Publication Search

The dissemination of personal data through digital media has increased significantly alongside the growing use of Quick Response (QR) Codes for various purposes, such as electronic tickets, certificates, and digital identities. Conventional QR Codes are open and can be easily scanned, copied, or manipulated by unauthorized parties. The personal data referred to in this study includes sensitive information such as full name, identity number (NIK/National ID), date of birth, address, phone number, and email address. This research proposes a layered security system that combines the Advanced Encryption Standard (AES) cryptographic algorithm with steganography using the Discrete Cosine Transform (DCT) method. The process begins with encrypting personal data using AES, converting the encrypted result into a QR Code, and embedding the QR Code into a digital image using DCT, hiding it in the image’s frequency domain. The digital images used are of fixed size and formats that preserve visual quality. System evaluation is carried out by testing the visual quality of the stego image, the success rate of QR Code extraction, and the integrity of the encrypted data. The results are expected to conceal sensitive information visually while maintaining its confidentiality, with potential applications in electronic ID cards, digital certificates, e-tickets, and other confidential documents.

Data security is a critical aspect in the digital era due to the increasing exchange of sensitive information through electronic media. One widely used approach to protect data confidentiality is cryptography, particularly asymmetric encryption algorithms. This study aims to analyze the implementation of the Rivest–Shamir–Adleman (RSA) algorithm as a data security mechanism through an encryption and decryption process. The research method used is an experimental approach by implementing the RSA algorithm in a text-based data security simulation. The stages include key generation, encryption, and decryption processes, followed by analysis of the correctness and effectiveness of the algorithm in maintaining data confidentiality. The results show that the RSA algorithm is capable of converting plaintext into unreadable ciphertext and successfully restoring it to its original form through the decryption process using the correct private key. This confirms that RSA provides a high level of security based on the difficulty of factoring large prime numbers. The implication of this study is that the RSA algorithm can be effectively applied to secure sensitive data transmission in information systems, especially in environments requiring strong authentication and confidentiality.

Information security is an essential aspect of digital communication, particularly in the exchange of text-based messages through open networks. Messages transmitted without protection are vulnerable to interception and unauthorized modification. One classical cryptographic technique that remains relevant as a foundational learning tool is the Caesar Cipher algorithm. This study aims to implement the Caesar Cipher algorithm for message encryption and decryption and to analyze its effectiveness and security level. The research method employed is a descriptive approach through literature review and a case study by applying character-shift techniques to text messages. The results indicate that the Caesar Cipher algorithm successfully transforms plaintext into ciphertext and restores it back to its original form through the decryption process. Although the algorithm is simple and easy to implement, it has significant limitations in terms of security due to its small key space and vulnerability to brute-force attacks. Therefore, Caesar Cipher is not suitable for protecting sensitive data but remains valuable as an introductory model for understanding basic cryptographic concepts.

Relational databases store information in interconnected tables and are widely used for data management and retrieval. However, in certain environments, the original values stored in a relational database cannot be exposed during data retrieval. This limitation creates a challenge because common encryption methods only transform data for storage and do not support mathematical operations needed for value matching. Partially Homomorphic Encryption is a cryptographic approach that allows specific mathematical operations to be performed directly on transformed data without restoring it to its original form. This study proposes the use of Partially Homomorphic Encryption to enable value-based data retrieval while keeping all stored values in their transformed form throughout the entire process. The method relies on homomorphic properties that allow mathematical comparison to be conducted on encrypted data, making the retrieval process possible without revealing the original values. The results show that this approach can perform data retrieval operations in a relational database while preserving the transformed structure of the stored data. The proposed method offers an alternative for environments that require data retrieval without exposing original values and demonstrates the potential of homomorphic techniques in supporting secure and functional data processing in relational database contexts.

MP3 audio files are often used in a variety of fields, but they are prone to security risks such as eavesdropping and illegal access. This study proposes a super encryption method by combining the algorithms of Rivest Shamir Adleman (RSA) and ElGamal to improve the protection of audio data. RSA was chosen for its efficiency and ease of implementation, while ElGamal offers a high level of security through discrete logarithmic complexity. The combination of the two is expected to address the weaknesses of each algorithm and strengthen file security. The system is developed using the Python programming language with the Visual Studio Code environment. The encryption process is done in layers: MP3 files are first encrypted with RSA, and then the results are encrypted again with ElGamal. The decryption is done in reverse order. Tests are conducted with various MP3 file sizes to measure the effectiveness and performance of the system. The results show that this method is able to secure audio files so that they cannot be accessed without the private keys of both algorithms. Although processing times are increased compared to single encryption, the level of security obtained is much higher. This approach can be an effective solution for protecting digital audio data, particularly MP3 format, and could potentially be applied to a wide range of other data types that require a high level of security.

Along with the development of the times, the use of information technology using computers as its media has increased rapidly. Indonesia is currently starting to adopt the concept of society 5.0 or what is known as Society 5.0, where this kind of activity focuses on community settings that are oriented towards IT-based human activities (Wijayanti et al., 2022). The application of the concept of "society 5.0" has brought many technological advances in various fields of life that are connected to the internet, especially in Indonesia. The base64 technique produces values ​​during text encoding that are difficult for laypeople to understand. This encryption program has the ability to convert plain text to cipher text and reverse cipher text after it is received. Several recommendations for the development of better applications in further research can be made based on the test findings of this study and the conclusions mentioned above. These include the following: The Vigenere Chipper application can only encrypt text messages    

Cryptography is a solution or method of information security that is good for maintaining the confidentiality and security of information, and can improve information or information security in an era of very rapid development of information technology. The rapid development of this technology, many new implications and problems arise in the delivery and communication of information, this is because everyone has easy access to the media and this affects the security of information and messages on the media. Therefore, to protect messages, we can use Caesar encryption, which is relatively easy to implement in PHP. How to apply message security in this study by designing web-based applications using the PHP and HTML programming languages. Message protection uses the Caesar encryption algorithm by changing every character of the original message into ciphertext. Characters in plain text are replaced with keys that are determined based on the number of alphabetical orders of plain text. In this way, unauthorized parties cannot read these private messages and users can interact with private messages more freely.

Dokumen Teks adalah dokumen yang menyajikan informasi secara tertulis. Ada berbagai jenis dokumen teks, antara lain Plain Text ( .txt ), Microsoft Word Documents ( .docx ), Portable Document Format ( .pdf ) dan lain sebagainya. Dokumen teks ini sangat penting karena berisi data dan informasi dari pihak-pihak yang berkepentingan. Untuk meningkatkan keamanan dari kebocoran data atau informasi, diperlukan suatu teknik yang disebut Kriptografi. Kriptografi adalah ilmu yang mempelajari tentang keamanan pesan, sehingga membuat pesan tidak dapat dibaca oleh orang yang tidak berwenang. Oleh karena itu penulis menggunakan metode Kriptografi yang bernama Playfair Cipher untuk diimplementasikan pada sebuah aplikasi agar aplikasi tersebut mampu mengubah file teks menjadi file terenkripsi dan sebaliknya. Untuk menganalisa proses pada aplikasi, penulis menggunakan beberapa file diantaranya ( .txt ), ( .docx ), dan ( .pdf ). Sehingga dari hasil analisis tersebut dihasilkan suatu kesimpulan bahwa semakin besar ukuran file yang akan melalui proses enkripsi atau dekripsi maka akan semakin lama pula proses enkripsi atau dekripsinya. Aplikasi yang dihasilkan akan membantu mengubah file teks menjadi file terenkripsi dan sebaliknya.

Perkembangan mengenai teknologi sudah semakin maju, setiap orang bisa dapat dengan mudah mengakses jaringan internet kapanpun dan dimanapun berada. Dalam hal ini akses internet dalam perkantoran hal yang wajib untuk menunjang operasional dan perkembangan perusahaan. Semakin besar suatu perusahaan maka akan sangat membutuhkan keamanan dan manajemen yang baik dalam melakukan pertukaran data melalui internet serta monitoring cabang dari perusahaan tersebut, serangan dan pengintaian data menjadi hal yang menakutkan karena dapat mengancam keberlangsungan perusahaan dari hal yang tidak diinginkan. Untuk mengatasi masalah tersebut perusaahan dapat menerapkan keamanan jaringan dengan menggunakan teknologi VPN (Virtual Private Network) dengan metode L2TP (Layer 2 Tunneling Protocol) dan IPSec serta menggunakan routing OSPF. Teknologi VPN ini mampu mengirimkan data melalui jaringan internet dengan mengenkripsi data terlebih dahulu sebelum dikirimkan sehingga aman dari ancaman pihak luar