[python] Login System with MD5 Encryption

[Gonzalez]

#!/usr/bin/env python
#Author: s3my0n
#Base Idea: 1R3N1CU5

#Comment: If you feed invalid type of database, the program will break ^^ be nice

import sys
from hashlib import md5

class UserManagement(object):
    def __init__(self, pathtodb):
        self.pathtodb = pathtodb

    def readDatabase(self):
        try:
            self.fopen = open(self.pathtodb, 'r+') #tryes to open path
        except(IOError):
            print '\n [-] Could not open %s to read/write' % (self.pathtodb)
            sys.exit()
        pares = [i.strip() for i in self.fopen.readlines()] #stripping '\n' newline
        db = {}
        for i in pares:
            pare = i.split(':') #this returns [user, pass] out of 'user:pass'
            db[pare[0]] = pare[1]
        self.database = db

    def encryptPassword(self, text): #My nifty md5 hash maker
        m = md5()
        m.update(text)
        en_text = m.hexdigest()
        return en_text

    def userLogin(self, user, password):
        if self.database.has_key(user):
            if self.database[user] == self.encryptPassword(password): #encrypting password to md5 hash 
                print '\n [+] Access Granted!'                   #and comparing it to the database's hash
            else:
                print '\n [-] Invalid password for %s' % (user)
        else:
            print '\n [-] Invalid username'

    def userRegister(self, user, password):
        if self.database.has_key(user):
            print '\n [-] User already exists'
            return
        towrite = '%s:%s\n' % (user, self.encryptPassword(password))
        self.fopen.write(towrite)   #writing 'user:pass' to database

def about():
    a = '''
 #########################
 #                       #
 # Author: s3my0n        #
 # Idea: 1R3N1CU5        #
 #                       #
 # For Intern0t.net !!!  #
 #                       #
 # Experiment and Learn  #
 #                       #
 #########################
 '''
    return a

def rules():
    r = '''
 1: Register new user
 2: Login with existing user
 3: Exit the program
 '''
    return r

def register():
    try:
        u = raw_input('\n Enter new username: ')
        p = raw_input('\n Enter new password: ')
    except (KeyboardInterrupt, IOError):
        print '\Going back to main menu'
        return
    mng.userRegister(u, p) #adding new user
    mng.readDatabase() #updates database

def login():
    try:
        u = raw_input('\n Username: ')
        p = raw_input('\n Password: ')
    except (KeyboardInterrupt, IOError):
        print '\n [*] Going back to main menu'
        return
    mng.userLogin(u, p)

def main():
    print rules()
    while True:
        try:
            command = raw_input('\nWhat would you like to do?: ').strip()
        except (IOError, KeyboardInterrupt):
            print '\n [*] See ya later aligator'
            sys.exit()

        if command in '123':
            if command == '1':
                register()
            if command == '2':
                login()
            if command == '3':
                print '\n [*] BYe..'
                sys.exit()
        else:
            print '\n [-] Invalid command'

if __name__=='__main__':
    while True:
        try:
            path = raw_input('\nPlease specify path to user database: ')
        except (KeyboardInterrupt, IOError):
            print '\n [*] Aborted'
            sys.exit()
        break
    global mng #this is so all functions can access UserManagement class
    mng = UserManagement(path) #on this assignment __init__ gets path as pathtodb
    mng.readDatabase() #reads database

    print about()
    main() #starting main function