Fahlome, Dodyk, and Dea Alya. “Incoming Mail Security Using AES-128 Encryption With QR Code Verification at the North Sumatra Provincial Inspectorate”. Jurnal Metrokom : Media Teknik Elektro dan Komputer 2, no. 2 (December 31, 2025): 116–135. Accessed August 14, 2026. https://ejournal.ypayb.or.id/index.php/metrokom/article/view/129.