cleanup login protocol, add common functions for encryption/decryption
Merge pull request #1 from haynesma/master

lfads
Finalize login and fix issues that came up, use nonces to verify shared key
Merge branch 'master' of github.com:atironati/network-security

Conflicts:
	Final-Project_SecureIM/common.py
Both LOGIN and LIST protocols now work
Add mark as a user
Merge pull request #2 from atironati/master

blah