"Failed to parse JSON object as TDLib request: Wrong padding length" When tried to login

[VenkatTeja]

File "/app/index.py", line 17, in
tg.login()
File "/usr/local/lib/python3.8/site-packages/telegram/client.py", line 439, in login
result.wait(raise_exc=True)
File "/usr/local/lib/python3.8/site-packages/telegram/utils.py", line 41, in wait
raise RuntimeError(f'Telegram error: {self.error_info}')
RuntimeError: Telegram error: {'@type': 'error', 'code': 400, 'message': 'Failed to parse JSON object as TDLib request: Wrong padding length', '@extra': {'request_id': 'updateAuthorizationState'}}

Code is running in docker!

Thank you

[alexander-akhmetov]

Hi,

On which authorisation state does it fail? It should print it to the logs.

[CatCoderr]

I have the same problem, here is logs: https://pastebin.com/qAUQr5Ck

[alexander-akhmetov]

I see, thanks for the logs. Probably it's related to the encryption key (parameter database_encryption_key).

While it's not fixed in python-telegram, can you try to make the database encryption key string longer? Probably you'll need to remove existing tdlib database. By default python-telegram keeps it in /tmp/.tdlib_files/

tg = Telegram(
    database_encryption_key='...',
)

[steven-chau]

I have the exact same problem! Same error. Same stacktrace.

I have tried a long database_encryption_key and a short one. No luck :(

Perhaps the protocol has changed? The underlying tdLib library needs to be upgraded?

[jonasborges]

I see, thanks for the logs. Probably it's related to the encryption key (parameter database_encryption_key).

While it's not fixed in python-telegram, can you try to make the database encryption key string longer? Probably you'll need to remove existing tdlib database. By default python-telegram keeps it in /tmp/.tdlib_files/

tg = Telegram(
    database_encryption_key='...',
)

It seems to be the parameter name being sent.

The example provided by tdlib uses key as parameter for checkDatabaseEncryptionKey messages.

{'@type': 'checkDatabaseEncryptionKey', 'key': '...'}

While python-telegram is using encryption_key.
The documentation also mention encryption_key.

So, I made it work by changing the key name from encryption_key to key. I'm not sure if this is the proper solution but works for now.

[alexander-akhmetov]

The example provided by tdlib uses key as parameter for checkDatabaseEncryptionKey messages.

Hm, interesting! I'm not sure if it's a mistake or they are interchangeable. I will try to look into that.

I also found that in td_api.tl encryption_key has type bytes and in the documentation it is string. They mentioned in one of the issues that bytes should be sent as base64 encoded string. The error original error message (Wrong padding length) is also related to base64.

With base64 encoded string it seems to be working, but I don't know yet how to check if tdlib is using the correct and decoded from base64 key, or just the passed string:

    def _send_encryption_key(self) -> AsyncResult:
        logger.info('Sending encryption key')

        key = self._database_encryption_key
        if isinstance(key, str):
            key = key.encode()

        data = {
            '@type': 'checkDatabaseEncryptionKey',
            'encryption_key': base64.b64encode(key).decode(),
        }

        return self._send_data(data, result_id='updateAuthorizationState')

I asked a question in tdlib repository about base64 and difference between key and encryption_key: tdlib/td#970

---

Can somebody try to use the default key from the python-telegram examples (database_encryption_key='changeme1234') and an empty key (database_encryption_key=''), please?

[alexander-akhmetov]

I asked a question in tdlib repository about base64 and difference between key and encryption_key: tdlib/td#970

Yes, it has bytes type and should be encoded using base64, I'll make changes to python-telegram.

While it's not fixed, you can try to do it on your side: use a different key with a different length or encode encryption key using base64 and pass it to Telegram:

import base64

...

encryption_key = base64.b64encode(b'secret').decode()

tg = Telegram(
    ...
    database_encryption_key=encryption_key,
)

[alexander-akhmetov]

Released 0.12.0 (both the package and the docker image), if you still see the problem, please re-open the issue