<?php
$stringToEncode = "GET\n/store/13096/products?page=1&pageSize=10";
$urlEncoded = urlencode($stringToEncode);
$hmac = hash_hmac('sha1', $urlEncoded, "7C23A31E8397FFE44153D1A397147");
$base64 = base64_encode($hmac);

echo $base64;
?>