Challenge Information

  • Name: QLotto

  • Category: Quantum

  • Difficulty: Easy

  • Host: 83.136.252.32:31179

Challenge Description

"They call it QLotto - a dazzling new quantum lottery table provided by Qubitrix that lauders millions at the casino, where quantum draws decide your fate. If you can predict their draws, you can beat the system and clean out their coffers. Rig the jackpot, Operative. Every stolen coin funds their empire - and every coin you steal funds our fight."

Initial Reconnaissance

Analyzing the Provided Files

The challenge provides a single file: server.py. Let's examine its contents:

cat server.py

The server implements a quantum lottery system using Qiskit (IBM's quantum computing framework). Key observations:

  1. Quantum Circuit: Uses 2 qubits (indices 0 and 1)

  2. Initial State: Qubit 0 starts in superposition via circuit.h(0)

  3. User Input: Players provide quantum gate instructions

  4. Measurement: Both qubits are measured 36 times

  5. Number Generation: 6 lottery numbers are extracted from the measurements

Understanding the Code Flow

def generate_circuit(self, instructions: str):
    circuit = QuantumCircuit(2)
    circuit.h(0)  # Qubit 0 in superposition
    
    instructions = instructions.split(";")
    for instr in instructions:
        parts = instr.split(":")
        gate, params = parts
        params = [ int(p) for p in params.split(",") ]
        
        # CRITICAL VALIDATION
        if any(p == 0 for p in params):
            print("[Dealer] Hey, don't tamper with the house card — that's forbidden.")
            return None

Key Restriction: The validation if any(p == 0 for p in params) prevents us from using index 0 in our gate parameters.

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