Code for key generation, key sharing and key retrieval
* `key_gen.py` generates public a private key and saves them to file. It raises some stranges errors, but it does its job.
* `key_sharing.py` shares key. If it does not work, please, use Python 2 to run this.
* `key_retrieval.py` retrieves shared key. If it does not work, please, use Python 2 to run this.
*`key_sharing_func.py` almost the same as `key_sharing.py`. I tried to put key generation and key encryption together. But `key_gen.py` was not able to find this file in the current file structure.
