protected void Page_Load(object sender, EventArgs e)
{
    RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
    string pwd = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
        + "aaaaaaaaaaaaa"
        + "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
        + "aaaaaaaaaaaaaa";
    int a = Encoding.ASCII.GetBytes(pwd).Length;
    //int length = Encoding.Unicode.GetBytes(pwd).Length;
    byte[] Bytes = rsa.Encrypt(Encoding.ASCII.GetBytes(pwd), false);
}