To implement the Secure Multi-Party Computation (SMPC) in ns3, we need to emulate the network where multiple parties can cooperatively calculate a function over their inputs while keeping those inputs private. We need to emulate the SMPC protocol at a high level but ns3 does not have a built-in support for cryptographic protocols. This sample will guide you through setting up a basic simulation where multiple nodes exchange encrypted messages and jointly compute a result.
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”
Step 3: Create the Simulation Script
- Setup Nodes and Network:
using namespace ns3;
NS_LOG_COMPONENT_DEFINE (“SecureMultiPartyComputationExample”);
class SmpcApplication : public Application
{
public:
SmpcApplication ();
virtual ~SmpcApplication ();
void Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate);
private:
virtual void StartApplication (void);
virtual void StopApplication (void);
void ScheduleTx (void);
void SendPacket (void);
void HandleRead (Ptr<Socket> socket);
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;
};
SmpcApplication::SmpcApplication ()
: m_socket (0),
m_peer (),
m_packetSize (0),
m_nPackets (0),
m_dataRate (0),
m_sendEvent (),
m_running (false),
m_packetsSent (0)
{
}
SmpcApplication::~SmpcApplication ()
{
m_socket = 0;
}
void
SmpcApplication::Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate)
{
m_socket = socket;
m_peer = address;
m_packetSize = packetSize;
m_nPackets = nPackets;
m_dataRate = dataRate;
}
void
SmpcApplication::StartApplication (void)
{
m_running = true;
m_packetsSent = 0;
m_socket->Bind ();
m_socket->Connect (m_peer);
m_socket->SetRecvCallback (MakeCallback (&SmpcApplication::HandleRead, this));
SendPacket ();
}
void
SmpcApplication::StopApplication (void)
{
m_running = false;
if (m_sendEvent.IsRunning ())
{
Simulator::Cancel (m_sendEvent);
}
if (m_socket)
{
m_socket->Close ();
}
}
void
SmpcApplication::SendPacket (void)
{
Ptr<Packet> packet = Create<Packet> (m_packetSize);
m_socket->Send (packet);
if (++m_packetsSent < m_nPackets)
{
ScheduleTx ();
}
}
void
SmpcApplication::ScheduleTx (void)
{
if (m_running)
{
Time tNext (Seconds (m_packetSize * 8 / static_cast<double> (m_dataRate.GetBitRate ())));
m_sendEvent = Simulator::Schedule (tNext, &SmpcApplication::SendPacket, this);
}
}
void
SmpcApplication::HandleRead (Ptr<Socket> socket)
{
Ptr<Packet> packet;
Address from;
while ((packet = socket->RecvFrom (from)))
{
NS_LOG_UNCOND (“Received ” << packet->GetSize () << ” bytes from ” << InetSocketAddress::ConvertFrom (from).GetIpv4 ());
// Process the received packet (e.g., decrypt and perform computation)
}
}
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 = 9; // Discard port (RFC 863)
// Server application on node 3
Address serverAddress (InetSocketAddress (Ipv4Address::GetAny (), port));
PacketSinkHelper packetSinkHelper (“ns3::UdpSocketFactory”, serverAddress);
ApplicationContainer sinkApps = packetSinkHelper.Install (nodes.Get (3));
sinkApps.Start (Seconds (1.0));
sinkApps.Stop (Seconds (20.0));
// Client applications on nodes 0, 1, and 2
for (uint32_t i = 0; i < 3; ++i)
{
Ptr<Socket> source = Socket::CreateSocket (nodes.Get (i), UdpSocketFactory::GetTypeId ());
Address remoteAddress (InetSocketAddress (interfaces.GetAddress (3), port));
Ptr<SmpcApplication> app = CreateObject<SmpcApplication> ();
app->Setup (source, remoteAddress, 1024, 1000, DataRate (“1Mbps”));
nodes.Get (i)->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 SecureMultiPartyComputationExample
Explanation
- Node Creation: Create nodes representing different parties involved in the SMPC.
- 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: Use SmpcApplication to simulate the exchange of encrypted messages and joint computation.
- Message Handling: The HandleRead method processes received packets, which can include decrypting the message and performing part of the computation.
Advanced SMPC Techniques
- Encryption and Decryption:
Implement actual encryption and decryption algorithms to simulate secure message exchange. ns3 itself does not support encryption, but you can integrate external cryptographic libraries if needed.
// Example pseudo-code for encryption
void EncryptAndSend (Ptr<Packet> packet)
{
// Encrypt packet data
// Send encrypted packet
}
- Joint Computation:
Implement the logic for the joint computation in the HandleRead method.
void SmpcApplication::HandleRead (Ptr<Socket> socket)
{
Ptr<Packet> packet;
Address from;
while ((packet = socket->RecvFrom (from)))
{
NS_LOG_UNCOND (“Received ” << packet->GetSize () << ” bytes from ” << InetSocketAddress::ConvertFrom (from).GetIpv4 ());
// Decrypt packet data
// Perform part of the computation
// Send partial result to other parties
}
}
- Fault Tolerance:
Implement fault tolerance mechanisms to handle node failures or packet losses.
// Example pseudo-code for fault tolerance
void HandleFailure ()
{
// Detect failure
// Re-route messages or reassign tasks
}
- Performance Monitoring:
Use ns3’s FlowMonitor or other tools to monitor the performance of the SMPC protocol.
FlowMonitorHelper flowmon;
Ptr<FlowMonitor> monitor = flowmon.InstallAll ();
Simulator::Stop (Seconds (20.0));
Simulator::Run ();
monitor->SerializeToXmlFile (“smpc-flowmon-results.xml”, true, true);
Finally, we explore the basic implementation procedures how to simulate the Secure Multi-Party Computation in ns3 tool and we also provide related information about Secure Multi-Party Computation.
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