Level 11

Concept

Substitution cipher (ROT13).

Key Commands

tr (Translate).

Walkthrough

cat data.txt | tr 'A-Za-z' 'N-ZA-Mn-za-m'

To solve this level, I used the tr (translate) command to apply a ROT13 decryption. Since tr doesn’t understand mathematical rotations, I provided two character sets to perform a direct mapping:

• Search set ('A-Za-z'): Represents the complete standard alphabet.
• Replacement set ('N-ZA-Mn-za-m'): Defines the new order. By writing N-ZA-M, I instruct the tool that the range must “wrap around”: it starts at N, goes up to Z, and continues immediately from A to M. This way, each letter in the data.txt file was substituted by its corresponding counterpart 13 positions ahead, revealing the plaintext password.

Key Takeaways

How to map character ranges to shift the alphabet. I understood that ROT13 is reversible using the exact same command.

Pass 12

7x16WNeHIi5YkIhWsfFIqoognUTyj9Q4