Quantum on z3r0s

Quantum - flagportation

Sun, 10 May 2026 00:00:00 +0000

HTB Write-up: Flagportation Link to heading

Link - https://app.hackthebox.com/challenges/Flagportation

Category: Quantum Difficulty: Very Easy

Summary Link to heading

The server implements a simplified quantum teleportation protocol: it encodes bit pairs (00, 01, 10, 11) into a 3-qubit state, measures the first two qubits and prints the measurement results and the basis (Z or X) used to encode the original bits. Your job is to send instructions (which gates to apply to the third qubit) and choose the measurement basis for the third qubit. From the returned measurement you can reconstruct the original two-bit pair.

Quantum - global hyperlink zone

Sun, 10 May 2026 00:00:00 +0000

HTB Write-up: Global Hyperlink Zone Link to heading

Link - https://app.hackthebox.com/challenges/Global%2520Hyperlink%2520Zone

Category: Quantum Difficulty: Very Easy

Summary Link to heading

The challenge provides a Python script for a server that expects a specific sequence of quantum gates. The goal is to build a quantum circuit that satisfies a set of conditions defined in a validation function within the script. The solution involves creating a specific entangled state across five qubits.

Quantum - noisy vault

Sun, 10 May 2026 00:00:00 +0000

Noisy Vault Writeup Link to heading

Summary Link to heading

The challenge description mentions a 13-qubit system and a 9-bit key, but the actual service uses:

64 data qubits
16 ancilla qubits
a single oracle query
4096 noisy measurement shots

The goal is to recover the hidden 64-bit secret_key and submit it in one unlock attempt.

Root Cause Link to heading

The service prepares the secret as a computational basis state by applying X on each data qubit whose key bit is 1.

Quantum - phase madness

Sun, 10 May 2026 00:00:00 +0000

Title: Phase Madness

Category: Quantum

Difficulty: Easy

Link: https://app.hackthebox.com/challenges/Phase%20Madness

Brief Description Link to heading

The description says "Qubitrix stores data unlike any other. At its core, every secret is locked in a silent quantum spiral, inaccessible to classical developers. The engineers swore it was flawless, yet something in its design hums and breathes. To them, it's madness. To us, clarity."

So, essentially, we are given the server code in Python, server.py.

Quantum - qlotto

Sun, 10 May 2026 00:00:00 +0000

Name - QLotto

Category - Quantum

Difficulty - Easy

Link - https://app.hackthebox.com/challenges/qlotto

Summary Link to heading

The challenge description sets the scene: "They call it QLotto â€” a dazzling new quantum lottery table provided by Qubitrix... If you can predict their draws, you can beat the system." We are provided with a server.py file. The core task is to bypass a restrictive input check on the quantum circuit indices and then manipulate the quantum state to create a predictable correlation between the "house card" and our draws. By using negative indexing and specific quantum gates, we can rig the lottery.

Quantum - untrusted node

Sun, 10 May 2026 00:00:00 +0000

Name - Untrusted Node

Category - Quantum

Difficulty - Medium

Link - https://app.hackthebox.com/challenges/Untrusted%2520Node

Summary Link to heading

The challenge presents a Quantum Key Distribution (QKD) simulation. The "Transmitter" (Alice) sends qubits to a "Receiver" (Bob), but there is a redundancy flaw: for every bit of the key, Alice sends a "chunk" of identical qubits. We act as the compromised "Trusted Node" in the middle. By measuring the first two qubits of each chunk in different bases and letting the rest pass to Bob, we can recover the key without alerting the protocol during the reconciliation phase.