simulation of key management and distribution.
1.python3
2.flask:pip3 install Flask
1.run the Certificate Authority server: python3.6 CA.py
runs on port 5000
2.run first client python3.6 client.py -p 3000 -op 4000
2. run second client python3.6 client.py -p 4000 -op 3000
-p
: client's port
-op
: other client's port