Vfrdtyky

I am using pyjwt library for decoding the JWT token. I got this error when I am decoding. The code was given in the documantation.

import jwt



encoded_jwt='''eyJ0eXAiOiJKV1QiLCJhbG......'''

secret=b''''-----BEGIN PUBLIC KEY-----

MIIFRjCCBC6gAwIBAgIQCIdSGhpikQCjOIY154XoqzANBgkqhkiG9w0BAQsFADBN

......

-----END PUBLIC KEY-----'''



print(jwt.decode(encoded_jwt, secret , algorithms=['RS256']))

raise ValueError("Could not deserialize key data.") ValueError: Could
not deserialize key data.

Could You please help me in resolving it beacuse when I use this it in the JWT website it's working.

This is the full error log..

Traceback (most recent call last): File
"/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/jwt/algorithms.py",
line 205, in prepare_key
key = load_pem_private_key(key, password=None, backend=default_backend()) File
"/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/cryptography/hazmat/primitives/serialization.py",
line 20, in load_pem_private_key
return backend.load_pem_private_key(data, password) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/cryptography/hazmat/backends/openssl/backend.py",
line 1014, in load_pem_private_key
password, File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/cryptography/hazmat/backends/openssl/backend.py",
line 1233, in _load_key
self._handle_key_loading_error() File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/cryptography/hazmat/backends/openssl/backend.py",
line 1291, in _handle_key_loading_error
raise ValueError("Could not deserialize key data.") ValueError: Could not deserialize key data.

During handling of the above exception, another exception occurred:

Traceback (most recent call last): File
"/home/sathiyakugan/PycharmProjects/JWTsample/sample.py", line 45, in

print(jwt.decode(encoded_jwt, secret , algorithms=['RS256'])) File
"/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/jwt/api_jwt.py",
line 93, in decode
jwt, key=key, algorithms=algorithms, options=options, **kwargs File
"/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/jwt/api_jws.py",
line 157, in decode
key, algorithms) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/jwt/api_jws.py",
line 221, in _verify_signature
key = alg_obj.prepare_key(key) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/jwt/algorithms.py",
line 207, in prepare_key
key = load_pem_public_key(key, backend=default_backend()) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/cryptography/hazmat/primitives/serialization.py",
line 24, in load_pem_public_key
return backend.load_pem_public_key(data) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/cryptography/hazmat/backends/openssl/backend.py",
line 1040, in load_pem_public_key
self._handle_key_loading_error() File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/cryptography/hazmat/backends/openssl/backend.py",
line 1291, in _handle_key_loading_error
raise ValueError("Could not deserialize key data.") ValueError: Could not deserialize key data.

Process finished with exit code 1

There are some issues in the pyjwt library. and you must get the public key from the certificate.

I used openssl x509 -pubkey -noout -in cert.pem > pubkey.pem

then from the public key I could easily decode it using authlib library.

from authlib.specs.rfc7519 import jwt



encoded_jwt='''eyJ0eXAiOiJ....'''

secret=b'''-----BEGIN PUBLIC KEY-----

......

-----END PUBLIC KEY-----'''

claims = jwt.decode(encoded_jwt, secret)

print(claims)

How did you encode your jwt? Use one of the approaches below

Encoding & Decoding Tokens with RS256 (RSA)

encoded = jwt.encode({'some': 'payload'}, private_key, algorithm='RS256')

decoded = jwt.decode(encoded, public_key, algorithms='RS256')

Reading the Claimset without Validation

jwt.decode(encoded, verify=False)

{u'some': u'payload'}

Or use same secret to encode and decode the jwt, one of the approach should work. In my case I used jwt.decode(token, verify=False) because my server has already did the signature validation for me, I only need to get the claimset.