Classic Cryptography: Holy Riddle

Classical Cryptography: Holy Riddle

This lab challenges you to uncover a hidden flag behind an ancient cipher. As an analyst, you must interpret a riddle, apply classic cryptography techniques, and validate your discovery in a secure environment.

In this lab you will learn:

• How to identify classic ciphers from subtle clues.
• Practical application of text transformations.
• Use of tools like CyberChef or Python scripts.

🌱 How to start this lab

👉 This challenge is validated from the brokendb virtual machine.

1. If you don't have it yet, download the virtual machine from this link:

1https://storage.googleapis.com/cybersecurity-machines/brokendb-lab.ova

1. Import the virtual machine into VirtualBox.
2. Start the VM and log in as user student:4geeks-lab.

📄 Instructions

Your challenge begins with a riddle. Read it carefully: it contains clues about the cipher method used.

Riddle

In a mirror I dwell,
where A becomes Z — you know the spell.
No digits or symbols I rearrange,
just letters flipped in a mirrored exchange.

Ancient as scrolls, simple at first glance,
but crack my code — if you get the chance.

What am I?

Encrypted Flag

14Tvvph{Zgy4hs_15_1mxi3w1yoV_i1tsg???}

Numbers, underscores, and question marks have not been modified.

Your mission:

1. Identify the type of cipher. Hint: it was used in the Bible.
2. Decrypt the message. You can use any method you consider valid: scripts, manual logic or online tools.
3. When you think you have the correct decrypted flag, validate your result inside the virtual machine by running the following command:

1validate-holy-flag

1. Observe the result. If your flag is correct, you will receive a message confirming you have correctly deciphered the Atbash cipher.

This lab is not just about decrypting a text. It's about recognizing ancient patterns, applying reverse logic, and validating results with precision.

💡Tip: The name of the challenge... is also a clue.

Good luck, Analyst!