How are lockbox and attr_encrypted different from each other?

I'd like to store users' API keys in my database. Lockbox was previously suggested to me, but I just came across attr_encrypted gem and they look like they achieve the same results to me.

I'd like to know usage aside, are they any different? I'm leaning towards attr_encrypted for ease-of-use, but would like to hear some professional opinion since I'm storing sensitive data.