Implementation of the Vigenere Cipher Algorithm in a Python GUI-Based Text Encryption App

Abstract

Rapid advances in information technology have increased the risk of data theft and misuse in digital communications. Cryptography is a scientific solution for ensuring the confidentiality, integrity, and authenticity of data. The Vigenère Cipher is one of the best-known classical cryptographic algorithms, developed by Blaise de Vigenère in the 16th century, which uses a polyalphabetic substitution method based on a repeating key and falls under the category of symmetric cryptography. This research implements the Vigenère Cipher algorithm in a desktop application named VigCrypt, built using the Python 3 programming language and the Tkinter framework as the graphical user interface (GUI). Unlike previous research, which mostly implemented the Vigenère Cipher on web- or mobile-based platforms, this study focuses on a desktop application that serves not only as an encryption tool, but also as a medium for learning cryptography. The developed application features text encryption and decryption, visualization of the calculation steps for each character—displaying numerical values and modular calculations explicitly—a 26x26 Vigenère Square table as a visual reference, and the ability to export results to a .txt file. Functional testing was conducted on 10 plaintext samples covering various text types, including short text, sentence-length text, and alphanumeric text. The test results showed a 100% accuracy rate for both encryption and decryption, with all non-alphabetic characters such as spaces, numbers, and punctuation marks—successfully preserved.