import base64



class SimpleEncrypt:
    def __init__(self, key):
        self.key = key

    def do_encode(self, bs):
        tmp = bytearray(self.key.encode())
        i = 0
        while i < len(bs):
            for j in range(len(tmp)):
                if i >= len(bs):
                    break
                bs[i] = bs[i] ^ tmp[j]
                i += 1

    def encode_string(self, s):
        data = bytearray(s.encode())
        self.do_encode(data)
        return base64.b64encode(data).decode()

    def decode_string(self, s):
        data = bytearray(base64.b64decode(s))
        self.do_encode(data)
        return data.decode()

SE3 = SimpleEncrypt(key="entservice")