TY - Front. Comput. Sci. A1 - Lip Yee POR, Chin Soon KU, Amanul ISLAM, Tan Fong ANG T1 - Graphical password: prevent shoulder-surfing attack using digraph substitution rules Y1 - 2017-12-01 JF - Frontiers of Computer Science JO - Front. Comput. Sci. SP - 1098 EP - 1108 VL - 11 IS - 6 UR - https://journal.hep.com.cn/fcs N1 - 10.1007/s11704-016-5472-z ER -