Secure File Encryption with EE-AES

Abstract

Secure communication applications rely heavily on strong encryption algorithms to ensure confidentiality and integrity. Traditional AES provides robust security, but known structural patterns in the S-Box and predictable transformations in MixColumns make it a target for advanced cryptanalysis. This paper proposes an Enhanced Encryption AES (EE-AES) algorithm that replaces the MixColumns operation with a Bitwise Reverse Transposition (BRT) technique and introduces a Dynamic S-Box generated per session. These modifications increase diffusion, reduce predictability, and minimize vulnerability to algebraic attacks. The proposed system is implemented as a secure multi-platform communication application supporting encrypted text messaging. Preliminary results from the completed encryption module indicate improved randomness and stronger resistance to differential and linear analysis. Decryption implementation is in progress.

Introduction

The text presents EE-AES, an enhanced version of the Advanced Encryption Standard (AES), designed to strengthen data confidentiality and integrity for secure multi-platform communication. Standard AES is efficient but uses static structures like fixed S-Boxes and MixColumns, which can create predictable patterns exploitable by attackers. EE-AES addresses these vulnerabilities by introducing dynamic S-Box generation and Bitwise Reverse Transposition (BRT) to improve confusion, diffusion, and resistance to cryptanalysis.

Key Features and Methodology:

1. Dynamic S-Box Generation – The S-Box is created per session using a cryptographically strong seed and key-dependent permutations, ensuring that identical plaintexts produce different ciphertexts.

2. Bitwise Reverse Transposition (BRT) – Replaces MixColumns with bit-level reversal and transposition of bytes across the state matrix, improving diffusion while remaining computationally efficient.

3. EE-AES Encryption Flow – Follows AES rounds with added dynamic S-Box substitution and BRT steps, producing ciphertext that is highly unpredictable.

4. EE-AES Decryption – Uses inverse operations (inverse dynamic S-Box and reverse BRT) to recover plaintext accurately, ensuring data integrity.

System Workflow:

• User inputs plaintext → EE-AES encryption → secure transmission → receiver decrypts → plaintext displayed.

• Encryption ensures confidentiality; decryption guarantees correct reconstruction only for authorized users.

Results and Analysis:

• Functional Validation: Successfully encrypts/decrypts files without data loss.

• Security Enhancement: Stronger confusion and diffusion, high avalanche effect, resistance to linear/differential cryptanalysis and known-plaintext attacks, and improved key dependency.

• Performance: Slight increase in processing time due to additional operations, but remains acceptable; memory usage is efficient.

• User Interface: Simplified for file encryption/decryption with secure local processing.

Conclusion

This paper presents an enhanced AES model, EE-AES, that incorporates Dynamic S-Box generation and Bitwise Reverse Transposition to overcome structural limitations of standard AES[1][5][6].The proposed approach increases security by reducing predictability and strengthening resistance to cryptanalytic attacks. A secure communication application using EE-AES has been developed, with encryption completed and decryption in progress. Future work includes full decryption validation, performance benchmarking, and expanding support for multimedia communication.

References

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Copyright

Copyright © 2026 Akash A S, Anandhu A S, Karthik U, Vinayak Vimal, Ms. Mithra Viswanadhan. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.