MODIFICATION OF ULC BLOCK CIPHER BASED ON RESISTANCE TO DIFFERENTIAL CRYPTANALYSIS ATTACKS

• Main Author: Chandra, Faris
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/84843
• Institution: Institut Teknologi Bandung

The rapid development of the Internet of Things (IoT) has significantly transformed how we interact with technology. This growth is driven by advances in wireless technology, increased computing capacity, and the need for smart solutions across various industrial sectors. However, this development also increases the security risks of IoT devices, which can lead to significant financial and operational losses. For example, the 2016 DDoS attack using the Mirai malware caused major disruptions to internet services worldwide, highlighting the vulnerabilities of IoT devices and the importance of enhancing security. One effective solution is cryptography, which protects data through encryption. However, IoT devices with limited computational power require lightweight cryptographic algorithms. Research shows that one such lightweight algorithm, Ultra Lightweight Cryptosystem (ULC), is vulnerable to differential cryptanalysis attacks using Mixed-Integer Linear Programming (MILP) techniques. This research aims to design modifications to ULC to enhance its resistance to differential cryptanalysis attacks. Using the Design Science Research Methodology (DSRM), the study analyzes the components of ULC to identify the causes of its vulnerability, then designs and evaluates these modifications. The results show that ULC's vulnerability is due to its involutive permutation component, which does not provide adequate security. Security evaluations of ULC, ULC-PUFFIN, and ULC- ICEBERG, all using involutive permutation, indicate an attack probability higher than the security threshold of 2!"#. In contrast, the ULC-GIFT modification demonstrates a significant security improvement with an attack probability much lower, at 2!$#$. Performance evaluations show that all ULC modifications have nearly the same speed, approximately 22,9 milliseconds, without significant performance degradation and similar RAM and ROM consumption. Thus, the ULC- GIFT modification proves to enhance security without significantly affecting performance.