issues

With the advent of the era of big data, technological advances, the complexity of today’s Internet environment, and various types of data processing activities, this paper will analyze the security of data files and risky causes based on the scientific analysis of the threats and security issues facing people’s computer data files at this stage, and on this basis, put forward targeted data file security governance strategies for the traditional data file security. The advantages and disadvantages of traditional data file security technologies such as protection management and transmission risks are analyzed. Among them, the security of data files is mainly caused by the following factors (Figure1).Figure 1
Risk factors of data security.


#### 2.1.1. Data File Usage Environment

First of all, the security of data files is analyzed in terms of the environment in which they are used. The environment of data files is mainly composed of the production environment, development and testing environment, office environment, and Internet environment [1]. When people in different environments use the same data file, the data file needs to be transferred and shared for processing, and data security risks will inevitably arise when the data file is circulated in different environments. In the production environment, it refers to the general running production system, business application system with high concurrent access links, and the data file contains a large amount of sensitive information, and the main data security risks are the lack of active interception of batch export and the lack of audit records [2]. In the development and testing environment, the completion of a system or a software and hardware development requires different developers for data development, and the data for development and testing are generally innovative and authentic data, and all the testers involved in the development can access the development data files, making the threat of data security greatly increased [3]. In the office environment, the main data security threats are the lack of active interception of batch export behavior and the inability to supervise operation and maintenance operations. As most of the data in the office environment are financial data, customer information data, production plan data, and business report data, illegal elements will do anything to get these data, making the risk of data file security in the office environment much higher [4]. In the Internet environment, due to a large number of branches of large enterprises, the need to share data transmission makes illegal elements frequently attack the transmission path of their data files or directly intercept the network during transmission in order to threaten such companies or to obtain important secrets of such companies and sell them to others for profit. Therefore, in the Internet environment, the threat to data security cannot be ignored, and the slightest mistake may cause irreparable damage to a company or group of companies.


#### 2.1.2. Unauthorized Access and Data Theft

In addition to the threat to data file security posed by the data usage environment, unauthorized access is also an important threat factor that cannot be ignored. Unauthorized access refers to the bad behavior of copying, pasting, modifying, or destroying data files of computers without the consent of computer users [2]. In the era of big data today, the value of data has attracted people’s attention, and most people think that data is private and has its value and significance, especially for scientific research results, but there are some unscrupulous people who have evil intentions to get the computer data files, thus using some technical means to cross the administrator’s management authority to delete, modify, copy, and do other operations on other people’s computer data files [5]. In order to get the computer data files, some unscrupulous people use some technical means to transgress the administrator’s management rights and delete, modify, copy, and do other operations on other people’s computer data files, thus causing the leakage of data and theft of scientific research results [6]. Unauthorized access generally has the following forms: the first is to impersonate administrators or users, invade other people’s computers, obtain access rights, and use illegal means to plagiarize other people’s data files; the second is to control and enter other people’s computers through network attacks, copy, delete, and modify scientific research results or directly delete important system data files inside computers. The second is to control and access other people’s computers through network attacks, to copy, delete, modify scientific research results, or directly delete important system data files inside the computer, resulting in the leakage or theft of data files, as well as direct virus invasion of the computer, resulting in the computer no longer being used, and naturally, the data files inside the computer cannot be accessed and modified, copied, etc.


#### 2.1.3. Data Corruption

Data corruption refers to the subjective and malicious damage to the data itself, resulting in the unavailability of computer data files or the loss of important files, which affects the use of the computer. There are many reasons for data corruption, the most important of which is the damage caused by virus infection to data files, followed by “hacking” programs or software bundles, software bugs, and other reasons to cause damage to data files [7]. Some computer viruses are usually hidden, sometimes even through the security manager, and other antivirus software cannot be detected. This kind of hidden computer viruses, after the invasion of the computer, can get all the rights to use the computer, can manipulate the computer’s data files at will, delete, copy, or modify at will.


#### 2.1.4. Data Loss

For individuals, the loss of data can cause many adverse consequences, such as the risk of privacy exposure if the data files are lost; secondly, if the data files related to personal preferences are lost or “targeted” by businesses, it can greatly affect the quality of life of individuals, such as businesses to promote their products or software to promote a certain product, always pushing some promotional information or phone calls, SMS bombing, seriously affecting life. For enterprises, the loss of critical data will be incalculable. Relevant studies show that global enterprises lose $1.7 trillion due to downtime or loss of critical data files. This is only the monetary loss; there is also the loss of hidden assets, such as business processing, business activity interruption, loss of customer loyalty, funds for reallocation of resources, production suffers stagnation and investor confidence, etc., which will have a long-term impact on the company [8].


#### 2.1.5. Operator Misconduct

Firstly, when using important data files with passwords, due to the handover of data files to multiple parties, it may cause the error of improper use of passwords, which may lead to the phenomenon of data files being locked after repeatedly entering wrong passwords; secondly, some staff members are not familiar enough with computers, improperly using antivirus software or directly and unintentionally The firewall is closed, and the computer with insufficient protection is unable to prevent the invasion of viruses, thus contaminating the data files of the computer; thirdly, the intranet uses computers for illegal outreach. Some scientific research institutions or enterprises with strong confidentiality may require the use of an intranet to test and develop data files, but if the operator does not operate properly and mistakenly uses the external network, it will lead to the risk of leakage of key data files; finally, the use of bad email or data sharing by external operators does not use the regular way, resulting in important confidential data files being attacked and intercepted in the process of data transmission, increasing the leakage of data files [9]. The risk of data file leakage is increased by the use of bad emails or the failure of the operator to use formal channels for data sharing.In summary, most of these five types of security issues regarding data files are related to data transmission and data sharing. The security of data files during transmission and download is also related to the packet loss rate, which may cause data leakage. The data loss rate is related to whether the data buffer is overflowing or not. Therefore, in this paper, we consider the use of a fuzzy control algorithm to set the cache and propose a strategy and analysis for the security of data files.


### 2.2. Data File Transfer Techniques and Problems

#### 2.2.1. Data File Transmission Methods

In today’s era of information explosion, it is more and more common to send and receive data files over 1 GB in size, such as images taken by photographers using DSLR cameras can reach several tens of MB, but the memory occupied by the video is almost 1 DB in size. For multinational companies, the transfer of data files with large data volumes has become a daily requirement, and now that data has become an important production resource, the improvement and enhancement of transmission methods and distribution technologies for massive data have become a goal to be pursued [10].So, how are large files transferred in daily life? What are the common transmission technologies?First of all, HTTP, i.e., Hypertext Transfer, is a classic distribution transfer method that mainly uses the bandwidth and storage of the server to transfer and distribute files, but the HTTP link between the client and the server is a one-time connection, i.e., the connection will be closed automatically each time the server returns an answer to a request [11].As shown in Figure2, the HTTP-based file transfer mode has four main steps: first, the client establishes a connection with the server; second, the client makes a request to the server for data file transfer after the connection is established; third, the server responds with an answer and returns the data file; then the server and client automatically close the connection, completing the entire process of the data file transfer.Figure 2
Typical HTTP transaction processing principle of operation.Next is FTP mode, that is, File Transfer Protocol, abbreviated as “File Protocol,” mainly used for two-way transmission on the Internet, is a file distribution method similar to HTTP [12]. FTP is an application layer protocol based on C/S architecture, and the underlying application is TCP/IP protocol to ensure the reliability of transmission. The block diagram of FTP mode in the process of data file transfer is shown in Figure 3.Figure 3
Block diagram of FTP mode working principle.As can be seen from Figure3, FTP makes it possible to share data files between service hosts and between servers and clients, which is essentially copying files back and forth between two hosts [13]. The basic process of FTP is firstly, establishing a connection, secondly, transferring data and releasing data, and finally, releasing the connection [14]. Observing Figure 3, we can see that there are two types of connections in FTP mode, namely data connection and control connection, so there are two ports between FTP server and client, one for transferring commands and one for transferring data. This design method is mainly to solve the problem that the FTP server has less control information but a large amount of data.Finally, there is the data file transfer method for software classes such as QQ, mail, and Baidu.com. With a large number of QQ users, the main function of QQ is to exchange and communicate, so QQ is only suitable for transferring data files less than 1 GB. If it exceeds 1 GB, then the transfer rate will become particularly slow; even though QQ now supports data file transfer in offline mode, it is always easy to cause data transfer interruption and other phenomena when transferring large files for various reasons [15]. For emails, it is also a common way to transfer data files, but it takes the form of attachments for transferring, and the size of the attachments is generally 10–30 MB. If the emails are transferred with larger attachments, the successful transfer of the emails may not be guaranteed due to the other party’s server and network stability, and if the other party does not receive the files in time, the files will expire. This is because the file transfer station of emails has a certain time limit. For this kind of software, the main function of Baidu.com is cloud storage, which can also meet the needs of people in daily life, such as document management, photo storage, and data file transfer. It is because the main function of Baidu.com is to store data, so it has a large storage space and supports file classification and browsing and multiplatform data sharing, but its shortcomings are also obvious, such as downloading and uploading data files at a limited speed, only a few dozen k a second if not open super members, which is difficult to meet people’s requirements for timely and lightweight data file transfer [16].


#### 2.2.2. Analysis of Advantages and Disadvantages of HTTP and FTP Transmission

In the previous subsection, three data file transfer methods were discussed, and since the software class belongs to the data file transfer method on the application, this paper does not explore them [17]. But what are the advantages and disadvantages of HTTP and FTP data file transfer methods?First is the HTTP mode. HTTP mode is mainly a protocol way to transfer data through direct networking. There are four common methods of the HTTP protocol, namely GET method, POST method, PUT method, and DELETE method. The GET method is designed to obtain a resource on the server and is one of the earliest methods proposed by most HTTP protocols. GET method, after requesting data information attached to the server’s interface, will start with “?” splitting the URT and the transmitted data, for multiple parameters will use “&” connection, but the amount of data transmitted by this method is limited by the length of the URL and is only suitable for small amounts of data transmission [18]. However, for the POST method, in theory, the size of the transmitted data realized by this method is not limited; for the PUT method, it is generally used to modify the URL resource. If the URL resource does not exist, the server will request the corresponding URL resource according to the request. If the resource exists, it will request to modify the original URL [6] resource. The DELETE method corresponds to the English “delete,” which means requesting the server to delete a specific resource [19].The reliability of data file transfer based on HTTP protocol is high because HTTP protocol is based on TCP protocol for data transfer. However, because HTTP protocol is a plaintext transmission protocol, there is no encryption in the process of data file interaction, so the security of HTTP protocol is poor. Its plaintext transmission protocol makes data files in the transmission process with a risk of data file exposure and leakage.Next is the FTP protocol [20]. FTP has no limitation on file size and is relatively simple to operate. However, when the volume of data files is large, the speed will become slower and the problem of data transmission interruption will easily occur, resulting in data transmission errors. Moreover, the FTP server also transmits data in clear text, which poses a threat to security. In addition, FTP also lacks sufficient control functions, such as the lack of audit function, there is no way to judge and guarantee the compliance of the sent data, and the flow of data is also uncontrollable, which may cause the risk of data leakage for the transmission of data files [21]. What’s more, the use of an FTP server may lead to problems such as poor traceability of data files. This is due to the characteristics of FTP, which is limited in its ability to trace file transfers.As we can see from the above discussion, both HTTP protocol and FTP server exchange data in clear text form for data file transfer, using the “request + response” model. Most of websites nowadays use the less secure HTTP protocol, which may cause packet loss due to the difference in the acceptance rate of both computers’ file systems when the data file transfer is too large. For this problem of FTP server, it is necessary to set cache area between the client and server of data file transfer to automatically deal with the problem of packet loss when data files interact or the failure of saving due to unknown data lines, etc. Based on this, a data file security strategy based on a fuzzy control algorithm is proposed and analyzed, and implemented through experiments [22].


## 2.1. Data File Security Issues

With the advent of the era of big data, technological advances, the complexity of today’s Internet environment, and various types of data processing activities, this paper will analyze the security of data files and risky causes based on the scientific analysis of the threats and security issues facing people’s computer data files at this stage, and on this basis, put forward targeted data file security governance strategies for the traditional data file security. The advantages and disadvantages of traditional data file security technologies such as protection management and transmission risks are analyzed. Among them, the security of data files is mainly caused by the following factors (Figure1).Figure 1
Risk factors of data security.


### 2.1.1. Data File Usage Environment

First of all, the security of data files is analyzed in terms of the environment in which they are used. The environment of data files is mainly composed of the production environment, development and testing environment, office environment, and Internet environment [1]. When people in different environments use the same data file, the data file needs to be transferred and shared for processing, and data security risks will inevitably arise when the data file is circulated in different environments. In the production environment, it refers to the general running production system, business application system with high concurrent access links, and the data file contains a large amount of sensitive information, and the main data security risks are the lack of active interception of batch export and the lack of audit records [2]. In the development and testing environment, the completion of a system or a software and hardware development requires different developers for data development, and the data for development and testing are generally innovative and authentic data, and all the testers involved in the development can access the development data files, making the threat of data security greatly increased [3]. In the office environment, the main data security threats are the lack of active interception of batch export behavior and the inability to supervise operation and maintenance operations. As most of the data in the office environment are financial data, customer information data, production plan data, and business report data, illegal elements will do anything to get these data, making the risk of data file security in the office environment much higher [4]. In the Internet environment, due to a large number of branches of large enterprises, the need to share data transmission makes illegal elements frequently attack the transmission path of their data files or directly intercept the network during transmission in order to threaten such companies or to obtain important secrets of such companies and sell them to others for profit. Therefore, in the Internet environment, the threat to data security cannot be ignored, and the slightest mistake may cause irreparable damage to a company or group of companies.


### 2.1.2. Unauthorized Access and Data Theft

In addition to the threat to data file security posed by the data usage environment, unauthorized access is also an important threat factor that cannot be ignored. Unauthorized access refers to the bad behavior of copying, pasting, modifying, or destroying data files of computers without the consent of computer users [2]. In the era of big data today, the value of data has attracted people’s attention, and most people think that data is private and has its value and significance, especially for scientific research results, but there are some unscrupulous people who have evil intentions to get the computer data files, thus using some technical means to cross the administrator’s management authority to delete, modify, copy, and do other operations on other people’s computer data files [5]. In order to get the computer data files, some unscrupulous people use some technical means to transgress the administrator’s management rights and delete, modify, copy, and do other operations on other people’s computer data files, thus causing the leakage of data and theft of scientific research results [6]. Unauthorized access generally has the following forms: the first is to impersonate administrators or users, invade other people’s computers, obtain access rights, and use illegal means to plagiarize other people’s data files; the second is to control and enter other people’s computers through network attacks, copy, delete, and modify scientific research results or directly delete important system data files inside computers. The second is to control and access other people’s computers through network attacks, to copy, delete, modify scientific research results, or directly delete important system data files inside the computer, resulting in the leakage or theft of data files, as well as direct virus invasion of the computer, resulting in the computer no longer being used, and naturally, the data files inside the computer cannot be accessed and modified, copied, etc.


### 2.1.3. Data Corruption

Data corruption refers to the subjective and malicious damage to the data itself, resulting in the unavailability of computer data files or the loss of important files, which affects the use of the computer. There are many reasons for data corruption, the most important of which is the damage caused by virus infection to data files, followed by “hacking” programs or software bundles, software bugs, and other reasons to cause damage to data files [7]. Some computer viruses are usually hidden, sometimes even through the security manager, and other antivirus software cannot be detected. This kind of hidden computer viruses, after the invasion of the computer, can get all the rights to use the computer, can manipulate the computer’s data files at will, delete, copy, or modify at will.


### 2.1.4. Data Loss

For individuals, the loss of data can cause many adverse consequences, such as the risk of privacy exposure if the data files are lost; secondly, if the data files related to personal preferences are lost or “targeted” by businesses, it can greatly affect the quality of life of individuals, such as businesses to promote their products or software to promote a certain product, always pushing some promotional information or phone calls, SMS bombing, seriously affecting life. For enterprises, the loss of critical data will be incalculable. Relevant studies show that global enterprises lose $1.7 trillion due to downtime or loss of critical data files. This is only the monetary loss; there is also the loss of hidden assets, such as business processing, business activity interruption, loss of customer loyalty, funds for reallocation of resources, production suffers stagnation and investor confidence, etc., which will have a long-term impact on the company [8].


### 2.1.5. Operator Misconduct

Firstly, when using important data files with passwords, due to the handover of data files to multiple parties, it may cause the error of improper use of passwords, which may lead to the phenomenon of data files being locked after repeatedly entering wrong passwords; secondly, some staff members are not familiar enough with computers, improperly using antivirus software or directly and unintentionally The firewall is closed, and the computer with insufficient protection is unable to prevent the invasion of viruses, thus contaminating the data files of the computer; thirdly, the intranet uses computers for illegal outreach. Some scientific research institutions or enterprises with strong confidentiality may require the use of an intranet to test and develop data files, but if the operator does not operate properly and mistakenly uses the external network, it will lead to the risk of leakage of key data files; finally, the use of bad email or data sharing by external operators does not use the regular way, resulting in important confidential data files being attacked and intercepted in the process of data transmission, increasing the leakage of data files [9]. The risk of data file leakage is increased by the use of bad emails or the failure of the operator to use formal channels for data sharing.In summary, most of these five types of security issues regarding data files are related to data transmission and data sharing. The security of data files during transmission and download is also related to the packet loss rate, which may cause data leakage. The data loss rate is related to whether the data buffer is overflowing or not. Therefore, in this paper, we consider the use of a fuzzy control algorithm to set the cache and propose a strategy and analysis for the security of data files.


## 2.1.1. Data File Usage Environment

First of all, the security of data files is analyzed in terms of the environment in which they are used. The environment of data files is mainly composed of the production environment, development and testing environment, office environment, and Internet environment [1]. When people in different environments use the same data file, the data file needs to be transferred and shared for processing, and data security risks will inevitably arise when the data file is circulated in different environments. In the production environment, it refers to the general running production system, business application system with high concurrent access links, and the data file contains a large amount of sensitive information, and the main data security risks are the lack of active interception of batch export and the lack of audit records [2]. In the development and testing environment, the completion of a system or a software and hardware development requires different developers for data development, and the data for development and testing are generally innovative and authentic data, and all the testers involved in the development can access the development data files, making the threat of data security greatly increased [3]. In the office environment, the main data security threats are the lack of active interception of batch export behavior and the inability to supervise operation and maintenance operations. As most of the data in the office environment are financial data, customer information data, production plan data, and business report data, illegal elements will do anything to get these data, making the risk of data file security in the office environment much higher [4]. In the Internet environment, due to a large number of branches of large enterprises, the need to share data transmission makes illegal elements frequently attack the transmission path of their data files or directly intercept the network during transmission in order to threaten such companies or to obtain important secrets of such companies and sell them to others for profit. Therefore, in the Internet environment, the threat to data security cannot be ignored, and the slightest mistake may cause irreparable damage to a company or group of companies.


## 2.1.2. Unauthorized Access and Data Theft

In addition to the threat to data file security posed by the data usage environment, unauthorized access is also an important threat factor that cannot be ignored. Unauthorized access refers to the bad behavior of copying, pasting, modifying, or destroying data files of computers without the consent of computer users [2]. In the era of big data today, the value of data has attracted people’s attention, and most people think that data is private and has its value and significance, especially for scientific research results, but there are some unscrupulous people who have evil intentions to get the computer data files, thus using some technical means to cross the administrator’s management authority to delete, modify, copy, and do other operations on other people’s computer data files [5]. In order to get the computer data files, some unscrupulous people use some technical means to transgress the administrator’s management rights and delete, modify, copy, and do other operations on other people’s computer data files, thus causing the leakage of data and theft of scientific research results [6]. Unauthorized access generally has the following forms: the first is to impersonate administrators or users, invade other people’s computers, obtain access rights, and use illegal means to plagiarize other people’s data files; the second is to control and enter other people’s computers through network attacks, copy, delete, and modify scientific research results or directly delete important system data files inside computers. The second is to control and access other people’s computers through network attacks, to copy, delete, modify scientific research results, or directly delete important system data files inside the computer, resulting in the leakage or theft of data files, as well as direct virus invasion of the computer, resulting in the computer no longer being used, and naturally, the data files inside the computer cannot be accessed and modified, copied, etc.


## 2.1.3. Data Corruption

Data corruption refers to the subjective and malicious damage to the data itself, resulting in the unavailability of computer data files or the loss of important files, which affects the use of the computer. There are many reasons for data corruption, the most important of which is the damage caused by virus infection to data files, followed by “hacking” programs or software bundles, software bugs, and other reasons to cause damage to data files [7]. Some computer viruses are usually hidden, sometimes even through the security manager, and other antivirus software cannot be detected. This kind of hidden computer viruses, after the invasion of the computer, can get all the rights to use the computer, can manipulate the computer’s data files at will, delete, copy, or modify at will.


## 2.1.4. Data Loss

For individuals, the loss of data can cause many adverse consequences, such as the risk of privacy exposure if the data files are lost; secondly, if the data files related to personal preferences are lost or “targeted” by businesses, it can greatly affect the quality of life of individuals, such as businesses to promote their products or software to promote a certain product, always pushing some promotional information or phone calls, SMS bombing, seriously affecting life. For enterprises, the loss of critical data will be incalculable. Relevant studies show that global enterprises lose $1.7 trillion due to downtime or loss of critical data files. This is only the monetary loss; there is also the loss of hidden assets, such as business processing, business activity interruption, loss of customer loyalty, funds for reallocation of resources, production suffers stagnation and investor confidence, etc., which will have a long-term impact on the company [8].


## 2.1.5. Operator Misconduct

Firstly, when using important data files with passwords, due to the handover of data files to multiple parties, it may cause the error of improper use of passwords, which may lead to the phenomenon of data files being locked after repeatedly entering wrong passwords; secondly, some staff members are not familiar enough with computers, improperly using antivirus software or directly and unintentionally The firewall is closed, and the computer with insufficient protection is unable to prevent the invasion of viruses, thus contaminating the data files of the computer; thirdly, the intranet uses computers for illegal outreach. Some scientific research institutions or enterprises with strong confidentiality may require the use of an intranet to test and develop data files, but if the operator does not operate properly and mistakenly uses the external network, it will lead to the risk of leakage of key data files; finally, the use of bad email or data sharing by external operators does not use the regular way, resulting in important confidential data files being attacked and intercepted in the process of data transmission, increasing the leakage of data files [9]. The risk of data file leakage is increased by the use of bad emails or the failure of the operator to use formal channels for data sharing.In summary, most of these five types of security issues regarding data files are related to data transmission and data sharing. The security of data files during transmission and download is also related to the packet loss rate, which may cause data leakage. The data loss rate is related to whether the data buffer is overflowing or not. Therefore, in this paper, we consider the use of a fuzzy control algorithm to set the cache and propose a strategy and analysis for the security of data files.


## 2.2. Data File Transfer Techniques and Problems

### 2.2.1. Data File Transmission Methods

In today’s era of information explosion, it is more and more common to send and receive data files over 1 GB in size, such as images taken by photographers using DSLR cameras can reach several tens of MB, but the memory occupied by the video is almost 1 DB in size. For multinational companies, the transfer of data files with large data volumes has become a daily requirement, and now that data has become an important production resource, the improvement and enhancement of transmission methods and distribution technologies for massive data have become a goal to be pursued [10].So, how are large files transferred in daily life? What are the common transmission technologies?First of all, HTTP, i.e., Hypertext Transfer, is a classic distribution transfer method that mainly uses the bandwidth and storage of the server to transfer and distribute files, but the HTTP link between the client and the server is a one-time connection, i.e., the connection will be closed automatically each time the server returns an answer to a request [11].As shown in Figure2, the HTTP-based file transfer mode has four main steps: first, the client establishes a connection with the server; second, the client makes a request to the server for data file transfer after the connection is established; third, the server responds with an answer and returns the data file; then the server and client automatically close the connection, completing the entire process of the data file transfer.Figure 2
Typical HTTP transaction processing principle of operation.Next is FTP mode, that is, File Transfer Protocol, abbreviated as “File Protocol,” mainly used for two-way transmission on the Internet, is a file distribution method similar to HTTP [12]. FTP is an application layer protocol based on C/S architecture, and the underlying application is TCP/IP protocol to ensure the reliability of transmission. The block diagram of FTP mode in the process of data file transfer is shown in Figure 3.Figure 3
Block diagram of FTP mode working principle.As can be seen from Figure3, FTP makes it possible to share data files between service hosts and between servers and clients, which is essentially copying files back and forth between two hosts [13]. The basic process of FTP is firstly, establishing a connection, secondly, transferring data and releasing data, and finally, releasing the connection [14]. Observing Figure 3, we can see that there are two types of connections in FTP mode, namely data connection and control connection, so there are two ports between FTP server and client, one for transferring commands and one for transferring data. This design method is mainly to solve the problem that the FTP server has less control information but a large amount of data.Finally, there is the data file transfer method for software classes such as QQ, mail, and Baidu.com. With a large number of QQ users, the main function of QQ is to exchange and communicate, so QQ is only suitable for transferring data files less than 1 GB. If it exceeds 1 GB, then the transfer rate will become particularly slow; even though QQ now supports data file transfer in offline mode, it is always easy to cause data transfer interruption and other phenomena when transferring large files for various reasons [15]. For emails, it is also a common way to transfer data files, but it takes the form of attachments for transferring, and the size of the attachments is generally 10–30 MB. If the emails are transferred with larger attachments, the successful transfer of the emails may not be guaranteed due to the other party’s server and network stability, and if the other party does not receive the files in time, the files will expire. This is because the file transfer station of emails has a certain time limit. For this kind of software, the main function of Baidu.com is cloud storage, which can also meet the needs of people in daily life, such as document management, photo storage, and data file transfer. It is because the main function of Baidu.com is to store data, so it has a large storage space and supports file classification and browsing and multiplatform data sharing, but its shortcomings are also obvious, such as downloading and uploading data files at a limited speed, only a few dozen k a second if not open super members, which is difficult to meet people’s requirements for timely and lightweight data file transfer [16].


### 2.2.2. Analysis of Advantages and Disadvantages of HTTP and FTP Transmission

In the previous subsection, three data file transfer methods were discussed, and since the software class belongs to the data file transfer method on the application, this paper does not explore them [17]. But what are the advantages and disadvantages of HTTP and FTP data file transfer methods?First is the HTTP mode. HTTP mode is mainly a protocol way to transfer data through direct networking. There are four common methods of the HTTP protocol, namely GET method, POST method, PUT method, and DELETE method. The GET method is designed to obtain a resource on the server and is one of the earliest methods proposed by most HTTP protocols. GET method, after requesting data information attached to the server’s interface, will start with “?” splitting the URT and the transmitted data, for multiple parameters will use “&” connection, but the amount of data transmitted by this method is limited by the length of the URL and is only suitable for small amounts of data transmission [18]. However, for the POST method, in theory, the size of the transmitted data realized by this method is not limited; for the PUT method, it is generally used to modify the URL resource. If the URL resource does not exist, the server will request the corresponding URL resource according to the request. If the resource exists, it will request to modify the original URL [6] resource. The DELETE method corresponds to the English “delete,” which means requesting the server to delete a specific resource [19].The reliability of data file transfer based on HTTP protocol is high because HTTP protocol is based on TCP protocol for data transfer. However, because HTTP protocol is a plaintext transmission protocol, there is no encryption in the process of data file interaction, so the security of HTTP protocol is poor. Its plaintext transmission protocol makes data files in the transmission process with a risk of data file exposure and leakage.Next is the FTP protocol [20]. FTP has no limitation on file size and is relatively simple to operate. However, when the volume of data files is large, the speed will become slower and the problem of data transmission interruption will easily occur, resulting in data transmission errors. Moreover, the FTP server also transmits data in clear text, which poses a threat to security. In addition, FTP also lacks sufficient control functions, such as the lack of audit function, there is no way to judge and guarantee the compliance of the sent data, and the flow of data is also uncontrollable, which may cause the risk of data leakage for the transmission of data files [21]. What’s more, the use of an FTP server may lead to problems such as poor traceability of data files. This is due to the characteristics of FTP, which is limited in its ability to trace file transfers.As we can see from the above discussion, both HTTP protocol and FTP server exchange data in clear text form for data file transfer, using the “request + response” model. Most of websites nowadays use the less secure HTTP protocol, which may cause packet loss due to the difference in the acceptance rate of both computers’ file systems when the data file transfer is too large. For this problem of FTP server, it is necessary to set cache area between the client and server of data file transfer to automatically deal with the problem of packet loss when data files interact or the failure of saving due to unknown data lines, etc. Based on this, a data file security strategy based on a fuzzy control algorithm is proposed and analyzed, and implemented through experiments [22].


## 2.2.1. Data File Transmission Methods

In today’s era of information explosion, it is more and more common to send and receive data files over 1 GB in size, such as images taken by photographers using DSLR cameras can reach several tens of MB, but the memory occupied by the video is almost 1 DB in size. For multinational companies, the transfer of data files with large data volumes has become a daily requirement, and now that data has become an important production resource, the improvement and enhancement of transmission methods and distribution technologies for massive data have become a goal to be pursued [10].So, how are large files transferred in daily life? What are the common transmission technologies?First of all, HTTP, i.e., Hypertext Transfer, is a classic distribution transfer method that mainly uses the bandwidth and storage of the server to transfer and distribute files, but the HTTP link between the client and the server is a one-time connection, i.e., the connection will be closed automatically each time the server returns an answer to a request [11].As shown in Figure2, the HTTP-based file transfer mode has four main steps: first, the client establishes a connection with the server; second, the client makes a request to the server for data file transfer after the connection is established; third, the server responds with an answer and returns the data file; then the server and client automatically close the connection, completing the entire process of the data file transfer.Figure 2
Typical HTTP transaction processing principle of operation.Next is FTP mode, that is, File Transfer Protocol, abbreviated as “File Protocol,” mainly used for two-way transmission on the Internet, is a file distribution method similar to HTTP [12]. FTP is an application layer protocol based on C/S architecture, and the underlying application is TCP/IP protocol to ensure the reliability of transmission. The block diagram of FTP mode in the process of data file transfer is shown in Figure 3.Figure 3
Block diagram of FTP mode working principle.As can be seen from Figure3, FTP makes it possible to share data files between service hosts and between servers and clients, which is essentially copying files back and forth between two hosts [13]. The basic process of FTP is firstly, establishing a connection, secondly, transferring data and releasing data, and finally, releasing the connection [14]. Observing Figure 3, we can see that there are two types of connections in FTP mode, namely data connection and control connection, so there are two ports between FTP server and client, one for transferring commands and one for transferring data. This design method is mainly to solve the problem that the FTP server has less control information but a large amount of data.Finally, there is the data file transfer method for software classes such as QQ, mail, and Baidu.com. With a large number of QQ users, the main function of QQ is to exchange and communicate, so QQ is only suitable for transferring data files less than 1 GB. If it exceeds 1 GB, then the transfer rate will become particularly slow; even though QQ now supports data file transfer in offline mode, it is always easy to cause data transfer interruption and other phenomena when transferring large files for various reasons [15]. For emails, it is also a common way to transfer data files, but it takes the form of attachments for transferring, and the size of the attachments is generally 10–30 MB. If the emails are transferred with larger attachments, the successful transfer of the emails may not be guaranteed due to the other party’s server and network stability, and if the other party does not receive the files in time, the files will expire. This is because the file transfer station of emails has a certain time limit. For this kind of software, the main function of Baidu.com is cloud storage, which can also meet the needs of people in daily life, such as document management, photo storage, and data file transfer. It is because the main function of Baidu.com is to store data, so it has a large storage space and supports file classification and browsing and multiplatform data sharing, but its shortcomings are also obvious, such as downloading and uploading data files at a limited speed, only a few dozen k a second if not open super members, which is difficult to meet people’s requirements for timely and lightweight data file transfer [16].


## 2.2.2. Analysis of Advantages and Disadvantages of HTTP and FTP Transmission

In the previous subsection, three data file transfer methods were discussed, and since the software class belongs to the data file transfer method on the application, this paper does not explore them [17]. But what are the advantages and disadvantages of HTTP and FTP data file transfer methods?First is the HTTP mode. HTTP mode is mainly a protocol way to transfer data through direct networking. There are four common methods of the HTTP protocol, namely GET method, POST method, PUT method, and DELETE method. The GET method is designed to obtain a resource on the server and is one of the earliest methods proposed by most HTTP protocols. GET method, after requesting data information attached to the server’s interface, will start with “?” splitting the URT and the transmitted data, for multiple parameters will use “&” connection, but the amount of data transmitted by this method is limited by the length of the URL and is only suitable for small amounts of data transmission [18]. However, for the POST method, in theory, the size of the transmitted data realized by this method is not limited; for the PUT method, it is generally used to modify the URL resource. If the URL resource does not exist, the server will request the corresponding URL resource according to the request. If the resource exists, it will request to modify the original URL [6] resource. The DELETE method corresponds to the English “delete,” which means requesting the server to delete a specific resource [19].The reliability of data file transfer based on HTTP protocol is high because HTTP protocol is based on TCP protocol for data transfer. However, because HTTP protocol is a plaintext transmission protocol, there is no encryption in the process of data file interaction, so the security of HTTP protocol is poor. Its plaintext transmission protocol makes data files in the transmission process with a risk of data file exposure and leakage.Next is the FTP protocol [20]. FTP has no limitation on file size and is relatively simple to operate. However, when the volume of data files is large, the speed will become slower and the problem of data transmission interruption will easily occur, resulting in data transmission errors. Moreover, the FTP server also transmits data in clear text, which poses a threat to security. In addition, FTP also lacks sufficient control functions, such as the lack of audit function, there is no way to judge and guarantee the compliance of the sent data, and the flow of data is also uncontrollable, which may cause the risk of data leakage for the transmission of data files [21]. What’s more, the use of an FTP server may lead to problems such as poor traceability of data files. This is due to the characteristics of FTP, which is limited in its ability to trace file transfers.As we can see from the above discussion, both HTTP protocol and FTP server exchange data in clear text form for data file transfer, using the “request + response” model. Most of websites nowadays use the less secure HTTP protocol, which may cause packet loss due to the difference in the acceptance rate of both computers’ file systems when the data file transfer is too large. For this problem of FTP server, it is necessary to set cache area between the client and server of data file transfer to automatically deal with the problem of packet loss when data files interact or the failure of saving due to unknown data lines, etc. Based on this, a data file security strategy based on a fuzzy control algorithm is proposed and analyzed, and implemented through experiments [22].


## 3. Fuzzy Control Algorithm

As we can see from chapters 1 and 2, the security risk of data files is not only related to internal factors but also to external factors, and data file sharing is inevitable regardless of internal and external factors. Since there is a demand for data file sharing, data files are bound to be transferred [23]. In the process of data transfer, both HTTP protocol and FTP protocol used have certain security problems. This paper mainly focuses on the data file sharing and transmission process by proposing the use of a fuzzy control algorithm to increase the cache in the process of data file transfer in order to reduce the packet loss of data files, and at the same time, in order to increase the security and improve the reliability of data files. After that, a data file transmission model is constructed so as to realize the security policy scheme for data files, and a data file security model based on a fuzzy control algorithm is constructed, which has a certain reference value for subsequent research [24].Next, the theoretical part of the fuzzy control algorithm is described in terms of an overview of fuzzy control theory, input and output variables of fuzzy controller, the establishment of fuzzy rules, and fuzzy relations and fuzzy reasoning. One of the general block diagrams of the fuzzy control algorithm is shown in Figure4 [25].Figure 4
Basic block diagram of fuzzy control system.


### 3.1. Overview of Fuzzy Control Theory

In 1965, L.A. Zadeh proposed the fuzzy set theory, which has been widely used and developed since then; in 1973, in order to make the fuzzy set theory more perfect, he also proposed the use of fuzzy linguistic variables to represent the control state of the relevant control variables and achieve effective control of the variables through fuzzy linguistic variables, and in the same year, he also formally proposed the definition of fuzzy control and The theory related to fuzzy control [26].Fuzzy control algorithm, a control strategy method that uses language to generalize the operator, is an intelligent control method based on fuzzy set theory, herding linguistic variables, and fuzzy logic reasoning. The method is based on a priori knowledge, incorporating human experience in a traditional nonlinear system and fuzzifying the obtained rules to compile a set of rule base’s and complete fuzzy inference, followed by fuzzy verdict and finally defuzzification of the signal or data after the verdict is completed using a defuzzifier. This is the basic process of the whole fuzzy control algorithm [27].In the fuzzy control algorithm, the most important feature is that there is no need to establish a precise mathematical model of the controlled object but only to require experts or related technical personnel to use professional knowledge or a priori knowledge to summarize experience and data into more perfect linguistic control rules; therefore, in essence, fuzzy control can also be considered as a kind of expert control, which can fully reflect the activities of human thinking and the process of thought. The core of the fuzzy control algorithm is the fuzzy controller [28].


### 3.2. Input and Output Variables of the Fuzzy Controller

As can be seen from Figure4, the fuzzy controller needs to be generated before it can be used. Generating fuzzy is actually the input variable of the fuzzy controller, and removing fuzzy is the output variable of the fuzzy controller. During the control of the controlled object, three variables are generally used for decision making: the deviation between the set value and the controlled quantity, the deviation change EC, and the rate of deviation change.In fuzzy control, both input and output variables are described in linguistic form, so an appropriate language is selected for the description. This collection of linguistic forms describing the fuzzy can be called a fuzzy set. A prerequisite for a fuzzy controller’s input to be used as output is its fuzzification, which is essentially the conversion of an exact input quantity into a corresponding fuzzy [10] vector.In the fuzzy quantity of a variable, the actual range of variation of a variable becomes the fundamental domain [29]. Obviously, the range of variation in the fundamental domain is the real exact value of the variable, which is required in the fuzzy controller, so the exact quantity needs to be fuzzified. Let the basic theoretical domain of deviation be (−X, X), the basic theoretical domain of deviation change be (−XC, XC), the basic theoretical domain of output variable of fuzzy controller be (−Y, Y), the conversion formula from the basic theoretical domain [a, b] to fuzzy subset theoretical domain is as follows:(1)y=2nb−ax−a+b2.In the vocabulary for describing input and output variables, three levels of words are generally used, such as “fast, medium, slow” for describing speed; however, in practical applications, three words “large, medium, small” are generally chosen to describe the input and output variables of a fuzzy controller [30]. However, in practical application, we generally choose to use “large, medium, and small” to describe the input and output variable states of the fuzzy controller, plus positive, negative, and zero states, which can be expressed in English and Chinese as shown in the following equations:(2)E=negative large,negative medium,negative small,zero,positive small,positive medium,positive large=NB·NM·NS·ZEPSPMPM,(3)E=negative large,negative medium,negative small,positive zero,negative zero,positive small,positive medium,positive large=NB·NM·NS·NO·PO·PS·PM·PB.The terms described in the above equations are not necessarily chosen in full, but can also be chosen less; e.g., the range of error variables expressed in equation (2) is one state less than that of equation (3).


### 3.3. Affiliation Function and Fuzzification

As can be seen from Figure4, the knowledge base is the whole part framed by dashed lines, including two parts, the database and the rule base. The rule base is another linguistic representation of fuzzy reasoning, which is the a priori knowledge derived from the long-term work of experts or other professionals; the database is a collection composed of affiliation vectors. Among them, the affiliation is to achieve fuzzification, i.e., to establish a relationship between the exact quantities discretized in Section 3.2 and the fuzzy quantities representing the fuzzy language, describing the degree to which a variable belongs to the language of a fuzzy variable, which is called the affiliation function in the case of a continuous domain of the argument.The affiliation function, which is mainly designed to reflect the fuzzy character of the fuzzy set, plays a key role in the overall fuzzy [11] controller. When fuzzy control is performed on variables, the first step is to fuzzify them, mainly by applying the affiliation function to the input variables to make the input variables themselves more accurate, but the processed input variables are converted to fuzzy vectors. Therefore, when constructing a fuzzy set, the affiliation function should be selected appropriately so that the variables can be fuzzified reasonably.


### 3.4. Fuzzy Relations and Fuzzy Inference

Fuzzy relationship is a relatively common relationship in nature, except that some fuzzy relationships are difficult to be detected. The fuzzy relationships that exist between things can be described by the degree of association formed by fuzzy theory. This degree of association is usually expressed in the form of a matrix.In fuzzy reasoning, it refers to the process of formulating fuzzy rules for the input variables of a fuzzy control system, combined with the social experience or a priori knowledge of experts or professionals, from which a fuzzy relational equation can be formed, and the final fuzzy control output is obtained. In computer language, it is similar to forming a kind of if-else statement, i.e., if the expression in parentheses is true, the statement is executed; if it is false, the content in the else statement is executed. The key in fuzzy reasoning is to use the relation matrix obtained under fuzzy relations and perform mathematical operations on it so that the fuzzy set can be processed effectively to finally output the output variables of the fuzzy controller.Before the process of fuzzy inference, it is necessary to first construct fuzzy sets and establish a meaningful and complete rule base in the form of affiliation functions of fuzzy sets or other linguistic descriptions of the input variables that can drive the application of fuzzy inference.


### 3.5. Defuzzification

Defuzzification is the final step of a fuzzy controller, which means that the fuzzy values obtained from the previous fuzzy inference are converted to exact values and used as inputs to another control system. There are two commonly used methods in defuzzification, which are the maximum affiliation method and the weighted average judgment method.


## 3.1. Overview of Fuzzy Control Theory

In 1965, L.A. Zadeh proposed the fuzzy set theory, which has been widely used and developed since then; in 1973, in order to make the fuzzy set theory more perfect, he also proposed the use of fuzzy linguistic variables to represent the control state of the relevant control variables and achieve effective control of the variables through fuzzy linguistic variables, and in the same year, he also formally proposed the definition of fuzzy control and The theory related to fuzzy control [26].Fuzzy control algorithm, a control strategy method that uses language to generalize the operator, is an intelligent control method based on fuzzy set theory, herding linguistic variables, and fuzzy logic reasoning. The method is based on a priori knowledge, incorporating human experience in a traditional nonlinear system and fuzzifying the obtained rules to compile a set of rule base’s and complete fuzzy inference, followed by fuzzy verdict and finally defuzzification of the signal or data after the verdict is completed using a defuzzifier. This is the basic process of the whole fuzzy control algorithm [27].In the fuzzy control algorithm, the most important feature is that there is no need to establish a precise mathematical model of the controlled object but only to require experts or related technical personnel to use professional knowledge or a priori knowledge to summarize experience and data into more perfect linguistic control rules; therefore, in essence, fuzzy control can also be considered as a kind of expert control, which can fully reflect the activities of human thinking and the process of thought. The core of the fuzzy control algorithm is the fuzzy controller [28].


## 3.2. Input and Output Variables of the Fuzzy Controller

As can be seen from Figure4, the fuzzy controller needs to be generated before it can be used. Generating fuzzy is actually the input variable of the fuzzy controller, and removing fuzzy is the output variable of the fuzzy controller. During the control of the controlled object, three variables are generally used for decision making: the deviation between the set value and the controlled quantity, the deviation change EC, and the rate of deviation change.In fuzzy control, both input and output variables are described in linguistic form, so an appropriate language is selected for the description. This collection of linguistic forms describing the fuzzy can be called a fuzzy set. A prerequisite for a fuzzy controller’s input to be used as output is its fuzzification, which is essentially the conversion of an exact input quantity into a corresponding fuzzy [10] vector.In the fuzzy quantity of a variable, the actual range of variation of a variable becomes the fundamental domain [29]. Obviously, the range of variation in the fundamental domain is the real exact value of the variable, which is required in the fuzzy controller, so the exact quantity needs to be fuzzified. Let the basic theoretical domain of deviation be (−X, X), the basic theoretical domain of deviation change be (−XC, XC), the basic theoretical domain of output variable of fuzzy controller be (−Y, Y), the conversion formula from the basic theoretical domain [a, b] to fuzzy subset theoretical domain is as follows:(1)y=2nb−ax−a+b2.In the vocabulary for describing input and output variables, three levels of words are generally used, such as “fast, medium, slow” for describing speed; however, in practical applications, three words “large, medium, small” are generally chosen to describe the input and output variables of a fuzzy controller [30]. However, in practical application, we generally choose to use “large, medium, and small” to describe the input and output variable states of the fuzzy controller, plus positive, negative, and zero states, which can be expressed in English and Chinese as shown in the following equations:(2)E=negative large,negative medium,negative small,zero,positive small,positive medium,positive large=NB·NM·NS·ZEPSPMPM,(3)E=negative large,negative medium,negative small,positive zero,negative zero,positive small,positive medium,positive large=NB·NM·NS·NO·PO·PS·PM·PB.The terms described in the above equations are not necessarily chosen in full, but can also be chosen less; e.g., the range of error variables expressed in equation (2) is one state less than that of equation (3).


## 3.3. Affiliation Function and Fuzzification

As can be seen from Figure4, the knowledge base is the whole part framed by dashed lines, including two parts, the database and the rule base. The rule base is another linguistic representation of fuzzy reasoning, which is the a priori knowledge derived from the long-term work of experts or other professionals; the database is a collection composed of affiliation vectors. Among them, the affiliation is to achieve fuzzification, i.e., to establish a relationship between the exact quantities discretized in Section 3.2 and the fuzzy quantities representing the fuzzy language, describing the degree to which a variable belongs to the language of a fuzzy variable, which is called the affiliation function in the case of a continuous domain of the argument.The affiliation function, which is mainly designed to reflect the fuzzy character of the fuzzy set, plays a key role in the overall fuzzy [11] controller. When fuzzy control is performed on variables, the first step is to fuzzify them, mainly by applying the affiliation function to the input variables to make the input variables themselves more accurate, but the processed input variables are converted to fuzzy vectors. Therefore, when constructing a fuzzy set, the affiliation function should be selected appropriately so that the variables can be fuzzified reasonably.


## 3.4. Fuzzy Relations and Fuzzy Inference

Fuzzy relationship is a relatively common relationship in nature, except that some fuzzy relationships are difficult to be detected. The fuzzy relationships that exist between things can be described by the degree of association formed by fuzzy theory. This degree of association is usually expressed in the form of a matrix.In fuzzy reasoning, it refers to the process of formulating fuzzy rules for the input variables of a fuzzy control system, combined with the social experience or a priori knowledge of experts or professionals, from which a fuzzy relational equation can be formed, and the final fuzzy control output is obtained. In computer language, it is similar to forming a kind of if-else statement, i.e., if the expression in parentheses is true, the statement is executed; if it is false, the content in the else statement is executed. The key in fuzzy reasoning is to use the relation matrix obtained under fuzzy relations and perform mathematical operations on it so that the fuzzy set can be processed effectively to finally output the output variables of the fuzzy controller.Before the process of fuzzy inference, it is necessary to first construct fuzzy sets and establish a meaningful and complete rule base in the form of affiliation functions of fuzzy sets or other linguistic descriptions of the input variables that can drive the application of fuzzy inference.


## 3.5. Defuzzification

Defuzzification is the final step of a fuzzy controller, which means that the fuzzy values obtained from the previous fuzzy inference are converted to exact values and used as inputs to another control system. There are two commonly used methods in defuzzification, which are the maximum affiliation method and the weighted average judgment method.


## 4. Fuzzy Control Based Data File Security Policy Scheme

### 4.1. Basic Implementation of ftp Server

There are two ways to connect FTP. One is the connection of control command, i.e., the connection between client and server; one is the connection of data transfer, and the FTP service program generally supports two different working modes, which are passive (passive) mode and active (port) mode. The connections in both of these modes are shown Figures5 and 6.Figure 5
Control connection and data connection in port mode.Figure 6
Control connection and data connection in passive mode.In active mode, FTP runs on ports 20 and 21, where port 20 is mainly used for data flow transfer between the client and the server, and port 21 is mainly used for transferring commands for interaction between the client and the server. In active mode, the client firstly requests a control connection to port 21 of the server, secondly sends port commands to the server through port 21 on the connection, and finally, the FTP server transfers data files through the data connection port indicated by the port command. Since port mode has specified that port 20 and port 21 must be used, to establish the development of FTP server data file transfer, the passive mode must be used, which works as shown in Figure6.In the passive mode, the biggest difference from the active mode is that its server control port is 21, but the data port is a random port larger than 1024. Therefore, in the passive mode, the data port of the client has to actively connect to the data port of the server, whose data port is random.


### 4.2. General Framework of Data File Security Policy under Fuzzy Control

First of all, the analysis of data security problems shows that most data files have the risk of data leakage problems related to the transmission or sharing of data files, so this paper mainly focuses on the data security problem when data files are transmitted and shared under the study of data file security policy. Based on the analysis and discussion in the previous section, data files are generally transmitted using software-based and protocol-based methods. Since there is no specific research significance for software-based data file transmission, this paper focuses on a new model for the secure transmission of protocol-based data files.The first 3 sections analyze the advantages and disadvantages of HTTP and FTP and get the conclusion that both of them use plaintext transmission and have problems such as poor security and confidentiality. Since HTTP protocol is mostly a data file transfer on a browser, and an FTP server is essentially a “copy” of data files between two computers, this paper studies the construction of a security policy for data file transfer using an FTP server.However, if the FTP server is used only for simple command operation of data files, it does not solve the problem of security and reliability of data files, and it is known from Section3 that the path of data file transmission can be controlled by using fuzzy control algorithm to achieve the effect of “encryption.” Based on this, this paper proposes a data file security policy model using a fuzzy control algorithm, and its model block diagram is as follows (Figures 7, 8).Figure 7
The working process of data file interaction by ftp under traditional passive mode.Figure 8
The model of data file security interaction based on fuzzy control algorithm constructed in this paper.For Figure7, traditional pasv mode, because the server will open a port for the client to connect, but if the opening of this port does not detect which client’s IP is connected, then the security of the data file is naturally threatened and affected when the interaction is carried out. Also, since many FTP servers open data connections randomly, if the FTP server does not determine whether the port requested by the client is a legitimate login when receiving data, other illegal users may attack it in order to get some critical data files [12]. In addition, the FTP server can also generate buffer overflow when interacting with data files on the client side, which can cause data file loss problems. In order to prevent such problems, this paper introduces a fuzzy control algorithm to set cache when the FTP server and client interact with each other to reduce data file loss.


### 4.3. Experiment on Secure Data File Interaction under Fuzzy Control

After the above analysis, in order to test whether the new strategy proposed in this paper can guarantee the security of data files and because the data cache conflict phenomenon has randomness. In order to test whether the [13]new strategy proposed in this paper can guarantee the security of data files and because the data cache conflict phenomenon has the characteristics of randomness and instability, this paper will measure the loss of data file transfer and download and the efficiency of transfer and download under windows + VMware Workstation virtual CentOS6.5 operating system for the data file transfer interaction between traditional FTP server and FTP server based on a fuzzy algorithm, and finally, the experimental results are shown in Figures 9–11.Figure 9
Loss of the number of transferred files and downloaded files for traditional FTP server data interaction.Figure 10
Loss of the number of files transferred and downloaded during FTP server data file interaction based on fuzzy control.Figure 11
Comparison of the correct rate of data file interaction under two models.Comparing Figures9 and 10, it can be seen that the average loss rate of data files under the traditional FTP server model is about 4%, while after adding the fuzzy control algorithm to intervene in the data file interaction, the average loss rate is reduced to about 2.5%, and the data file interaction under the new model is about 1.5% lower than the traditional loss rate; then observe Figure 11. The comparison of the correct rate under the data file interaction model shows that the correct rate of the traditional FTP server number file decreases to more jittery with the increase of data volume, and its accuracy rate is also lower than that of the data file interaction model under the fuzzy control algorithm based on the fuzzy control algorithm.


## 4.1. Basic Implementation of ftp Server

There are two ways to connect FTP. One is the connection of control command, i.e., the connection between client and server; one is the connection of data transfer, and the FTP service program generally supports two different working modes, which are passive (passive) mode and active (port) mode. The connections in both of these modes are shown Figures5 and 6.Figure 5
Control connection and data connection in port mode.Figure 6
Control connection and data connection in passive mode.In active mode, FTP runs on ports 20 and 21, where port 20 is mainly used for data flow transfer between the client and the server, and port 21 is mainly used for transferring commands for interaction between the client and the server. In active mode, the client firstly requests a control connection to port 21 of the server, secondly sends port commands to the server through port 21 on the connection, and finally, the FTP server transfers data files through the data connection port indicated by the port command. Since port mode has specified that port 20 and port 21 must be used, to establish the development of FTP server data file transfer, the passive mode must be used, which works as shown in Figure6.In the passive mode, the biggest difference from the active mode is that its server control port is 21, but the data port is a random port larger than 1024. Therefore, in the passive mode, the data port of the client has to actively connect to the data port of the server, whose data port is random.


## 4.2. General Framework of Data File Security Policy under Fuzzy Control

First of all, the analysis of data security problems shows that most data files have the risk of data leakage problems related to the transmission or sharing of data files, so this paper mainly focuses on the data security problem when data files are transmitted and shared under the study of data file security policy. Based on the analysis and discussion in the previous section, data files are generally transmitted using software-based and protocol-based methods. Since there is no specific research significance for software-based data file transmission, this paper focuses on a new model for the secure transmission of protocol-based data files.The first 3 sections analyze the advantages and disadvantages of HTTP and FTP and get the conclusion that both of them use plaintext transmission and have problems such as poor security and confidentiality. Since HTTP protocol is mostly a data file transfer on a browser, and an FTP server is essentially a “copy” of data files between two computers, this paper studies the construction of a security policy for data file transfer using an FTP server.However, if the FTP server is used only for simple command operation of data files, it does not solve the problem of security and reliability of data files, and it is known from Section3 that the path of data file transmission can be controlled by using fuzzy control algorithm to achieve the effect of “encryption.” Based on this, this paper proposes a data file security policy model using a fuzzy control algorithm, and its model block diagram is as follows (Figures 7, 8).Figure 7
The working process of data file interaction by ftp under traditional passive mode.Figure 8
The model of data file security interaction based on fuzzy control algorithm constructed in this paper.For Figure7, traditional pasv mode, because the server will open a port for the client to connect, but if the opening of this port does not detect which client’s IP is connected, then the security of the data file is naturally threatened and affected when the interaction is carried out. Also, since many FTP servers open data connections randomly, if the FTP server does not determine whether the port requested by the client is a legitimate login when receiving data, other illegal users may attack it in order to get some critical data files [12]. In addition, the FTP server can also generate buffer overflow when interacting with data files on the client side, which can cause data file loss problems. In order to prevent such problems, this paper introduces a fuzzy control algorithm to set cache when the FTP server and client interact with each other to reduce data file loss.


## 4.3. Experiment on Secure Data File Interaction under Fuzzy Control

After the above analysis, in order to test whether the new strategy proposed in this paper can guarantee the security of data files and because the data cache conflict phenomenon has randomness. In order to test whether the [13]new strategy proposed in this paper can guarantee the security of data files and because the data cache conflict phenomenon has the characteristics of randomness and instability, this paper will measure the loss of data file transfer and download and the efficiency of transfer and download under windows + VMware Workstation virtual CentOS6.5 operating system for the data file transfer interaction between traditional FTP server and FTP server based on a fuzzy algorithm, and finally, the experimental results are shown in Figures 9–11.Figure 9
Loss of the number of transferred files and downloaded files for traditional FTP server data interaction.Figure 10
Loss of the number of files transferred and downloaded during FTP server data file interaction based on fuzzy control.Figure 11
Comparison of the correct rate of data file interaction under two models.Comparing Figures9 and 10, it can be seen that the average loss rate of data files under the traditional FTP server model is about 4%, while after adding the fuzzy control algorithm to intervene in the data file interaction, the average loss rate is reduced to about 2.5%, and the data file interaction under the new model is about 1.5% lower than the traditional loss rate; then observe Figure 11. The comparison of the correct rate under the data file interaction model shows that the correct rate of the traditional FTP server number file decreases to more jittery with the increase of data volume, and its accuracy rate is also lower than that of the data file interaction model under the fuzzy control algorithm based on the fuzzy control algorithm.


## 5. Conclusion

In this paper, through the analysis of the security risk of data files, it is found that the security problems of data files are essentially related to the interaction and sharing of data files, while data files have data file loss and data buffer overflow caused by data file security problems when passing HTTP or FTP. After a detailed analysis of the advantages and disadvantages of HTTP and FTP, through the reading of related literature, it is found that the fuzzy control algorithm can change the transmission path of data files and make appropriate corrections for incorrect file transmission paths through fuzzy rules, thus improving the accuracy of data files during data transmission and download interactions.



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*Source: 2010419-2022-08-29.xml*