A modified RC‐4 cryptosystems to enhance security by using negative key schedule

Abstract

As technology rapidly advances and internet reliance grows for daily activities, the demand for robust and efficient cryptographic protocols is undeniable. Cryptography, the art of secret writing, uses symmetric mathematical functions to secure data in transit or at rest. Stream ciphers, unlike block ciphers, encrypt data sequentially, eliminating the need for padding with extra bits to complete a block. Rivest Cipher 4 (RC‐4) has been one of the most widely used stream ciphers. However, vulnerabilities exploited by attackers in 2014 led to its widespread replacement. In this paper, we introduce a modified version of RC‐4 designed to address and mitigate the security threats of traditional RC‐4. By incorporating negative numbers into the key generation schedule, our preliminary analysis shows promising results. This adaptation not only enhances RC‐4's security features but also revitalizes its applicability in modern cryptographic scenarios, potentially restoring its viability as a secure cryptographic tool.