Security Enhancement of AES-CBC and its Performance Evaluation Using the Avalanche Effect

The security of communication systems is becoming a significant concern with the increase in computational power. High-security cryptographic algorithms are required to protect the privacy of information from unauthorized access. This paper presents a security enhancement of Advanced Encryption Standard (AES) in Cipher Block Chaining (CBC) mode and its performance evaluation using the Avalanche Effect. In this study, a new improved technique for increasing the security of the AES-CBC is introduced. The Unix time is used as a source for Initialization Vector (IV) in CBC mode before encryption rounds. The results showed that the algorithm generates different ciphertext at each execution. In other words, different ciphertext output significantly decreases the risk of cracking the encryption key. Moreover, the results are examined using the Avalanche Effect and tested for satisfying the security criteria. The achieved results showed that the encryption method succeeds in maintaining the avalanche effect requirement and introducing additional strength to the encryption process by preventing the encryption key update for every new ciphertext.