#!/usr/bin/env python
from hashlib import md5
from uuid import uuid4

passwortdb = {}   # leeres Dictionary

def get_salt():
    return uuid4().hex[:4]  # 4-stelliges Salt

def split_at_dollar(s):
    return s.split("$",1)  # Strings vor/hinter erstem $

def new_password():
    username = input("username: ")
    password = input("password: ")
    passwortdb[username] = md5(password.encode("utf-8")).hexdigest()

def list_db():
    for username in passwortdb.keys():
        print ("%s:%s" % (username, passwortdb[username]))

def login():
    username = input("username: ")
    password = input("password: ")
    if username not in passwortdb.keys():
        print ("login failed.")
        return
    pass_in_db = passwortdb[username]
    if md5(password.encode("utf-8")).hexdigest() == pass_in_db:
        print ("login ok.")
    else:
        print ("login failed.")

while True:
    cmd = input ("Befehl (new, login, list)? ")
    if   cmd == "new":
        new_password()
    elif cmd == "login":
        login()
    elif cmd == "list":
        list_db()