YOUSIF, Intisar Abid. Proposed A Permutation and Substitution Methods of Serpent Block Cipher. Ibn AL- Haitham Journal For Pure and Applied Science, [S.l.], v. 32, n. 2, p. 131-144, may 2019. ISSN 2521-3407. Available at: <http://jih.uobaghdad.edu.iq/index.php/j/article/view/2120>. Date accessed: 13 oct. 2019. doi: http://dx.doi.org/10.30526/32.2.2120.