postcards.py 文件源码

def _decode(self, key, enc):
        dec = []
        enc = base64.urlsafe_b64decode(enc)
        for i in range(len(enc)):
            key_c = key[i % len(key)]
            dec_c = (enc[i] - key_c) % 256
            dec.append(dec_c)
        return bytes(dec)