Abstract:As the most widely used graphical password scheme on mobile terminals, Android unlock pattern (AUP) is not quite uniformly distributed in its theoretical password space when in practical use, which exposes a tremendous hazard that can be easily exploited by the attacker to expedite dictionary attack or violence crack. To address this issue, this paper proposes a new scheme, Android-unlock-pattern based on random point exclusion (AUP-RPE), which helps the user to avoid habitual choices by the new interface arrangement. In addition, patterns in real-life use are collected by performing a large-scale user study with over 1 100 people. Modeling based on those patterns shows the entropy of AUP-RPE increases over 3 orders of magnitude than the entropy of AUP, which means that AUP-RPE has a much stronger security.