Watermarking Competency Certificates with Value Images Using the Descrete Cosine Transform (DCT) Method. Pascal: Journal of Computer Science and Informatics, [S. l.], v. 2, n. 01, p. 33–37, 2024. Disponível em: https://jurnal.devitara.or.id/index.php/komputer/article/view/117.. Acesso em: 13 dec. 2025.