The short version is by following the guidelines, a FaceChallenge offers three (3) levels of security:
~~ A simple 3×3 matrix is a 1 in 9 possibility anyone but you can access. Said another way, 8 out of 9 times the intruder will be wrong. Moreover, each failed attempt increases the time delay before re-try. Plus — all new faces appear in the next FaceChallenge.
~~ A 4×4 matrix with two faces per panel and two panels increases the odds against unauthorized access to 1 in 14,400. Here again the increasing time delay to re-try and the fresh faces in the upcoming FaceChallenge add to the difficulty of overcoming FaceGuard security.
~~ A 4×6 matrix with three faces per panel and three panels creates odds of 1 in 8 billion a hacker can break into your FaceGuard app. The increasing time delay and new face array follows every failed attempt. Essentially, guessing a way past FaceGuard security can be made very difficult.