Python / cryptography: ValueError: Не удалось десериализовать ключевые данные

Question

Я пытаюсь закодировать полезную нагрузку JWT, используя «RS256», но я получаю ошибку ValueError: Could not deserialize key data. из библиотеки криптографии.

import jwt
private_key = b'-----BEGIN PRIVATE KEY-----\nMIGEAgEAMBAGByqGSM49AgEGBS...'
public_key = b'-----BEGIN PUBLIC KEY-----\nMHYwEAYHKoZIzj0CAQYFK4EEAC...'
encoded = jwt.encode({'some': 'payload'}, private_key, algorithm='RS256')

Но я получаю следующую ошибку.

Traceback (most recent call last):
  File "/Users/user1/venv_1/lib/python3.7/site-packages/jwt/algorithms.py", line 205, in prepare_key
    key = load_pem_private_key(key, password=None, backend=default_backend())
  File "/Users/user1/venv_1/lib/python3.7/site-packages/cryptography/hazmat/primitives/serialization.py", line 20, in load_pem_private_key
    return backend.load_pem_private_key(data, password)
  File "/Users/user1/venv_1/lib/python3.7/site-packages/cryptography/hazmat/backends/openssl/backend.py", line 1016, in load_pem_private_key
    password,
  File "/Users/user1/venv_1/lib/python3.7/site-packages/cryptography/hazmat/backends/openssl/backend.py", line 1235, in _load_key
    self._handle_key_loading_error()
  File "/Users/user1/venv_1/lib/python3.7/site-packages/cryptography/hazmat/backends/openssl/backend.py", line 1293, 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 "<stdin>", line 1, in <module>
  File "/Users/user1/venv_1/lib/python3.7/site-packages/jwt/api_jwt.py", line 65, in encode
    json_payload, key, algorithm, headers, json_encoder
  File "/Users/user1/venv_1/lib/python3.7/site-packages/jwt/api_jws.py", line 113, in encode
    key = alg_obj.prepare_key(key)
  File "/Users/user1/venv_1/lib/python3.7/site-packages/jwt/algorithms.py", line 207, in prepare_key
    key = load_pem_public_key(key, backend=default_backend())
  File "/Users/user1/venv_1/lib/python3.7/site-packages/cryptography/hazmat/primitives/serialization.py", line 24, in load_pem_public_key
    return backend.load_pem_public_key(data)
  File "/Users/user1/venv_1/lib/python3.7/site-packages/cryptography/hazmat/backends/openssl/backend.py", line 1042, in load_pem_public_key
    self._handle_key_loading_error()
  File "/Users/user1/venv_1/lib/python3.7/site-packages/cryptography/hazmat/backends/openssl/backend.py", line 1293, in _handle_key_loading_error
    raise ValueError("Could not deserialize key data.")
ValueError: Could not deserialize key data.