Fully Dynamic Advanced Encryption Standard

As the reliance on using electronic services increases, the use of a strong encryption algorithm becomes paramount. The AES is the most widely used cipher. However, AES uses static transformations that attackers might exploit to cryptanalyze AES. In this research paper, we propose the Fully Dynamic Advanced Encryption Standard (FDAES). The FDAES inherits the strength of the AES cipher, including its resistance to all known attacks, such as linear and differential cryptanalysis. However, all internal transformations used to perform encryption and decryption will operate differently depending on the encryption key value. Each of these transformations is defined on a finite field F<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2⁸</sub> with a precise algebraic formulation. FDAES achieves 128 transformation variants per round, resulting in 2<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">98</sup> cipher variants in 14 rounds. No one knows which version is currently used, except for the holders of the encryption key. In benchmark tests, FDAES achieved an encryption time of 0.27 seconds and a decryption time of 0.129 seconds for 1,000 bytes, compared to 0.13 seconds and 0.127 seconds for AES. Statistical testing confirms that FDAES satisfies the avalanche criterion with bit-flip ratios of 49. 8% and 51. 1% for key and plaintext sensitivity, respectively. Moreover, it passed all 15 tests in the NIST Statistical Test Suite, and a minimum of 25 active S-Boxes in 4-round trails ensures strong resistance against differential and linear cryptanalysis.