private static byte[] DecryptMessage(ZWaveNode node, byte[] message, int start)
{
SecurityData nodeSecurityData = GetSecurityData(node);
Utility.DebugLog(DebugMessageType.Information, "In DecryptMessage - SecurityHandler");
if (nodeSecurityData.ControllerNonceTimer.ElapsedMilliseconds > 10000)
{
Utility.DebugLog(DebugMessageType.Information, "Received the nonce too late'" + nodeSecurityData.ControllerNonceTimer.ElapsedMilliseconds + "' > 10000");
return(null);
}
// Utility.DebugLog(DebugMessageType.Information, "Message to be decrypted: " + BitConverter.ToString(message));
// Get IV from inbound packet
byte[] iv = new byte[16];
Array.Copy(message, start + 1, iv, 0, 8);
byte[] currentNonce = nodeSecurityData.GetControllerCurrentNonce(true);
if (currentNonce == null)
{
Utility.DebugLog(DebugMessageType.Information, "currentNonce null");
return(null);
}
Utility.DebugLog(DebugMessageType.Information, "currentNonce NOT null");
Array.Copy(currentNonce, 0, iv, 8, 8);
int _length = message.Length;
int encryptedpackagesize = _length - 11 - 8; //19 + 11 + 8
byte[] encryptedpacket = new byte[encryptedpackagesize];
Array.Copy(message, 8 + start + 1, encryptedpacket, 0, encryptedpackagesize);
byte[] decryptedpacket = AesWork.EncryptOfbMessage(nodeSecurityData.EncryptionKey, iv, encryptedpacket);
Utility.DebugLog(DebugMessageType.Information, "Message " + BitConverter.ToString(message));
Utility.DebugLog(DebugMessageType.Information, "IV " + BitConverter.ToString(iv));
//Utility.DebugLog(DebugMessageType.Information, "Encrypted Packet " + BitConverter.ToString(encryptedpacket));
Utility.DebugLog(DebugMessageType.Information, "Decrypted Packet " + BitConverter.ToString(decryptedpacket));
byte[] mac = GenerateAuthentication(nodeSecurityData.AuthorizationKey, message, start, _length, node.Id, 0x01, iv);
byte[] e_mac = new byte[8];
Array.Copy(message, start + 8 + encryptedpackagesize + 2, e_mac, 0, 8);
if (!Enumerable.SequenceEqual(mac, e_mac))
{
Utility.DebugLog(DebugMessageType.Information, "Computed mac " + BitConverter.ToString(mac) + " does not match the provider mac " + BitConverter.ToString(e_mac) + ". Dropping.");
if (nodeSecurityData.SecurePayload.Count > 1)
{
RequestNonce(node);
}
return(null);
}
/*
* if (decryptedpacket[1] == (byte)CommandClass.Security && 1 == 0)
* {
* byte[] msg = new byte[decryptedpacket.Length - 1];
* Array.Copy(decryptedpacket, 1, msg, 0, msg.Length);
*
* Utility.DebugLog(DebugMessageType.Information, "Processing Internally: " + BitConverter.ToString(msg));
*
* }
* else
* {
*/
byte[] msg = new byte[decryptedpacket.Length - 2 + 8];
Array.Clear(msg, 0, 7);
Array.Copy(decryptedpacket, 1, msg, 7, msg.Length - 7);
msg[6] = (byte)(msg.Length - 7);
Utility.DebugLog(DebugMessageType.Information, "Forwarding: " + BitConverter.ToString(msg));
/* send to the Command Class for Proecssing */
Utility.DebugLog(DebugMessageType.Information, "Received External Command Class: " + BitConverter.ToString(new byte[] { decryptedpacket[1] }));
// node.MessageRequestHandler(node.pController, msg);
Utility.DebugLog(DebugMessageType.Information, "In DecryptMessage - Finished");
return(msg);
}
private static byte[] GenerateAuthentication(byte[] authorizationKey, byte[] data, int start, int length, byte sendingNode, byte receivingNode, byte[] iv)
{
// data should stat at 4
byte[] buffer = new byte[256];
byte[] tmpauth = new byte[16];
int ib = 0;
buffer[ib] = data[start + 0];
ib++;
buffer[ib] = sendingNode;
ib++;
buffer[ib] = receivingNode;
ib++;
buffer[ib] = (byte)(length - 19);
Array.Copy(data, start + 9, buffer, 4, buffer[3]);
byte[] buff = new byte[length - 19 + 4];
Array.Copy(buffer, buff, length - 19 + 4);
// Utility.DebugLog(DebugMessageType.Information, "Raw Auth (minus IV)" + BitConverter.ToString(buff));
tmpauth = AesWork.EncryptEcbMessage(authorizationKey, iv);
byte[] encpck = new byte[16];
Array.Clear(encpck, 0, 16);
int block = 0;
for (int i = 0; i < buff.Length; i++)
{
encpck[block] = buff[i];
block++;
if (block == 16)
{
for (int j = 0; j < 16; j++)
{
tmpauth[j] = (byte)(encpck[j] ^ tmpauth[j]);
encpck[j] = 0;
}
block = 0;
tmpauth = AesWork.EncryptEcbMessage(authorizationKey, tmpauth);
}
}
/* any left over data that isn't a full block size*/
if (block > 0)
{
for (int i = 0; i < 16; i++)
{
tmpauth[i] = (byte)(encpck[i] ^ tmpauth[i]);
}
tmpauth = AesWork.EncryptEcbMessage(authorizationKey, tmpauth);
}
byte[] auth = new byte[8];
Array.Copy(tmpauth, auth, 8);
// Utility.DebugLog(DebugMessageType.Information, "Computed Auth " + BitConverter.ToString(auth));
return(auth);
}
// IN the mesage to be Encrypted
// OUT - true - message processed and sent - proceed to next one
// - false - we need to wait for the nonce report to come
private static bool EncryptMessage(ZWaveNode node, byte[] message)
{
SecurityData nodeSecurityData = GetSecurityData(node);
Utility.DebugLog(DebugMessageType.Information, "In EncryptMessage - secure_payload [" + nodeSecurityData.SecurePayload.Count + "] - " + nodeSecurityData.DeviceNonceTimer.ElapsedMilliseconds);
// if we get true we need to wait for the new Nonce
// if we get false we need to proceed
// if (sendRequestNonce())
// return false;
if (nodeSecurityData.DeviceNonceTimer.ElapsedMilliseconds > 10000)
{
return(false);
}
SecutiryPayload payload = null;
lock (nodeSecurityData.SecurePayload)
{
if (nodeSecurityData.SecurePayload.Count > 0)
{
payload = nodeSecurityData.SecurePayload.First();
nodeSecurityData.SecurePayload.Remove(payload);
}
}
if (payload != null)
{
int len = payload.length + 20;
byte[] t_message = new byte[len];
int i = 0;
t_message[i] = (byte)CommandClass.Security;
i++;
t_message[i] = (byte)SecurityCommand.MessageEncap;
byte[] initializationVector = new byte[16];
for (int a = 0; a < 8; a++)
{
initializationVector[a] = (byte)0xAA;
i++;
t_message[i] = initializationVector[a];
}
Array.Copy(nodeSecurityData.DeviceCurrentNonce, 0, initializationVector, 8, 8);
int sequence = 0;
if (payload.part == 1)
{
++nodeSecurityData.SequenceCounter;
sequence = nodeSecurityData.SequenceCounter & (byte)0x0f;
sequence |= (byte)0x10;
}
else if (payload.part == 2)
{
++nodeSecurityData.SequenceCounter;
sequence = nodeSecurityData.SequenceCounter & (byte)0x0f;
sequence |= (byte)0x30;
}
byte[] plaintextmsg = new byte[payload.length + 1];
plaintextmsg[0] = (byte)sequence;
for (int a = 0; a < payload.length; a++)
{
plaintextmsg[a + 1] = payload.message[a];
}
byte[] encryptedPayload = new byte[30];
encryptedPayload = AesWork.EncryptOfbMessage(nodeSecurityData.EncryptionKey, initializationVector, plaintextmsg);
Utility.DebugLog(DebugMessageType.Information, "authKey " + BitConverter.ToString(nodeSecurityData.AuthorizationKey));
Utility.DebugLog(DebugMessageType.Information, "EncryptKey " + BitConverter.ToString(nodeSecurityData.EncryptionKey));
Utility.DebugLog(DebugMessageType.Information, "Input Packet: " + BitConverter.ToString(plaintextmsg));
Utility.DebugLog(DebugMessageType.Information, "IV " + BitConverter.ToString(initializationVector));
Utility.DebugLog(DebugMessageType.Information, "encryptedPayload " + BitConverter.ToString(encryptedPayload));
for (int a = 0; a < payload.length + 1; ++a)
{
i++;
t_message[i] = encryptedPayload[a];
}
i++;
t_message[i] = nodeSecurityData.DeviceCurrentNonce[0];
//GenerateAuthentication
int start = 1;
byte[] mac = GenerateAuthentication(nodeSecurityData.AuthorizationKey, t_message, start, t_message.Length + 2 - start - 1, 0x01, node.Id, initializationVector);
for (int a = 0; a < 8; ++a)
{
i++;
t_message[i] = mac[a];
}
node.SendDataRequest(t_message);
Utility.DebugLog(DebugMessageType.Information, "In EncryptMessage - message sent");
if ((nodeSecurityData.IsNetworkKeySet == false) && payload.message[0] == (byte)CommandClass.Security && payload.message[1] == (byte)SecurityCommand.NetworkKeySet)
{
nodeSecurityData.IsNetworkKeySet = true;
nodeSecurityData.IsAddingNode = false;
}
return(true);
}
return(true);
}