####Secure Messaging for Windows Phone 8.1

CS 460 Spring 2014
Feraas Khatib - khatib3
Gustavo Frankowiak - frankow1

Features:

• AES ECB PKCS7 Encryption
• NFC Functionality
• Full user system with friend management
• Easily add friends by tapping phones together and get a random generated 256 character encryption key for a secure chat session
• All data is stored fully encrypted in a remote database
• All user data (usernames, passwords, friend requests etc..) is sent fully encrypted and over SSL
• No data is ever sent plaintext over the internet
• Each friend has a different encryption key that is used for that session
• Start a secure chat session using the internet and get a unique key or for more security just tap phones together and get a random generated key that is never sent over the internet

Future Enhancements:

• Clean up and debug code. Everything works fine if used exactly as intended but there is very little handling for user error.
• Enable saving sessions and running in the background so that users can tap and generate a key and save that key for a long time
• Add secure message storage so that messages are not deleted after the app is closed
• Add SSL protection for messages not only user data
• Increase security for sessions established without using NFC

Compatible with: Visual Studio 2013 and Windows Phone 8.1 only.

Project Notes:

• Anything with .xaml extension is just the UI and its associated code file can be found by adding .cs to the file name (i.e. LoginPage.xaml is the UI with backend code LoginPage.xaml.cs)
• AppServices.cs has the universally used variables and functions including ones for encrypting and decrypting data and sending/receiving data
• In order to run the code on the Windows Phone 8.1 emulator on a computer Visual Studio 2013 RC2 along with the Windows phone 8 SDK running on Windows 8.1 Pro is required.
• 3 external libraries/API's where used in development. The .dll files can be found in the Tap Chat/Libs folder. If the code does not compile initially it is most likely because the references to these libraries need to be updated. They libraries used are:
  1. Newtonsoft JSON: Library for serializing data objects to and from JSON for easy sending and receiving of data.
  2. App42Windows: Back end service provided by shephertz for managing user accounts and friends. This essentially handle's the back end database for storing user accounts and friend management.
  3. AppWarpWinRT: This is another back end service provided by shephertz that is used to send the messages between users.