A new block cipher algorithm that adopts the magic square of the fifth order with messages of different lengths and multi-function in GF(2^8)

Abstract

This paper is considered as a development of encryption algorithms based on Magic Square of Order Five. Both GF(P) and  GF(2⁸) are used to encode both images and text. Where two different algorithms were used, the first using message length = 10 and the second message length = 14, and an unspecified number of rounds were added and a mask will be used in the even round will use the addition operation and in the odd round will used the multiplication operation so that the text resulting from the first round will be as input text for the next Round, and thus. The speed, complexity, NIST tests and histogram for the first ten rounds were calculated and compared with the results of the previous algorithm before the rounds were made, where the complexity in the first algorithm was = ((256) ¹⁵)^r+1× (256)¹⁰ + or × (256)²⁵ and the complexity in the second algorithm = ((256)¹¹)^r+1 ×(256)¹⁴ + or × (256)²⁵ where r represents the number of round used.