I first learned about lockpicking during highschool. A locksmith introduced me to the basic understanding of how most locks work and how to break them. So, I tried it again with a transparent training padlock. It seems easy but on real locks, it really hard and needs patience as you can’t see the pin tumbler. Instead of using lock picking toolset, bending your own paper clip is more challenging.
For more exploration, I found this documentation is excellent and quite detailed, http://www.blurofinsanity.com/mit/lockpick.html. Chapter 9 is very interesting.
Is it legal to do this or owning the lockpicking toolset? Different country has different laws for this. There are ethical code that applied among lockpicking communities. It’s even considered as an art!
The other thing I learned from lockpicking is security on obscurity will not enough to protect people.