To implement the network secure Shell (SSH) in ns3, we need to emulate the network for secure communication.so we need to generate and monitored the SSH traffic using the applications that implement SSH behaviour, like secure communication over TCP with encryption. Since ns3 does not have the built-in SSH support but we provide the detailed procedures on how to implement the SSH using ns3 framework:
Step-by-Step Implementation:
Step 1: Setup ns3 Environment
Make certain ns3 is installed in the system.
Step 2: Include Necessary Modules
Include the necessary ns3 modules in your script:
#include “ns3/core-module.h”
#include “ns3/network-module.h”
#include “ns3/internet-module.h”
#include “ns3/point-to-point-module.h”
#include “ns3/applications-module.h”
#include “ns3/flow-monitor-module.h”
Step 3: Create the Simulation Script
- Setup Nodes and Network:
using namespace ns3;
NS_LOG_COMPONENT_DEFINE (“NetworkSecureShellExample”);
class SshApplication : public Application
{
public:
SshApplication ();
virtual ~SshApplication ();
void Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate, std::string key);
private:
virtual void StartApplication (void);
virtual void StopApplication (void);
void ScheduleTx (void);
void SendPacket (void);
void EncryptPacket (Ptr<Packet> packet);
Ptr<Socket> m_socket;
Address m_peer;
uint32_t m_packetSize;
uint32_t m_nPackets;
DataRate m_dataRate;
EventId m_sendEvent;
bool m_running;
uint32_t m_packetsSent;
std::string m_key;
};
SshApplication::SshApplication ()
: m_socket (0),
m_peer (),
m_packetSize (0),
m_nPackets (0),
m_dataRate (0),
m_sendEvent (),
m_running (false),
m_packetsSent (0)
{
}
SshApplication::~SshApplication ()
{
m_socket = 0;
}
void
SshApplication::Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate, std::string key)
{
m_socket = socket;
m_peer = address;
m_packetSize = packetSize;
m_nPackets = nPackets;
m_dataRate = dataRate;
m_key = key;
}
void
SshApplication::StartApplication (void)
{
m_running = true;
m_packetsSent = 0;
m_socket->Bind ();
m_socket->Connect (m_peer);
SendPacket ();
}
void
SshApplication::StopApplication (void)
{
m_running = false;
if (m_sendEvent.IsRunning ())
{
Simulator::Cancel (m_sendEvent);
}
if (m_socket)
{
m_socket->Close ();
}
}
void
SshApplication::SendPacket (void)
{
Ptr<Packet> packet = Create<Packet> (m_packetSize);
EncryptPacket (packet);
m_socket->Send (packet);
if (++m_packetsSent < m_nPackets)
{
ScheduleTx ();
}
}
void
SshApplication::ScheduleTx (void)
{
if (m_running)
{
Time tNext (Seconds (m_packetSize * 8 / static_cast<double> (m_dataRate.GetBitRate ())));
m_sendEvent = Simulator::Schedule (tNext, &SshApplication::SendPacket, this);
}
}
void
SshApplication::EncryptPacket (Ptr<Packet> packet)
{
// Simple XOR encryption for demonstration purposes
uint8_t *buffer = new uint8_t[packet->GetSize ()];
packet->CopyData (buffer, packet->GetSize ());
for (uint32_t i = 0; i < packet->GetSize (); ++i)
{
buffer[i] ^= m_key[i % m_key.length ()];
}
packet->ReplaceAllPacketData (buffer, packet->GetSize ());
delete[] buffer;
}
int main (int argc, char *argv[])
{
CommandLine cmd;
cmd.Parse (argc, argv);
// Create nodes
NodeContainer nodes;
nodes.Create (4);
// Create point-to-point links
PointToPointHelper pointToPoint;
pointToPoint.SetDeviceAttribute (“DataRate”, StringValue (“10Mbps”));
pointToPoint.SetChannelAttribute (“Delay”, StringValue (“2ms”));
NetDeviceContainer devices;
devices = pointToPoint.Install (NodeContainer (nodes.Get (0), nodes.Get (1)));
devices.Add (pointToPoint.Install (NodeContainer (nodes.Get (1), nodes.Get (2))));
devices.Add (pointToPoint.Install (NodeContainer (nodes.Get (2), nodes.Get (3))));
// Install Internet stack
InternetStackHelper stack;
stack.Install (nodes);
// Assign IP addresses
Ipv4AddressHelper address;
address.SetBase (“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer interfaces = address.Assign (devices);
// Set up applications
uint16_t port = 22; // SSH port
// Server application on node 3
Address serverAddress (InetSocketAddress (Ipv4Address::GetAny (), port));
PacketSinkHelper packetSinkHelper (“ns3::TcpSocketFactory”, serverAddress);
ApplicationContainer sinkApps = packetSinkHelper.Install (nodes.Get (3));
sinkApps.Start (Seconds (1.0));
sinkApps.Stop (Seconds (20.0));
// Client application on node 0
Ptr<Socket> source = Socket::CreateSocket (nodes.Get (0), TcpSocketFactory::GetTypeId ());
Address remoteAddress (InetSocketAddress (interfaces.GetAddress (3), port));
Ptr<SshApplication> app = CreateObject<SshApplication> ();
app->Setup (source, remoteAddress, 1024, 1000, DataRate (“1Mbps”), “mysecretkey”);
nodes.Get (0)->AddApplication (app);
app->SetStartTime (Seconds (2.0));
app->SetStopTime (Seconds (20.0));
Simulator::Stop (Seconds (20.0));
Simulator::Run ();
Simulator::Destroy ();
return 0;
}
Step 4: Run the Simulation
Compile and run your simulation script:
sh
./waf configure
./waf build
./waf –run NetworkSecureShellExample
Explanation
- Node Creation: In the network we make nodes to demonstrating various devices.
- Point-to-Point Links: Configure point-to-point links between nodes with specified data rates and delays.
- Internet Stack: Install the Internet stack on all nodes.
- IP Configuration: Assign IP addresses to the interfaces.
- Applications: Implement a custom application (SshApplication) that simulates SSH traffic by encrypting data using a simple XOR encryption. In a real-world scenario, we need to utilize a more secure encryption algorithm.
- Traffic Generation: Use the custom SshApplication to generate encrypted traffic from a client node to a server node, simulating SSH traffic.
Advanced Secure Shell Techniques
- Advanced Encryption:
Replace the simple XOR encryption with a more advanced encryption algorithm such as AES.
void
SshApplication::EncryptPacket (Ptr<Packet> packet)
{
AesCtrHelper aesCtrHelper;
std::string key = m_key; // Ensure key length is 16 bytes for AES-128
std::string iv = “0123456789abcdef”; // Initialization vector
aesCtrHelper.SetKeyAndIv (key, iv);
uint8_t *buffer = new uint8_t[packet->GetSize ()];
packet->CopyData (buffer, packet->GetSize ());
aesCtrHelper.Encrypt (buffer, buffer, packet->GetSize ());
packet->ReplaceAllPacketData (buffer, packet->GetSize ());
delete[] buffer;
}
- TLS/SSL:
Use Transport Layer Security (TLS) or Secure Sockets Layer (SSL) for secure communication.
// Use ns-3’s built-in TLS/SSL support (not available in standard ns-3, requires additional implementation)
- Authentication:
To guarantee that only authorized nodes can communicate using authentication mechanisms.
bool Authenticate (std::string authToken)
{
std::string validToken = “valid_token”;
return authToken == validToken;
}
- Traffic Analysis Resistance:
Appliance techniques to resist traffic analysis, like adding dummy traffic and constant-rate transmission.
void
SshApplication::SendPacket (void)
{
Ptr<Packet> packet = Create<Packet> (m_packetSize);
EncryptPacket (packet);
m_socket->Send (packet);
// Send dummy packet
Ptr<Packet> dummyPacket = Create<Packet> (m_packetSize);
EncryptPacket (dummyPacket);
m_socket->Send (dummyPacket);
if (++m_packetsSent < m_nPackets)
{
ScheduleTx ();
}
}
Overall, we all understand and get knowledge about the network secure shell to secure the communication over the TCP that were executed in ns3 simulator. We also deliver the more information regarding how it performs and executed in other simulation scenarios.
We are committed to providing you with exceptional project execution ideas for the implementation of Network Secure Shell in ns3tool. Our team will conduct thorough performance analysis and offer support. We specialize in SSH behavior, focusing on secure communication over TCP with encryption.