Virtuous Hmac in PHP

hmac.php

<?php

    function getHmacToken($applicationKey, $requestHttpMethod, $requestUrl)
    {
        $privateKey     = "VIRTUOUS_API_KEY";
        $nonce = uniqid();
        $timestamp  = (string)time();
        $toBeHashed = strtolower($applicationKey . urlencode($requestUrl) . $requestHttpMethod . $nonce . $timestamp);
        $hmac = getHashedUrl($toBeHashed, $privateKey);
        $authorization = "Hmac " . $applicationKey . ":" . $hmac . ":" . $nonce . ":" . $timestamp;
        return $authorization;
    }
    
    function getHashedUrl($toBeHashed, $privateKey)
    {
        $apiKey = base64_decode($privateKey);
        $hmac = hash_hmac(
            "SHA256",
            $toBeHashed, // Hash the combined string
            $apiKey, // Using private dev key to sign it
            true
        );
        $hmac_b64 = base64_encode($hmac);
        return $hmac_b64;
    }