How to implement birthday attack in OMNeT++
To implement the birthday attack in OMNeT++ needs to understanding of the attack’s framework. It is a kind of cryptographic attack that takes benefits of the birthday paradox to discover collisions in hash functions. Now the aim is to discover inputs that produce the similar hash value.
Though OMNeT++ is primarily a network simulator, we can mimic a scenario where the birthday attack might be relevant, like in the context of a hash-based authentication or integrity check system. The following is the procedure to execute the simplified birthday attack scenario in OMNeT++:
Step-by-Step Implementations:
- Set up OMNeT++ and INET Framework
- Make sure that OMNeT++ and the INET framework are installed and correctly configured. While OMNeT++ doesn’t directly offer cryptographic libraries, we can mimic the behaviour of hash functions and collisions using custom modules.
- Define the Network Topology
- Make a network topology in a .ned file that contains nodes representing clients, potentially an attacker, and server. The scenario will include transmitting data with hash-based integrity checks.
Example:
network BirthdayAttackNetwork
{
submodules:
client: StandardHost;
server: StandardHost;
attacker: StandardHost;
router: Router;
connections:
client.ethg++ <–> Eth10G <–> router.ethg++;
attacker.ethg++ <–> Eth10G <–> router.ethg++;
router.ethg++ <–> Eth10G <–> server.ethg++;
}
- The attacker node will try to discover collisions in hash values used among the client and server.
- Create a Custom Hash Function and Collision Module
- To simulate the birthday attack, generate a custom module that simulates a hash function and permits for the detection of collisions.
Example C++ code for a custom hash and collision detection module:
#include <omnetpp.h>
#include <unordered_map>
#include <string>
#include <random>
using namespace omnetpp;
class BirthdayAttack : public cSimpleModule
{
private:
std::unordered_map<std::string, std::string> hashTable;
std::hash<std::string> str_hash;
std::mt19937 rng;
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
std::string generateRandomInput();
std::string computeHash(const std::string &input);
void attemptCollision();
};
void BirthdayAttack::initialize()
{
rng.seed(std::random_device()());
// Schedule the first collision attempt
scheduleAt(simTime() + par(“startTime”), new cMessage(“attemptCollision”));
}
void BirthdayAttack::handleMessage(cMessage *msg)
{
if (msg->isSelfMessage()) {
attemptCollision();
scheduleAt(simTime() + par(“interval”), msg); // Continue attempting collisions
} else {
delete msg;
}
}
std::string BirthdayAttack::generateRandomInput()
{
std::uniform_int_distribution<int> dist(0, 15);
std::string input;
for (int i = 0; i < 8; ++i) {
input += “0123456789ABCDEF”[dist(rng)];
}
return input;
}
std::string BirthdayAttack::computeHash(const std::string &input)
{
size_t hashValue = str_hash(input);
return std::to_string(hashValue % 256); // Simplified hash function
}
void BirthdayAttack::attemptCollision()
{
std::string input = generateRandomInput();
std::string hashValue = computeHash(input);
auto it = hashTable.find(hashValue);
if (it != hashTable.end()) {
EV << “Collision detected: ” << it->second << ” and ” << input << ” both have hash ” << hashValue << “\n”;
} else {
hashTable[hashValue] = input;
}
}
Define_Module(BirthdayAttack);
- In this module, computeHash mimics a simplified hash function, and attemptCollision makes random inputs to discover two different inputs that produce the similar hash value.
- Configure the Attacker Node
- In the .ini file, configure the attacker node with the help of birthday attack module.
Example configuration in omnetpp.ini:
*.attacker.numApps = 1
*.attacker.app[0].typename = “BirthdayAttack”
*.attacker.app[0].startTime = 1s
*.attacker.app[0].interval = 0.1s # Interval between collision attempts
- startTime defines when the collision attempts start.
- interval controls how often the attacker generates new inputs to attempt finding collisions.
- Simulate Communication between Client and Server
- Configure the client and server nodes to mimic the transmission of messages where each message embraces a hash value. The attacker node will try to discover hash collisions to exploit this.
Example:
*.client.numApps = 1
*.client.app[0].typename = “TcpBasicClientApp”
*.client.app[0].connectAddress = “server”
*.client.app[0].connectPort = 80
*.client.app[0].requestData = “DATA with HASH\r\n”
*.server.numApps = 1
*.server.app[0].typename = “TcpServerApp”
- The client sends a message including a data payload and a hash to the server, which the attacker tries to replicate or collide.
- Run the Simulation
- Compile and run the OMNeT++ simulation. The attacker node will start trying to find hash collisions based on the hash function described in the custom module.
- Analyze the Results
- To view the attempts made by the attacker to find hash collisions by using OMNeT++’s built-in tools. Observe when the attacker successfully finds two inputs with the similar hash.
- Enhancements and Variations
- Complex Hash Functions: Swap the simple hash function with more complex algorithms or real hash functions to mimic extra realistic scenarios.
- Network Defence Mechanisms: Implement and test defence mechanisms that avoid or detect hash collisions, like using stronger hash functions or putting salt to the inputs.
- Distributed Attacks: Mimic numerous attacker nodes working mutually to find collisions faster, simulating distributed attacks.
Example Files
We can make the following files as part of the simulation:
- BirthdayAttackNetwork.ned: States the network topology.
- omnetpp.ini: Encompasses configuration settings for the birthday attack.
- BirthdayAttack.cc: Custom C++ code for the birthday attack module.
Finally, we see to create custom hack function and collision module, communication between server and client, to analyse the outcomes and some example file to execute Birthday Attack using INET framework in OMNeT++. We will offer more details about this topic as per your needs. Obtain our assistance for the implementation and simulation of all aspects related to executing a birthday attack within the OMNeT++ program.