Pin tumbler locks are the most common locks found on the front doors of home.Most common pin tumbler locks can be picked thanks to slightly loose fits of the pins and tiny manufacturing defects.
source/image(PrtSc): Stuff Made Here
Each individual lock pin is actually made up of a set: a key pin and driver pin. The key to a lock that cannot be picked is finding a lock that is unique and rare. When the break between each set of key and driver pins aligns with the lock turning mechanism, also called the shearline, the lock turns and opens.
In this video Stuff Made Here Youtube channel designs and builds a unpickable lock that prevents the pins from being set in unlocked position one by one, he does this by locking the all pins in whatever position they are set and preventing further manipulation when the cylinder.
How hard could it be to make an unpickable lock? Turns out pretty flippin hard. After I recovering from the mental and physical turmoil of getting this thing made I called up a locksmith to see if they would be able to pick it. A fun time for all involved.//Stuff Made Here