c#中逻辑异或问题

Question

以下是小弟模仿书里写的代码：
public partial class Form1 : Form
{
char ch1 = 'O', ch2 = 'K';
int key = 0x1f;
public Form1()
{
InitializeComponent(); // 加载控件代码
}

private void btnMingWen_Click(object sender, EventArgs e)
{
txtMingWen.Text = "明文:" + ch1 + ch2;
}

private void btnMiwen_Click(object sender, EventArgs e)
{
ch1 = (char)(ch1 ^ key);
ch2 = (char)(ch2 ^ key);
txtMiWen.Text = "密文:" + ch1 + ch2; //这里不懂...
}

private void btnJieMi_Click(object sender, EventArgs e)
{
ch1 = (char)(ch1 ^ key);
ch2 = (char)(ch2 ^ key);
txtJieMi.Text = "解码:" + ch1 + ch2;
}
}
我对着书里的练习做，但
ch1 = (char)(ch1 ^ key);
ch2 = (char)(ch2 ^ key);
txtMiWen.Text = "密文:" + ch1 + ch2;
前面两句的ch1^key的结果是P，ch2^key的结果是T？小弟刚接触编程，不是很懂，有望各位高手指教，谢谢！
是幂运算的话，结果为什么是O^0x1f=P K^0x1f=T?

Answer 1

ch1中的值的二进制码与key的二进制码按位取异或，然后得出的二进制码在转换成字符型输出

Answer 2

^是幂运算，就是ch1的key次幂