Design and Implementation of a Simplified Secure File Transfer Protocol (S-SFTP)

The complexity of standard Secure File Transfer Protocol (SFTP) implementations tends to be a barrier for educational environments, as they focus on real-world applications, rather than facilitating the understanding of fundamental network security concepts. This work presents a novel implementation and analysis of a Simplified Secure File Transfer Protocol (S-SFTP), designed specifically as an accessible educational platform for teaching secure data transfer mechanisms through a hands-on implementation. The protocol employs a deliberately streamlined client-server architecture implemented in C++ using basic socket programming, with AES-256-CBC encryption for data security and SHA-256 hashing for integrity verification. This system utilizes a pre-shared key approach and features a modular design with separate components for cryptographic operations and logging, for better code readability. Through extensive performance testing with files with sizes ranging from 1 KB to 100 MB demonstrates that transfer times increase linearly with file size. Network security analysis using packet capture tools confirms successful data encryption during transmission, with the 256 -bit keyspace making traditional bruteforce attacks computationally infeasible. The protocol achieves its primary objective by providing an open-source platform that bridges theoretical network security concepts with practical implementation, enabling learners to directly observe, modify, and understand the effects of implementation choices on secure file transfer mechanisms.