Evaluation of Security and Performance Impact of Cryptographic and Hashing Algorithms in Site-to-Site Virtual Private Networks

The secure and efficient operation of Site-to-Site Virtual Private Networks (VPNs) is critical for modern data transmission, yet the current literature lacks a comprehensive analysis of the trade-offs between security and performance. This paper addresses this gap by evaluating the impact of various cryptographic algorithms and hashing functions on VPN performance. Evaluating the impact of cryptographic algorithms on network performance in a Site-to-Site VPN is essential for determining data transmission efficiency. Several factors, including encryption methods, hashing, bandwidth limitations and others could, influence VPN performance. Further, cyberattacks such as Denial of Service (DoS), Media Access Control (MAC) flooding, and synchronize (SYN) flooding can target VPN infrastructures. Therefore, it is crucial to assess cryptographic algorithms to identify the most suitable ones for different network characteristics and find balance that the end user needs. The paper's contributions are threefold. Firstly, it explores the complex relationship between cryptographic and hashing algorithms and their implications for security and network performance, aiming to enhance Site-to-Site VPN security without compromising efficiency. Secondly, we implement a dynamic VPN configuration tool and conduct performance tests in a virtual environment using Graphical Network Simulator-3 (GNS3) and File Transfer Protocol (FTP), Datafile transfers to measure the impact of various encryption pairs, including Advance Encryption Algorithm (AES), Data Encryption Standard (DES), Triple Data Encryption Standard (3DES), and hashing functions such as Secure Hash Algorithm 2 (SHA2) and Message Digest (MD5). Finally, we assess the resilience of VPNs to specific cyberattacks and evaluate the trade-offs between security and transmission efficiency. The findings show that 3DES with SHA2 offers an acceptable balance between speed and security, making it a solid choice when both are important.