FIPS 140-2 is a set of rules made by the US government to make sure that organizations that use cryptography to protect their computer systems and the information in them are doing it correctly.
Imagine you have a secret diary where you write your stories, and you don't want anybody else to read them. You make a lock on the diary to protect it.
Now, think about computers and smartphones — they are like your diary, where you store your pictures, videos, and messages. But instead of a lock, you use "cryptography," a fancy word that means turning data into a code language that nobody else understands.
So, FIPS 140-2 is like a set of rules, like instructions, that tell companies how to make the lock for your diary (cryptography) in the best way possible, so nobody can break it and read your secrets.
These rules check the level of security of the system, like how strong your diary lock is, and then give the system a score from 1 to 4. FIPS 140-2 only accepts systems that score 2 or higher, which means they are very secure, like the lock on Fort Knox.
This way, FIPS 140-2 makes sure that only the best and most secure systems are used by organizations to store your information and keep your secrets safe.