byte[] EncodeMessage(byte[] recipient_pubkey, byte[] msgid, byte[] replyTo, string txt, byte[] prvkey, byte[] pubkey, out byte[] aes_key, out byte[] aes_iv)
{
if (replyTo == null)
replyTo = new byte[16];
var txtbuf = Encoding.UTF8.GetBytes(txt);
var SignMessage = prvkey != null;
byte[] hash = null;
if (SignMessage)
{
using (var rsa = new RSACryptoServiceProvider())
{
RSAParameters rsap;
Shared.LoadKey2(Shared.prvToPem(prvkey), null, out rsap);
rsa.ImportParameters(rsap);
using (var ms = new MemoryStream()) //sign
{
ms.Write(msgid, 0, msgid.Length);
ms.Write(replyTo, 0, replyTo.Length);
ms.WriteShort((short)txtbuf.Length);
ms.Write(txtbuf, 0, txtbuf.Length);
ms.WriteShort((short)pubkey.Length);
ms.Write(pubkey, 0, pubkey.Length);
ms.WriteShort((short)recipient_pubkey.Length);
ms.Write(recipient_pubkey, 0, recipient_pubkey.Length);
ms.Position = 0;
hash = rsa.SignData(ms, SHA512OID);
}
}
}
byte[] c1;
using (var ms1 = new MemoryStream())
using (var ms = new BZip2OutputStream(ms1))
{
ms.Write(txtbuf, 0, txtbuf.Length);
ms.Close();
c1 = ms1.ToArray();
}
var compressText = c1.Length < txtbuf.Length;
byte[] aesmsg;
using (var aes = new RijndaelManaged())
{
using (MemoryStream msEncrypt = new MemoryStream())
{
using (var encryptor = aes.CreateEncryptor())
using (CryptoStream sw2 = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
aes_key = aes.Key;
aes_iv = aes.IV;
sw2.WriteByte((Byte)((compressText ? 1 : 0) | (SignMessage ? 2 : 0)));
sw2.Write(msgid, 0, msgid.Length);
sw2.Write(replyTo, 0, replyTo.Length);
if (compressText)
{
sw2.WriteShort((short)c1.Length);
sw2.Write(c1, 0, c1.Length);
}
else
{
sw2.WriteShort((short)txtbuf.Length);
sw2.Write(txtbuf, 0, txtbuf.Length);
}
if (SignMessage)
{
sw2.WriteShort((short)pubkey.Length);
sw2.Write(pubkey, 0, pubkey.Length);
sw2.WriteShort((short)hash.Length);
sw2.Write(hash, 0, hash.Length);
}
}
msEncrypt.Flush();
aesmsg = msEncrypt.ToArray();
}
}
return aesmsg;
}