My ptychio thesis deals with the construction and evaluation of structures which can be used for software watermarking. More specifically, I have constructed and evaluated the algorithm which had been published in the paper: Maria Chroni and Stavros D. Nikolopoulos, Efficient Encoding of Watermark Numbers as Reducible Permutation Graphs, CoRR, abs/1110.1194, 2011. The construction has done in programming language C, with the ability to recognize attacks, at various levels, as well as the repair many of these. The text of the work is here in greek language.