International Journal For Multidisciplinary Research

E-ISSN: 2582-2160     Impact Factor: 9.24

A Widely Indexed Open Access Peer Reviewed Multidisciplinary Bi-monthly Scholarly International Journal

Call for Paper Volume 7, Issue 3 (May-June 2025) Submit your research before last 3 days of June to publish your research paper in the issue of May-June.

Simulating Brute Force Attacks on Vigenère and AES Ciphers in Python: Measuring Key Size Impact on Security

Author(s) Mr. Virgilio Flores Tuga, Mr. Lloyd Vincent Pedraroja Cubero
Country Philippines
Abstract The security of modern digital communications depends heavily on the robustness of cryptographic algorithms against brute force attacks. This study investigates the impact of key size on the brute force resistance of two representative symmetric ciphers: the classical Vigenère cipher and the Advanced Encryption Standard (AES). Using Python, the research implements a systematic simulation that incrementally increases key sizes and measures the corresponding computational effort required to recover plaintext through exhaustive key search. The simulation spans key lengths of 2–5 characters for Vigenère and 12–20 bits for AES (with reduced keyspace for feasibility), recording both the average time and the number of attempts needed to break each cipher. Results show an exponential growth in attack effort with increasing key size for both algorithms: even modest increments in key length yield orders-of-magnitude improvements in brute force resistance. These findings provide concrete, empirical evidence supporting cryptographic best practices that mandate adequate key lengths for secure communications. The study underscores the continued relevance of key size as a fundamental defense mechanism in both legacy and modern symmetric encryption systems, offering valuable insights for security practitioners and educators alike.
Keywords Advanced Encryption Standard, brute force attack, key size, Vigenère cipher
Field Computer > Network / Security
Published In Volume 7, Issue 3, May-June 2025
Published On 2025-06-19
DOI https://doi.org/10.36948/ijfmr.2025.v07i03.48532
Short DOI https://doi.org/g9qxbc

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