A Multi Rounds Block Cipher Algorithm Using Magic Square of Order Nine with Block Size Equal to 18 and 23

This paper aims to develop encryption technique that is based on the properties of the magic square of order nine. Where magic sum is the works main focus, keys values are placed in specified locations, and message was placed in the remaining locations, where the magic sum is calculated an unspecified number of rounds is added to the proposed algorithm to achive higher to double complexity for each round. the work was carried out using GF(P) and GF(2⁸). Two techniques were proposed, the first using 18 sums opposite to the length of message, and the second using 23 sums opposite to the length of message. The complexity in the first algorithm using GF(P) is (256)¹⁸ x (P)⁶³, while using GF(2⁸) is (256)¹⁸ x (256)⁶³, and when adding one round, reaches double, which is equal to ((256)¹⁸ x ((P)) 63)² and ((256)¹⁸x((256)⁶³)² arriving to ((256)¹⁸x(((P)⁶³)¹¹ and ((256)¹⁸x((256)63)¹¹) when adding ten Rounds, As for time, it keeps it less than half when adding each round. While the complexity in the second algorithm using GF(P) is (256)²³×(P)⁵⁸, while using GF(2⁸) is (256)¹⁸ × (256)⁶³, and when adding one round, it reaches double, which is equal to ((256)²³×((P)⁵⁸)2 and ((256)²³ x ((256)⁵⁸)² arriving at ((256)²³ x(((P)⁵⁸)¹¹ and ((256)²³x((256)⁵⁸)¹¹) when adding ten Rounds, As for time, it keeps it less than half when adding each round.