Skip to content

Instantly share code, notes, and snippets.

@splitbrain

splitbrain/azure-ad-b2c-jwt-rsa.php

Created April 15, 2019 12:57
Download ZIP

Revisions

  1. splitbrain created this gist Apr 15, 2019.
    35 changes: 35 additions & 0 deletions azure-ad-b2c-jwt-rsa.php
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,35 @@
    <?php

    // composer require phpseclib/phpseclib
    require_once('vendor/autoload.php');


    $tenant = 'cosmocode';
    $policy = 'b2c_1_signupandsignin';

    $json = file_get_contents("https://$tenant.b2clogin.com/$tenant.onmicrosoft.com/$policy/discovery/v2.0/keys");
    $data = json_decode($json, true);
    $keydata = $data['keys'][0]; // FIXME keyid should be compared with kid from token

    $rsa = new phpseclib\Crypt\RSA();
    $rsa->loadKey(
    array(
    'e' => new phpseclib\Math\BigInteger(urlsafeB64Decode($keydata['e']), 256),
    'n' => new phpseclib\Math\BigInteger(urlsafeB64Decode($keydata['n']), 256),
    )
    );

    var_dump($rsa->getPublicKey());



    // @FIXME use the function from a JWT library
    function urlsafeB64Decode($input)
    {
    $remainder = strlen($input) % 4;
    if ($remainder) {
    $padlen = 4 - $remainder;
    $input .= str_repeat('=', $padlen);
    }
    return base64_decode(strtr($input, '-_', '+/'));
    }