CS6001-AES

Authors: Quincy Conduff, Scott Payne, Colin Conduff

Software requirements

1. Python version 3 (~3.5 should be fine)
2. Tkinter version 8.5 (should be included with python)

Usage: Steps for using the GUI for file encryption and decryption

1. python3 aes_gui.py
2. Select desired key length by clicking a radio button next to 128, 192, or 256.
3. Click Gen. Key button
4. Select AES mode
   a. For ECB AES mode, select ECB radio button
   b. For CBC AES mode, select CBC radio button and click Gen. IV button
5. In File Path textbox: enter in full file path to file that you would like to encrypt
   Example: /Users/username/Desktop/test.png
   Note: If Out Directory input is empty, the program will create an encrypted file with .enc appended to the end (e.g. test.png.enc).
6. Click Encrypt button
7. After encryption has finished, change File Path input to the file path to the encrypted file.
   Example: /Users/username/Desktop/test.png.enc
   Note: If Out Directory input is empty, will overwrite original input file (e.g. test.png).
8. Click the Decrypt button

Optional: Provide configuration file containing mode and key information

1. python3 aes_gui.py
2. In File Path textbox: enter in full file path to file that you would like to encrypt
   Example: /Users/username/Desktop/test.png
   Note: If Out Directory input is empty, the program will create an encrypted file with .enc appended to the end (e.g. test.png.enc).
3. Select checkbox next to Config textbox.
   Note: This disables entry into Key and Initialization Vector fields.
4. In Config textbox: enter in full file path to file that has JSON configuration settings.
   Example: /Users/username/Desktop/test.png.conf
   Note: If Config input is empty, the program will create a configuration file with given settings upon Encryption. The file path for the Config will be the input File Path with '.conf' appended (e.g. test.png.conf).
5. Click Encrypt button
   Note: If the Key or Initialization Vector fields are empty, then they will be generated automatically when necessary.

Note: Decrypt will fail when Config is enabled, but no Config file is found or the file is ill formatted.

Example Config

{
  "mode": "ecb",
  "key-size": 16, // key size in bytes
  "key": xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx, // key in hex string format (leading 0x can be omitted)
  // "iv": xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx, not necessary for ecb mode
}

To run unit tests for AES encryption and decryption:

python3 aes_test.py

This project includes the following files:

aes_impl.py

Functions implementing core AES encryption and decryption functionality.

aes_io.py

Sample I/O handling.
Opens files and encrypts them in byte sized chunks, appending results to output file.

aes_test.py

Unit tests for the encryption and decryption AES functions on files and string messages.

aes_gui.py

Encryption/Decryption GUI implementation.
Takes file path, key, and output directory as input.
Clicking buttons will result in actions, with information logged in text window and bottom of window about errors or successes.

Buttons

Encrypt: 
  Takes the file path and key and encrypt the file with that key, placing it within the desired output directory.
  
Decrypt:
  Takes the file path and key and decrypts the file with that key, placing it within the desired output direcory.
  
Gen. Key:
  Generates a key for the user, in the event they don't want to provide their own during ecryption.

Gen. IV:
  Generates an initialization vector for use during CBC AES mode.

Text Fields

File Path:
  Text field for user to provide file path of the file they want to encrypt or decrypt.
  
Key:
  Text field for user to provide the key needed for decryption or the key phrase they'd like to use for encryption.
  This will need to use an appropriate hasing function to convert human-friendly phrases into correct byte length keys.
  
Out Directory:
  Text field for user to provide the desired directory for the resulting encrypted/decrypted file to be placed in.
  Will default to same directory as the file given to be encrypted/decrypted.

Radio Buttons

Provide options for key sizes and AES modes.

aes.ico

Icon image file for thumbnail of GUI.

test_img.jpg

Temporary image file used in aes_io.py to test file I/O.

helper_functions.py

Provides functions for generating keys and initialization vectors, as well as performing number conversions.