The Effect of Block Cipher Modes on Confidentiality and Authentication in Network Communication Security

Abstract

With communication expanding rapidly over the internet, the importance of information encryption increases to protect privacy, preserve data integrity, and combat network security threats. While various types of encryption algorithms exist, block encryption algorithms are most commonly used to provide the optimum level of security versus performance. However, the operating mode of these algorithms plays a major role in the time spent performing encryption and decryption, as well as the ability to resist certain types of attacks. The majority of prior research has concentrated on traditional block encryption operating modes, including ECB, CBC, CTR, and OFB. There has been little research conducted on comparative studies of the newer block encryption operating modes: GCM, CCM, and EAX. This type of comparison between these newer modes and their more traditional counterparts will help to inform the decision when selecting the most efficient and secure block encryption algorithm. The proposed work is performed in two phases. The first phase consisted of performance testing of the aforementioned block encryption operating modes (GCM, CCM, and EAX). The results of this first phase showed that GCM and CCM offer superior encryption and decryption speeds compared to EAX, which is much slower by comparison. The second phase required testing of the EAX mode of operation using three different types of block encryption algorithms: AES, Blowfish, and CAST. During this phase, AES demonstrated the highest performance, followed by Blowfish, and the lowest performance was obtained with CAST. Keywords- Symmetric cryptography; Block cipher algorithms; Modes of operation; GCM mode; CCM mode; EAX mode.