Problem decoding token

Hello, thanks for making pyjwt!

I’ve been trying to use it in my Django application, however, something weird is happening: I can’t decode the token!

This is how I’m creating the token

token = jwt.encode({
    'user_id': user.id
}, key='secret', algorithm='HS256')

And creating a token with user_id: 1 gives me this token b'eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyX2lkIjoxfQ.J_RIIkoOLNXtd5IZcEwaBDGKGA3VnnYmuXnmhsmDEOs', however it says invalid signature in https://jwt.io/ for some reason.

Trying to decode my token in the server throws this error:

Traceback (most recent call last):
  File "/home/andres/venv/zyru/lib/python3.6/site-packages/jwt/api_jws.py", line 170, in _load
    header_data = base64url_decode(header_segment)
  File "/home/andres/venv/zyru/lib/python3.6/site-packages/jwt/utils.py", line 42, in base64url_decode
    return base64.urlsafe_b64decode(input)
  File "/home/andres/venv/zyru/lib/python3.6/base64.py", line 133, in urlsafe_b64decode
    return b64decode(s)
  File "/home/andres/venv/zyru/lib/python3.6/base64.py", line 87, in b64decode
    return binascii.a2b_base64(s)
binascii.Error: Incorrect padding

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/andres/Code/Python/zyru-api/members/schema.py", line 41, in get_user
    decoded = jwt.decode(token, 'secret')
  File "/home/andres/venv/zyru/lib/python3.6/site-packages/jwt/api_jwt.py", line 70, in decode
    payload, signing_input, header, signature = self._load(jwt)
  File "/home/andres/venv/zyru/lib/python3.6/site-packages/jwt/api_jws.py", line 172, in _load
    raise DecodeError('Invalid header padding')
jwt.exceptions.DecodeError: Invalid header padding

Why is the exception happening?

Thanks a lot!

[vimalloc]

This isn’t right:

decoded = jwt.decode(token, 'secret', 'utf-8')

You want to create the token like such:

# The decode call here doesn't decode the jwt, it converts the encoded jwt from
# a byte string to a utf-8 string.
data = {'foo': 'bar'}
encoded_token = jwt.encode(data, 'secret', 'HS256').decode('utf-8')

and decode it like:

decoded_token = jwt.decode(encoded_token, 'secret', algorithms=['HS256'])

[vimalloc]

Try decoding the token to utf-8:

jwt.encode(data, secret, algorithm).decode('utf-8')

In jwt.io, you need to get rid of the b'' part of the string. That indicates that it is a byte string, and is not actually part of the token.