if len(privateKey) == 0 {
			reader := bufio.NewReader(os.Stdin)
			fmt.Print("Enter Decryption Key: ")

			text, _ := reader.ReadString('\n')
			// convert CRLF to LF
			*keyHex = strings.ReplaceAll(text, "\n", "")
			*keyHex = strings.TrimSpace(*keyHex)
		}
	}

	var inputFileName, outputFileName string

	// Parse parameters
	switch {
	case *stdin: