db1 = {

    'michael': 'e10adc3949ba59abbe56e057f20f883e',

    'bob': '878ef96e86145580c38c87f0410ad153',

    'alice': '99b1c2188db85afee403b1536010c2c9'

}

def login1(user, password):

    if not user in db1:

        raise ValueError('用户未注册')

    md5 = hashlib.md5(password.encode('utf-8')).hexdigest()

    return md5 == db1[user]

def get_md5(s):

    return hashlib.md5(s.encode('utf-8')).hexdigest()

class User(object):

    def __init__(self, username, password):

        self.username = username

        self.salt = ''.join([chr(random.randint(48, 122)) for i in range(20)])

        self.password = get_md5(password + self.salt)

db2 = {

    'michael': User('michael', '123456'),

    'bob': User('bob', 'abc999'),

    'alice': User('alice', 'alice2008')

}

def login2(username, password):

    if not username in db2:

        raise ValueError('用户未注册')

    user = db2[username]

    return user.password == get_md5(password + user.salt)