Do Bigger Grid Sizes Mean Better Passwords? 3x3 vs. 4x4 Grid Sizes for Android Unlock Patterns

Abstract

This poster-abstract presents the results of an IRB approved survey studying Android unlock pattern choices as compared between two grid sizes (3x3 and 4x4); the smaller grid size is the current standard. We recruited 80 participants who chose both patterns for themselves and guesses of others’ patterns, collecting 491 3x3 and 504 4x4 patterns. Patterns were analyzed using several metrics including: repetition rates, pattern recall, pattern compromises, node length, stroke length, common pattern forms, and the start/end point frequency. Pattern recall and compromises varied between grid sizes; however, the variations in patterns between grid sizes, generally, are less pronounced with many 4x4 patterns simply being embedding of 3x3 patterns. Overall, 3x3 and 4x4 patterns chosen by humans have the same basic properties, and increasing the grid size to 4x4 would likely not change behavior despite significantly increasing the number of available patterns for 4x4 grid size from 389,112 to 4,350,069,823,024