KNUDSEN, L. R. Iterative Characteristics of DES and S^2-DES. DAIMI Report Series, [S. l.], v. 22, n. 439, 1993. DOI: 10.7146/dpb.v22i439.6756. Disponível em: https://tidsskrift.dk/daimipb/article/view/6756. Acesso em: 9 may. 2024.