Could not deserialize key data on decoding JWT python

Question

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

Answer 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)