private void MessageCallBack(IAsyncResult aResult)
{
try
{
int nReceived = sck.EndReceive(aResult);
byte[] receiveData = null;
receiveData = (byte[])aResult.AsyncState;
byte[] ct = new byte[nReceived];
Array.Copy(receiveData, 0, ct, 0, nReceived);
byte[] pubka = new byte[72];
Array.Copy(ct, 0, pubka, 0, 72);
byte[] encryptedmes = new byte[ct.Length - 72];
Array.Copy(ct, 72, encryptedmes, 0, ct.Length - 72);
string receiveMessage = null;
//Decrypt mess
byte[] seck = difhel.DH1(key_pair, pubk);
string key = Convert.ToString(seck);
receiveMessage = aes.Decrypt(encryptedmes, key, 256);
//tách padding
byte[] mesbyte = Encoding.UTF8.GetBytes(receiveMessage);
int length = mesbyte.Length;
byte[] chuoi = new byte[length];
while (mesbyte[length - 1] == 0x00)
{
length--;
}
length--;
Array.Copy(mesbyte, 0, chuoi, 0, length);
string receivemes = System.Text.Encoding.UTF8.GetString(chuoi);
//Adding this message into ListBox
listBox1.Items.Add("Other: " + receivemes);
//Show key DH & encrypt mess
keybox.Text = System.Convert.ToBase64String(pubk);
seckey.Text = System.Convert.ToBase64String(seck);
encryptbox.Text = System.Convert.ToBase64String(encryptedmes);
buffer = new byte[1500];
sck.BeginReceiveFrom(buffer, 0, buffer.Length, SocketFlags.None, ref epRemote, new AsyncCallback(MessageCallBack), buffer);
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}