VAP code: A secure graphical password for smart devices. - Saiful Azad; Musfiq Rahman; M. S. A. Noman Ranak; B. M. F. Kamal Ruhee; N. Nourin Nisa; Nazrul Kabir; Arafatur Rahman; Jasni Mohamad Zain (Comput. Electr. Eng., 2017)