<![CDATA[Abstrak— Captcha merupakan salah satu cara memberikan akses internet yang aman dari serangan bots. Captcha (Completely Automated Public Turing Test To Tell Computers and Humans Apart) merupakan sebuah challenge response test yang digunakan untuk membedakan manusia dan robot (bots). Namun seiring perkembangan waktu, telah berkembang serangan otomatis yang berhasil membobol beberapa jenis Captcha. Oleh karena itu, pada penelitian ini dikembangkan Captcha berbasis gambar dengan metode autentikasi yang berbeda. Autentikasi Captcha dilakukan dengan menerapkan algoritma Flood Fill. Dalam implementasinya, dapat disimpulkan bahwa algoritma Flood Fill berhasil diimplementasikan pada autentikasi modul Capthca berbasis gambar. Telah dilakukan juga pengumpulan sampel data dan didapatkan hasil 77.4% responden merekomendasikan penggunaan Captcha yang telah dibangun. Kata Kunci— Autentikasi, Captcha, Captcha Berbasis Gambar, Flood FillAbstract— Captcha is one of many methods to secure internet from bots attack. Captcha (Completely Automated Public Turing Test To Tell Computers and Humans Apart) is a challenge response test which used to differentiate human from bots. However after the times flow, some hackers had successfully made an automatic bots to break captcha. Therefore, in this particular research, formed an imaged based captcha that uses different method of authentication. Flood Fill algorithm will be used as authentication method. In the implementation, Flood Fill algorithm has been successfully implemented as an authentication method in image based captcha. After that, data samples have been collected and the result shows 77.4% respondents agreed to recommend using the Captcha that has been developed. Keywords— Authentication, Captcha, Image-based Captcha, Flood Fill]]>
