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I am using firebase/php-jwt for generating JWT Token using the following PHP Source Code

<?php
include '../vendor/autoload.php';

use Firebase\JWT\JWT;
use Firebase\JWT\Key;

$privateKey = <<<EOD
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
EOD;

$publicKey = <<<EOD
-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC8kGa1pSjbSYZVebtTRBLxBz5H
4i2p/llLCrEeQhta5kaQu/RnvuER4W8oDH3+3iuIYW4VQAzyqFpwuzjkDI+17t5t
0tyazyZ8JXw+KgXTxldMPEL95+qVhgXvwtihXC1c5oGbRlEDvDF6Sa53rcFVsYJ4
ehde/zUxo6UvS7UrBQIDAQAB
-----END PUBLIC KEY-----
EOD;

$payload = [
    'iss' => 'example.org',
    'aud' => 'example.com',
    'iat' => time(),
    'nbf' => time() + 3600,
];

$jwt = JWT::encode($payload, $privateKey, 'RS256');
echo "Encode:\n" . print_r($jwt, true) . "<br/><br/>";

$decoded = JWT::decode($jwt, new Key($publicKey, 'RS256'));

/*
NOTE: This will now be an object instead of an associative array. To get
an associative array, you will need to cast it as such:
 */

$decoded_array = (array) $decoded;
echo "Decode:\n" . print_r($decoded_array, true) . "<br/>";

The code works fine, I am able to decode the Token properly, but when I try to verify the token using the Debugger on https://jwt.io/, it's giving an error saying, it's an invalid token.

Here is the JWT.io link with all the fields.

Note: I have read all the related questions and I am posting this question since they are unable to fix my issue.

Thanks in advance!!!

Screenshot: enter image description here

Akshay Khale
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1 Answers1

1

Your key size is 1024 bit:

# key.pem is
# -----BEGIN RSA PRIVATE KEY-----
# MIICXAIBAAKBgQC8kGa1p...
# ...
openssl rsa -text -noout -in key.pem

RSA Private-Key: (1024 bit, 2 primes)

Now let's check for minimum requirements for RS256:

Required key size: At least 2048 bits

You have to create more secured key

rzlvmp
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  • Do you have the command to generate this key? For the POC, I'm directly using the example from the PHP-JWT Readme.md file. – Akshay Khale Jan 27 '23 at 09:21
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    Do you have the command to generate this key? → how about [this](https://www.google.com/search?client=firefox-b-m&q=generate+rsa+2048+key+rs256&oq=generate+rsa+2048+key+rs256&aqs=heirloom-srp..) one? – rzlvmp Jan 27 '23 at 09:47
  • Hi rzlvmp, You are right, the keys that I generated were incorrect. the following commands worked for me to generate private and public keys `openssl genrsa -out private.pem 2048` and `openssl rsa -in private.pem -pubout -out public.pem` respectively. Best. – Akshay Khale Jan 27 '23 at 12:01