I want to install an applock to my android phone. I have found a great one, but its only drawback is that is supports only 4 digits pins, whereas other similar apps support with maybe 10 or more.
I know in password setting, the more chars the merrier. But is this the case with applocks? do 4-digit pins offer a reasonable level of security? And if yes, under which case?
From a technical point of view 4 digit pins alone (I.e with no attempt restriction / timed lockout) offer no security at all. They can be brute forced in under a second on any vaguely modern device. Saying that in this case the difference is of more or less no benefit.
Security is about far more than key entropy. You should realise against a technical opponent every app locker I've seen for android or IOS offers zero security benefit. The underlying data is still just as accessible - it's basically just stopping you launching the shortcut.
What are you trying to defend against?
If you're hoping to stop a skilled opponent (law enforcement, determined criminal etc) from accessing certain applications I would suggest you look for a better strategy than an app locker.
If you're trying to stop your mum, child or friends from posting to your Facebook when then have your phone for two minutes to view a photo I'd argue that they are unlikely to make it past an entirely random 4 digit number assuming no related technical skills and Googling "How to get around [name of app locker] doesn't yield anything useful.
