Sunday, 13 November 2011

4 reasons why I love Android pattern on screen lock

I'm waiting for the new Android Ice Cream Sandwich release to be available for my Samsung Galaxy S II. Only then I will be able to try the new Face Unlock feature (though it's been proved not to be that safe).

In the meanwhile I will go through why I simply love the visual pattern on screen lock in Android phones!

I like it for different reasons:

It's a different way of thinking of a lock and of exploiting the capabilities of a new media - too often we have used and abused the same PIN interface of physical locks.

This new concept does not reduce security, though it may seem so.
In fact, it is safer - at least in theory!

Case1: Digit lock.
You've got 4 digits. Each of them can be chosen within a set of 10 different possibilities (0 to 9).
The possible combinations are therefore 104 = 10.000.

Case2: Visual lock
In this case you have just 9 spots and you can't go through them more than once. Yet you have no fixed length, which means you might have a 2-spot combination as well as a 9-spot one.
Let's simplify our job, let's just consider 9-spot combinations, assuming any is equally possible. Then the possible combinations are waaaay more than the cipher lock: there are 9 spots to choose among, then 8 to connect the chosen spot with, then 7 and so forth.
Considering a 9 spot path, all the possible options are: 9! = 362.880
(Yes, yes, I'm aware this is not really the case, for you have to draw a path, but still it's one order of magnitude bigger than the PIN option.)

I like seeing touch devices being disconnected from any cultural (meaning "literate") background - it takes technology a step forward to broader accessibility and it does not suggest "accessible = unsafe". :)
There's no need to be literate to keep things safe.

And last (but not least)
Being a visual person, I often remember codes and numbers based on the path my finger draws while entering them - and that is a common thing, since humans are visual animals, that's how we're wired. :)


  1. The number of combinations are supposed to be even a little higher than what you report (
    Yet, although I love pattern lock too, it is vulnerable to a quite simple attack. Just looking carefully to the slight greasy trail that results from recurrent and frequent use of the unlocking pattern with respect to the rest of the screen, where fingerprints accumulate in a more random and less systematic manner. Not to mention that people tend to choose simple patterns (hence, faster to perform), like L- or U-shaped curves, a clue that could facilitate the detection of that faint, but definitely present, trail on the mobile screen.

  2. Your calculations are not correct.
    4-digit PIN gives 10.000 combinations
    4-points pattern gives 1624 combinations.

    A 9-digit PIN gives combinations.
    A 9-points pattern gives 389.112 combinations.

    Many links in the web may give the math analysis, and a good one is here: and here:


    1. Maybe I could understand having a possibility of 389 combinations, but I haven't determined how to utilize the remaining 0.112 posibilities. Perhaps, your math isn't accurate either, because you haven't determined the actual whole number combinations that a pattern lock will permit; instead you use a hypothetical with a remaining decimal. Besides, it doesn't really matter, anyhow.

      The phone lock is only good as the security that prevents your phone from being physically stolen; otherwise, all the screen lock is really doing is keeping out nosy people in the vicinity of the phone while you're not looking.

      If a hacker/thief wants to get into your phone, the phone lock security will be easily hacked, regardless the ratio of possibilities.

      It's a no brainier, your eyes are the best locks you have.


    2. Not sure if you're trolling or not, but he means 389112 (as in 389 thousand).