Crypto Challenge 5 - Decoding 5

Prompt

Cyber Command: We have recovered an encrypted message from an operating system, but we have no clue how to decode it. We need your help to decode it.

Answers

What is the plaintext message? (100 pts)
Windows will reboot for an update in 27 minutes

Steps I Took

One of the hardest challenges. Used CyberChef for most attempts.

Started with From Octal as a guess. Then thought about the prompt mentioning an operating system — realized the first word’s length matched “Windows.”

Couldn’t figure out the full recipe myself, so put the encoded string into AI. AI identified the encoding scheme and returned the plaintext. Tried to get it to explain the CyberChef recipe, but it kept giving me operations that don’t exist in CyberChef. Other AIs couldn’t help either.