void Send()
{
dateTimeIV = md5.maHoaMd5(DateTime.Now.ToString());
string time = dateTimeIV.Substring(0, 16);
dateTimeIv = Encoding.UTF8.GetBytes(time);
string a = txtFinalKey.Text.Substring(0, 32);
byte[] key = Encoding.ASCII.GetBytes(a);
string s = aes.EncryptString(txtMessage.Text, key, dateTimeIv);
byte[] mahoa = Diff.MaHoaDiffie(nhankey, s);
byte[] dodai = BitConverter.GetBytes(mahoa.Length);
byte[] initvector = Diff.IV;
if (client != null && txtMessage.Text != string.Empty)
{
client.Send(dodai);
client.Send(mahoa);
client.Send(initvector);
}
}
int AddPadding()
{
string Timestamp = new DateTimeOffset(DateTime.UtcNow).ToUniversalTime().ToString("yyyyMMddHHmmssffff");
string MHtimeStamp = md5.maHoaMd5(Timestamp);
int soByteCuaChuoi = UTF8Encoding.UTF8.GetByteCount(textBox1.Text);
int i = 0;
string tmpTime = string.Empty;
if (soByteCuaChuoi % 16 != 0)
{
i = 1;
int length = soByteCuaChuoi;
while (length % 16 != 0)
{
tmpTime = MHtimeStamp.Substring(0, i);
length = length + 1;
i = i + 1;
}
}
textBox1.Text = textBox1.Text + tmpTime;
return(i + 2);
}
void Receive()
{
try
{
c : while (true)
{
byte[] data = new byte[1024];
client.Receive(data);
if (string.Equals(Encoding.UTF8.GetString(data), "guikey", StringComparison.InvariantCultureIgnoreCase))
{
txtServerKey.Clear();
txtFinalKey.Clear();
nhankeydadoi = new byte[140];
client.Receive(nhankeydadoi);
keypublic = Convert.ToBase64String(nhankeydadoi);
txtServerKey.Text = keypublic;
CreatePublicKey();
Diff.LayKhoaBiMat(nhankeydadoi);
khoabimat = Diff.aes.Key;
keysecret = Convert.ToBase64String(khoabimat);
txtFinalKey.Text = keysecret;
nhankey = nhankeydadoi;
guilaipublickey();
}
else if (string.Equals(Encoding.UTF8.GetString(data), "guikeytoclient", StringComparison.InvariantCultureIgnoreCase))
{
txtServerKey.Clear();
txtFinalKey.Clear();
nhankeydadoi = new byte[140];
client.Receive(nhankeydadoi);
keypublic = Convert.ToBase64String(nhankeydadoi);
txtServerKey.Text = keypublic;
Diff.LayKhoaBiMat(nhankeydadoi);
khoabimat = Diff.aes.Key;
keysecret = Convert.ToBase64String(khoabimat);
txtFinalKey.Text = keysecret;
nhankey = nhankeydadoi;
}
else
{
tinnhan = new byte[BitConverter.ToInt32(data, 0)];
client.Receive(tinnhan);
byte[] nhanvector = new byte[16];
client.Receive(nhanvector);
string message = Diff.GiaiMaDiffie(nhankey, tinnhan, nhanvector);
dateTimeIV = md5.maHoaMd5(DateTime.Now.ToString());
string time = dateTimeIV.Substring(0, 16);
dateTimeIv = Encoding.UTF8.GetBytes(time);
string a = txtFinalKey.Text.Substring(0, 32);
byte[] key = Encoding.ASCII.GetBytes(a);
string s = aes.DecryptString(message, key, dateTimeIv);
foreach (char c in s)
{
if (c.ToString() == ";")
{
string[] tokens = s.Trim().Split(';');
compare1 = tokens[1];
compare2 = md5.maHoaMd5(tokens[0]);
if (compare1 != compare2)
{
LstMS.Items.Add("Server: " + tokens[0]);
LstMS.Items.Add("Dữ liệu đã bị thay đổi trong quá trình chuyền:");
LstMS.Items.Add("Chuỗi mã trước:" + compare1);
LstMS.Items.Add("Chuỗi mã sau:" + compare2);
goto c;
}
}
}
LstMS.Items.Add("Server: " + s);
}
}
}catch
{
Close();
}
}