******************************************************************************
<?php

$data = /*Response body*/>;

$key ='575bee755dad66b1244bcb709105bf24';

$hashed = hash_hmac('sha256', $data, $key, $raw_output = TRUE);

$base64 = base64_encode($hashed);

$endValue = "sha256=". $base64;

echo $endValue;

******************************************************************************