Firliansyah A, Fauzi A, Sembiring H. Watermarking QR Code Application On Birth Certificates Using The Discrete Cosine Transform (DCT) Method. INDOTECH [Internet]. 2023 Aug. 31 [cited 2026 Aug. 21];1(2):56-65. Available from: https://jurnal.intekom.id/index.php/indotech/article/view/46