Cryptography Project

I am working on a cryptography project I reached a step where my code can encrypt a file, txt file and print its size. I am trying now to be able to encrypt a file of any size and print how long it takes to do so. I am attaching my code which has the progress. A description of my project: An overview on the AES encryption, explaining how it works block by block. · What are the main differences between AES 128, 192, and 256. · Is AES a symmetric or asymmetric encryption algorithm? · Compare the ECB and CBC modes of encryption. · What are the main applications of AES? · How is the AES encryption algorithm used in secure file transfers? · Screenshots of the execution of your codes. · The final version of your AES-CBC-256 encryptor /decryptor code .