Convert JWT token created by Java JWT in python

I have received a JWT token created by a java program using jjwt module. Now, when I try to verify the token using pyjwt, it throws exception.

import jwt token
token='eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMDAiLCJyb2xlcyI6IkJVU0lORVNTVVNFUiIsIm1vZGUiOiJzdG9yZWFwcCIsImlhdCI6MTQ5NDg1ODk4MCwiZXhwIjoxNDk0ODY0OTgwfQ.ckFnGv1NT-Ui2S90DNr50YoHSXc1ZLBNnEErnGMWL-E'
secret ='123456AB' 
jwt.decode(token,secret,algorithms='HS256')

Traceback (most recent call last): File "", line 1, in File "/Applications/anaconda/envs/modulename/lib/python3.5/site-packages/jwt/api_jwt.py", line 64, in decode options, **kwargs) File "/Applications/anaconda/envs/modulename/lib/python3.5/site-packages/jwt/api_jws.py", line 116, in decode key, algorithms) File "/Applications/anaconda/envs/modulename/lib/python3.5/site-packages/jwt/api_jws.py", line 186, in _verify_signature raise DecodeError('Signature verification failed') jwt.exceptions.DecodeError: Signature verification failed

If i use the same token in jwt.io, with base64 encrypted option checked, it seems to work.

Solution

This is because when Java created the token it thought the plain text you used as a secret was base64 encoded. I am assuming Java was expecting the string secret to be base64 encoded version of some binary. Try base64 decoding the secret before decoding jwt.

import base64
jwt.decode(token,base64.b64decode(secret))

#The token in your question was expired so I ended up passing verify expiration = False
jwt.decode(token,base64.b64decode(secret), options={ 'verify_exp': False})

{u'iat': 1494858980, u'exp': 1494864980, u'sub': u'100', u'roles': u'BUSINESSUSER', u'mode': u'storeapp'}