Study on an Enhanced Stream Cipher Algorithm Based on Random Hashing

In response to the issues of traditional stream cipher mechanisms based on exclusive-OR (XOR) operation, which has a single encryption and decryption method and whose security entirely relies on the key stream, this paper proposes a stream cipher algorithm based on random hashing. Firstly, we utilize Nonlinear Feedback Shift Registers (NLFSRs) to generate high-security pseudorandom sequences, enhancing resistance against correlation and algebraic attacks. Secondly, a specific XOR operation for designated plaintext positions, combined with a random hashing algorithm inspired by N -way merging, is designed to replace the traditional XOR operation in stream ciphers, effectively preventing Many-Time-Pad (MTP) attacks. Finally, this algorithm maintains the same time and space complexity as traditional XOR operation-based stream cipher algorithms. Still, experimental results show that when the pseudorandom sequence is short, this algorithm exhibits higher code uniformity and is particularly effective for encrypting short information.