Meningkatnya permintaan terhadap produk celana jeans Gotrock diikuti dengan munculnya produk tiruan yang merugikan produsen dan pelanggan. Kemiripan antara produk asli dan palsu menyebabkan pelanggan kesulitan melakukan verifikasi keaslian produk, sementara proses verifikasi manual dinilai kurang efisien. Penelitian ini bertujuan merancang dan membangun aplikasi verifikasi keaslian produk berbasis QR-Code menggunakan algoritma ECDSA. Metode pengembangan yang digunakan adalah Prototype dengan tahapan analisis kebutuhan, perancangan, evaluasi, implementasi, dan pengujian. Data diperoleh melalui observasi, wawancara, dan studi pustaka. Aplikasi dikembangkan berbasis web menggunakan PHP dan MySQL. Dalam implementasinya, id-produk diproses menggunakan ECDSA untuk menghasilkan digital signature yang kemudian dikonversi ke dalam QR-Code dan ditempelkan pada produk. Pelanggan dapat memindai QR-Code menggunakan smartphone, kemudian aplikasi melakukan verifikasi digital signature untuk menentukan status keaslian produk secara real-time. Hasil pengujian menunjukkan White Box Testing valid pada fungsi generate dan verify signature, Black Box Testing membuktikan seluruh fungsi aplikasi berjalan sesuai kebutuhan, serta UAT memperoleh tingkat penerimaan sebesar 96% oleh admin dan 93,8% oleh pelanggan. Aplikasi yang dibangun mampu mendukung verifikasi keaslian produk secara cepat, aman, dan akurat sehingga membantu mengurangi risiko pemalsuan dan meningkatkan kepercayaan pelanggan.

The increasing demand for Gotrock jeans products has been accompanied by the emergence of counterfeit products that harm both producers and customers. The similarity between genuine and counterfeit products makes it difficult for customers to verify product authenticity, while manual verification processes are considered inefficient. This study aims to design and develop a QR Code-based product authenticity verification application using the ECDSA Algorithm . The system was developed using the Prototype method, which consists of requirement analysis, design, evaluation, implementation, and testing stages. Data were collected through observation, interviews, and literature studies. The application was developed as a web-based system using PHP and MySQL. In its implementation, the product ID is processed using ECDSA to generate a digital signature, which is then converted into a QR-Code and attached to the product. Customers can scan the QR-Code using a smartphone, after which the application verifies the digital signature to determine the product's authenticity status in real time. The testing results show that White Box Testing validated the generate and verify signature functions, Black Box Testing confirmed that all application functions operated as expected, and User Acceptance Testing (UAT) achieved acceptance rates of 96% from administrators and 93.8% from customers. The developed application is capable of supporting product authenticity verification in a fast, secure, and accurate manner, thereby helping to reduce the risk of counterfeiting and increase customer trust.