protected function signRequest($arrayToSign) {
		$stringToSign = Crypto::createSignatureBaseFromArray($arrayToSign);
		$keyFile = $this->config->privateKeyFile;
		$signature = Crypto::signString(
			$stringToSign,
			$keyFile,
			$this->config->privateKeyPassword
		);

		$this->writeToTraceLog("Signing string \"$stringToSign\" using key $keyFile, result: ".$signature);

		return $signature;
	}