Vibrainput: two-step PIN entry system based on vibration and visual information

Current standard PIN entry systems for mobile devices are not safe to shoulder surfing. In this paper, we present VibraInput, a two-step PIN entry system based on the combination of vibration and visual information for mobile devices. This system only uses four vibration patterns, with which users enter a digit by two distinct selections. We believe that this design secures PIN entry, and allows users to easily remember and recognize the patterns. Moreover, it can be implemented on current off-the-shelf mobile devices. We designed two kinds of prototypes of VibraInput. The experiment shows that the mean failure rate is 4.0%; moreover, the system shows good security properties.