Enhancing block cipher security with key-dependent random XOR tables generated via hadamard matrices and Sudoku game.

This article focuses on proposing efficient methods to generate t-bit random XOR tables and applying them to create dynamic, key-dependent block cipher algorithms, specifically enhancing the Advanced Encryption Standard (AES). Two main XOR table generation techniques are introduced: one based on Hadamard matrices and another inspired by the Sudoku game, with the latter capable of producing a broader variety of XOR tables. The authors implement these methods in AES-128, resulting in dynamic AES variants (DAES-128 and SDAES-128) that replace the fixed XOR operation with key-dependent random XOR tables. Security analyses indicate that these dynamic AES algorithms significantly increase resistance to linear and differential cryptanalysis by complicating attack strategies, while randomness assessments using NIST SP 800-22, Shannon entropy, and min-entropy demonstrate that the proposed algorithms meet or exceed the statistical randomness standards of the original AES. The paper also discusses practical considerations such as increased memory and computation time for XOR table generation and acknowledges that side-channel attacks remain a concern regardless of the dynamic approach.