python註冊登錄的實現--low版

#!/usr/bin/env python     
# -*- coding:utf-8 -*-      
import hashlib
import getpass
import sys
def login(name,password):
    file=open("user",'r',encoding='utf-8')
    for user in  file:
        list=user.split(":")
        if list[0] == name and list[1] == password:
            file.close()
            return True
        else:
            file.close()
            return False


def reg(name,password):
    file=open("user",'a',encoding="utf-8")
    info=name+":"+password+"\n"
    file.write(info)
    file.close()


def main():
    global user,pwd
    chonice=input("-----------（選擇）1登錄/2註冊--------：")
    if chonice == "1":
        obj=hashlib.md5()
        user=input("輸入您的用戶名：")
        pw=getpass.getpass("輸入您的密碼:")
        obj.update(bytes(pw,encoding='utf-8'))
        pwd=obj.hexdigest()
        for times in range(3):
            if login(user,pwd) == True:
                print("登錄成功！！")
                break
            else:
                print("第%d次錯誤!!!"%(times+1))
                if times == 2:
                    print("已超過3次，用戶已禁止登錄！！")
    elif chonice == "2":
        reg(user,pwd)
    else:
        print("選擇錯誤退出！！")
        sys.exit(0)
main()