Instal : Jurnal Komputer E-ISSN: 2808-683X Edisi : Volume 17 Nomor 08 | 2025 Available online at https://journalinstal.
org/index.
php/Instal/index Implementation of RC4 Stream Cipher for Data Security in Internet
Cafy Billing Systems Nasib Marbun
Universitas Negeri Manado
ARTICLE INFO
ABSTRACT
Article history:
In the field of data communication, cryptography plays a crucial role in ensuring data confidentiality, authenticity, and integrity.
This technique is essential when transmitting sensitive information over public networks, preventing unauthorized access or manipulation.
In the context of internet cafys .
, which provide global computer network access, a secure billing system is vital to prevent data tampering related to user activity duration and associated charges.
This study applies the RC4 stream cipher encryption algorithm to protect the billing data.
By encrypting user data before storage, the system ensures its confidentiality and integrity.
The implementation, developed using Visual Basic 6.
0, demonstrates that the encrypted data .
maintains a consistent structure with the plaintext, indicating effective encryption without increasing data size.
This solution enhances security in internet cafy billing systems.
Received : 05 May 2025 Revised : 06 June 2025 Accepted : 30 September 2025 Keywords:
Cryptography.
Data Security.
RC4.
Stream Cipher.
Internet Cafy.
Billing System.
This work is licensed under a Creative Commons Attribution 0 International License.
Corresponding Author:
Nasib Marbun Universitas Negeri Manado Email: nasibmarb@gmail.
INTRODUCTION
In the digital era, information technology has become a fundamental component in almost every aspect of life, particularly in data communication and information processing.
With the increasing reliance on interconnected systems such as the internet, securing digital information from unauthorized access has become a critical concern.
The integrity, confidentiality, and authenticity of transmitted or stored data must be ensured to maintain trust and operational continuity.
This has led to the growing importance of data security as a core requirement in both personal and enterprise-level applications.
One specific environment that demonstrates the urgency of data security is the internet cafy .
Internet cafys provide users with public access to the internet, allowing them to engage in browsing, communication, online transactions, and more.
These interactions are typically logged and processed through a billing system, which records session duration, cost calculations, and usage logs.
The information generated in this system is sensitive, as it involves both user behavior and financial data.
Without proper protection, this data is susceptible to manipulation, unauthorized modification, or malicious exploitation, which could harm both users and business owners.
To address this vulnerability, cryptographic Page : 552-558 Nasib Marbun Doi : https://doi.
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methods can be integrated into the billing system to ensure the security of stored and transmitted data.
Cryptography is a branch of science that focuses on techniques for secure communication by transforming data into a form that cannot be easily understood by unauthorized parties.
Among the various cryptographic algorithms available, the RC4 stream cipher stands out for its simplicity, speed, and ease of implementation.
Despite being an older algorithm.
RC4 has been widely used in protocols like SSL (Secure Sockets Laye.
and WEP (Wired Equivalent Privac.
, particularly in lightweight applications where computational resources are limited.
This research proposes the application of the RC4 stream cipher to secure the data stored in an internet cafy billing system developed using Visual Basic 6.
The main objective is to encrypt session data, making it unreadable to anyone who does not possess the correct decryption key.
Through this approach, the billing recordsAisuch as user activity duration and chargesAiare protected against tampering, thereby ensuring accurate, secure, and reliable data management within the cafy The rest of this paper is organized as follows: Section 2 discusses the methodology and technical implementation of data security, billing systems, and the RC4 Section 3 presents the results and implementation details, followed by an analysis of system performance.
Section 4 concludes with key findings and recommendations for further research and development.
METHODS
Data Security Data is a file that can be confidential so it requires a data security process to maintain its Cryptography is the process of securing data that can be used based on the use of algorithms, one of which is.
RC4 Stream Cipher.
Cryptography is one of the appropriate data security solutions or methods to maintain the confidentiality and authenticity of data, and can improve the security aspects of data or information.
Cryptography is a field of science that studies data encoding techniques.
Text data is data that has characteristics such as letters, numbers, symbols contained in a document or is a form that does not have objects such as images.
Securing text data in the form of ciphertext and the resulting ciphertext results do not increase the capacity of the original data to be one of the commonly known problems that the dominant ciphertext results increase capacity, for that the author tries to secure it with Block Cipher and Stream Cipher.
Data security can be done in two ways.
The first way is setting the permissions of each user by the database The second way is data security in terms of data content stored in the database.
Internet Cafe Billing System In this billing, all data is stored in a mysql database, so it can be easier for the owner to see the number of consumers and the length of time consumers make rentals.
Billing Hotspot is an application used for managing internet access users, such as recording transactions and monitoring users.
The input of this research is data that is sent in real time from the billing machine, from a series of trials that have been carried out it can run smoothly, which is evidenced by measuring data transmission with speed in accessing article data an average 7833 seconds / transaction data manually.
RC4 Stream Cipher The RC4 algorithm (Ron's Code/Rivest's Ciphe.
is an algorithm that can be used to encrypt data so that the original data can only be read by someone who has the encryption .
The RC4 stream cipher algorithm is used to convert the actual data into certain symbols, so that the data will not be understood by parties who do not have access .
The hardware specifications used for the implementation of making and running Page : 552-558 Nasib Marbun Doi : https://doi.
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the program so that it runs properly are as follows:
Processor : Minimum Pentium i-800 Mhz Memory : Minimum 64 MB Hard disk : Minimum 5 GB Graphics Card : VGA 8 MB with SVGA monitor Monitor : SVGA 1924x78 pixels into 16 Bit color.
In making this program required some software, namely:
Operating system : Windows 98 SE.
Windows ME, or Windows XP Application : Visual Basic 6.
RESULTS AND DISCUSSION
Training Data With VB 6.
RC4 has an S-Box.
S0.
S1,AA.
S255, which contains permutations from 0 to 255.
It uses two indexes, namely i and j in its algorithm.
Index I is used to ensure that an element changes, while index j will ensure that an element changes randomly.
In essence, in the encryption algorithm this method will generate pseudorandom bytes from the key which will be subjected to XOR operations on the plaintext to produce ciphertext.
And to produce the original plaintext, the ciphertext will be subjected to an XOR operation against the pseudorandom bytes.
In the following, a chart will be provided illustrating the series of processes that are executed to encrypt or decrypt data.
The following will explain the parts of the RC4 Stream Cipher algorithm along with its implementation as follows:
: encryption Ascii plaintext : 101 110 107 114 105 112 115 105
Key
: computer Ascii key
107 111 109 112 117 116 101 114
Implementation To run this image processing software, it is enough to run the Billing.
exe file, after runningit will display a flash display as follows:
Figure 1.
Flash Display Page : 552-558 Nasib Marbun Doi : https://doi.
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This form is used as the main menu of the system, as shown in the image below:
Figure 2.
Main Menu Form This menu is a sub menu of the file menu, as shown in the image below:
Figure 3.
File Menu This menu is a sub menu of the view menu, as shown in the image below:
Figure 4.
View Menu This form is used to perform the process of switching usage between computers, as shownin the image below:
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This form is used to view encrypted information, as shown in the image below:
Figure 5.
Transfer Account Form Figure 6.
Encryption Results This form is used to view decrypted information, as shown in the image below:
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Figure 7.
Decryption Results This form is used to view connected client information, as shown in the image below:
Figure 8.
Users Are Connected CONCLUSION Based on the implementation and evaluation of the internet cafy billing system secured using the RC4 stream cipher, it can be concluded that the integration of cryptographic techniques significantly enhances the confidentiality and integrity of user data.
The RC4 algorithm, despite its simplicity, has proven effective in encrypting session records such as user duration and usage charges, preventing unauthorized access or manipulation of billing The encryption process ensures that each userAos activity data is transformed into ciphertext before storage, and can only be decrypted with the corresponding key.
This method not only protects sensitive data but also ensures that any attempt to tamper with the data results in unreadable content.
The system developed using Visual Basic 6.
demonstrates consistent and accurate encryption-decryption functionality, with ciphertext output having equal length and structure to the original plaintext, thus maintaining data size However, while RC4 was suitable for the purpose of this study due to its ease of implementation and computational efficiency, it is important to acknowledge that RC4 has known vulnerabilities in modern cryptographic standards.
Therefore, for future Nasib Marbun Page : 552-558 Doi : https://doi.
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enhancements, it is recommended to consider adopting more secure algorithms such as AES or ChaCha20, especially for applications requiring stronger resistance against cryptanalytic In conclusion, the research validates that the application of the RC4 stream cipher in a billing system context is a viable approach to securing data in internet cafys.
This method provides an essential foundation for building trust in public computing environments by ensuring that user information is kept secure, confidential, and tamper-resistant.
REFERENCES