Putting together primitives in a way that doesn't have subtle flaws is not trivial. Many a standard have been vulnerable due to this. You think you can do bette

Putting together primitives in a way that doesn't have subtle flaws is not trivial. Many a standard have been vulnerable due to this. You think you can do better? We do have simple, well engineered, and sometimes even probably secure constructions. Look at libsodium if you want a decent example of what a modern library looks like. And stay away from anything that mentions the words NIST, FIPS, or any other government acronym. You aren't going to find modern, well-engineered, simple crypto in anything catering to that market. It's always hideously overcomplicated and rife with chances for bugs.