The Input System Of Password Protection For Shoulder-Surfing By Using Sudoku Puzzle

In this paper we propose a new password input system against shoulder-surfing and random attack. This input system exploits the method of number arrangement applied in Sudoku Puzzle. Numbers appeared in row and column in Sudoku Puzzle are all unique. We applied this characteristics of Sudoku number placement to hide the user password. So even if a shoulder surfer observes our password input process wholly, it is not possible to get the user's password it self. If input table is of grid, the probability that user password is identified is about 0.007, which is believed to be practical. We show that the probability that random attack works is about . Finally we have conducted the usability test with five experimenters, which is summarized in the final chapter.