$credentialScope, hash('SHA256', $canonicalRequest), ]); $secretDate = hash_hmac...$this->secretKey, true); $secretService = hash_hmac('SHA256', $this->service, $secretDate, true...); $secretSigning = hash_hmac('SHA256', 'tc3_request', $secretService, true); $signature...= hash_hmac('SHA256', $stringToSign, $secretSigning); return implode(', ', [ "{$algorithm