Python JWT doesn't validate with google public key

Question

Tried to decode the JWT provided by the google. I have used phone number authentication with google and returned verifyIdToken which is a jwt token. I have tried to verify with the jwt package available in python but it throws error.

When I tried to verify the signature with jwt.io It give a verified signature but it python can't.

Here is the link about the documentation of the google

The public key used is

-----BEGIN CERTIFICATE-----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\nQQ8yX4+6Fq/3xWzUWg4PvAIb4aX8Fwc59uBFc7yeSvg=\n-----END CERTIFICATE-----\n

I tried removing \n and I verified it with jwt.io it worked but it doesn't work in the python the code I wrote is

import jwt

key = "-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----"
token = "XXXXXXXXX"

payload = jwt.decode(token, key.encode(), algorithms=['RS256',])
print(payload)

the error that throwed is

raise ValueError(
ValueError: ('Could not deserialize key data. The data may be in an incorrect format, it may be encrypted with an unsupported algorithm, or it may be an unsupported key type (e.g. EC curves with explicit parameters).', [_OpenSSLErrorWithText(code=75497580, lib=9, reason=108, reason_text=b'error:0480006C:PEM routines::no start line')])

I haven't included the token because it contains data.

Answer 1

I was able to reproduce the following:

import jwt

key = "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAu1SU1LfVLPHCozMxH2Mo4lgOEePzNm0tRgeLezV6ffAt0gunVTLw7onLRnrq0/IzW7yWR7QkrmBL7jTKEn5u+qKhbwKfBstIs+bMY2Zkp18gnTxKLxoS2tFczGkPLPgizskuemMghRniWaoLcyehkd3qqGElvW/VDL5AaWTg0nLVkjRo9z+40RQzuVaE8AkAFmxZzow3x+VJYKdjykkJ0iT9wCS0DRTXu269V264Vf/3jvredZiKRkgwlL9xNAwxXFg0x/XFw005UWVRIkdgcKWTjpBP2dPwVZ4WWC+9aGVd+Gyn1o0CLelf4rEjGoXbAAEgAqeGUxrcIlbjXfbcmwIDAQAB\n-----END PUBLIC KEY-----\n"
token = "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWUsImlhdCI6MTUxNjIzOTAyMn0.NHVaYe26MbtOYhSKkoKYdFVomg4i8ZJd8_-RU8VNbftc4TSMb4bXP3l3YlNWACwyXPGffz5aXHc6lty1Y2t4SWRqGteragsVdZufDn5BlnJl9pdR_kdVFUsra2rWKEofkZeIC4yWytE58sMIihvo9H1ScmmVwBcQP6XETqYd0aSHp1gOa9RdUPDvoXQ5oqygTqVtxaDr6wUFKrKItgBMzWIdNZ6y7O9E0DhEPTbE9rfBo6KTFsHAZnMg4k68CDp2woYIaXbmYTWcvbzIuHO7_37GT79XdIwkm95QJ7hYC9RiwrV7mesbY4PAahERJawntho0my942XheVLmGwLMBkQ"

payload = jwt.decode(token, key.encode(), algorithms=['RS256',])
print(payload)

>>> {'sub': '1234567890', 'name': 'John Doe', 'admin': True, 'iat': 1516239022}

I noticed that in your public key there are some escape characters \n inside your string (this may be causing your problem). You should only remove \n that appear inside the key and include them at the beginning and at the end. Try changing your public key to:

key = "-----BEGIN CERTIFICATE-----\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\n-----END CERTIFICATE-----\n"