Python Encryption/Decryption CLI Script Creation

I have a simple Python script that I would like to share with friends but I do not want to share the main file, rather, I would like to make another Python end for the users without having to share my script. The secondary Python script should be a command-line interface (CLI) that allows users to both encrypt and decrypt data. It needs to work with both text data and files. Ideally, the script should connect to a free API alternative for encryption, one that's suitable for novices in encryption.

Skills and Experience:
- Proficient in Python programming
- Experience in creating command-line interface scripts
- Familiarity with encryption/decryption techniques and APIs
- Understanding of data types and file handling in Python
- Ability to write secure and efficient code