The answer to your question is OAEP but I feel like I'd still be doing you a disservice there because I am convinced the answer ought to be box/secretbox or Fer

The answer to your question is OAEP but I feel like I'd still be doing you a disservice there because I am convinced the answer ought to be box/secretbox or Fernet or AESGCM maybe -- but that hinges on my question about asymmetric cryptography which is elsewhere in the thread :)