Overview:

We implemented modules that can do one of two things:
   1. Encode messages onto images and post the images to Twitter; read the
      image from Twitter and decode the message. (Zach)
   2. Encrypt messages using RSA and encode them on an image; read the
      image and decode/decrypt the message. (Nick)

We would have integrated these, but due to a miscommunication and lack of
time, they are separate features.

Usage:

1.

2. To run the RSA encryption and encoding, you first need to generate a
   keypair. To do this, run
   
     python genkeys.py pub_file priv_file

   to save public and private keys to their respective files. To encode
   the message, run

     python watermark.py encode plain_img out_img in_txt pub_key

   This will encrypt in_txt with pub_key and encode it onto a copy of
   plain_img and save the resulting image to out_img.

   To decode the message, run

     python watermark.py decode encoded_img out_file priv_key

   This will decode the message from encoded_img, decrypt it with priv_key,
   and save it to out_file.

Libraries:
   PIL 1.1.7
   PyCrypto 2.5