Validate X Signature CHIP Send

<?php

$content = file_get_contents('php://input');

// chip collect
//if ( openssl_verify( $content,  base64_decode($_SERVER['HTTP_X_SIGNATURE']), 'public_key', 'sha256WithRSAEncryption' ) != 1 ) {

// chip send
if ( openssl_verify( $content,  base64_decode($_SERVER['HTTP_X_SIGNATURE']), 'public_key', 'sha512WithRSAEncryption' ) != 1 ) {
  exit('wrong signature');
}

$content_decoded = json_decode($content, true);

if ($content_decoded['status'] == 'completed') {
  // do something here
}