colinneagle writes with word of work done by researchers at Arizona State University, Delaware State University and GFS Technology Inc., who find that the multiple-picture sequence security option of Windows 8 suffers from various flaws -- some of them specific to a password system based on gestures, and some analogous to weaknesses in conventional passwords entered by keyboard.
"The research found that the strength of picture gesture password has a 'strong connection' to how long a person spent setting up that password gesture. The most common gesture combination is three taps, meaning it took about 4.33 — 5.74 seconds to setup. Passwords with two circles and one line took the longest average input time of about 10.19 seconds. After studying why people choose certain categories of images, the most common gesture types and direction patterns in PGA passwords, the researchers developed an attack framework that is 'capable of cracking passwords on previously unseen pictures in a picture gesture authentication system.'"