Level 2 - Decode ROT13 string to get password (Cryptography)

Description

A SSH password is encrypted using ROT13. The word boundaries remain untouched. Decode it to get the password.

Theory

ROT13 is a simple letter substitution cipher that replaces a letter with the 13th letter after it in the Latin alphabet.

ROT13 is a special case of the Caesar cipher.

Tech used

• cd
• tr

Solutions

Run ssh krypton1@krypton.labs.overthewire.org -p 2231. Password is KRYPTONISGREAT

• Use tr tool to translate all letters to the new window
  • Run cd /krypton/krypton1
  • Run cat krypton2 | tr 'A-Za-z' 'N-ZA-Mn-za-m'

Notes

• The translated window requires 4 ranges due to Z+13 rotating back to the start of the alphabet