What is important is more a library where the easiest thing to do is correct, and making it really hard to make mistakes. Make the encrypt/decrypt function the

What is important is more a library where the easiest thing to do is correct, and making it really hard to make mistakes. Make the encrypt/decrypt function the only public api, with as few args as possible. Manage IVs under the hood so the user can't accidentally reuse them. That's the approach taken by NaCl, and arguably the only one worth considering.