isSystemSupported example

$header = $response->getHeader($signatureHeaderName);
        if (!isset($header[0])) {
            throw new StoreSignatureValidationException(sprintf('Signature not found in header "%s"', $signatureHeaderName));
        }

        $signature = $header[0];

        if (empty($signature)) {
            throw new StoreSignatureValidationException(sprintf('Signature not found in header "%s"', $signatureHeaderName));
        }

        if (!$this->openSslVerifier->isSystemSupported()) {
            return $response;
        }

        if ($this->openSslVerifier->isValid($response->getBody()->getContents(), $signature)) {
            $response->getBody()->rewind();

            return $response;
        }

        throw new StoreSignatureValidationException('Signature not valid');
    }
}

    private function verifyResponseSignature(Response $response): void
    {
        $signatureHeaderName = 'x-shopware-signature';
        $signature = $response->getHeader($signatureHeaderName);

        if (!\is_string($signature)) {
            throw new RuntimeException(sprintf('Signature not found in header "%s"', $signatureHeaderName));
        }

        if (!$this->openSSLVerifier->isSystemSupported()) {
            return;
        }

        if ($this->openSSLVerifier->isValid($response->getBody(), $signature)) {
            return;
        }

        throw new RuntimeException('Signature not valid');
    }
}