Reply To: Competitor Ciphers & Challenges

Upsidedown – Bombe

To start this thread off, I wanted to re-highlight a challenge made by upsidedown last year, designed around the Turing–Welchman Bombe.
All credit goes to upsidedown for this challenge, thank you!
This challenge was originally posted in Harry’s Christmas Miscellany. However, very few people have solved it, and it appears no solutions were posted on the forums last year (mine didn’t get through the moderation pipeline before the forums closed). I think that such a well put together challenge deserves more attention from competitors.

Alumni, this will be fun for you too.

https://www.cipherchallenge.org/wp-content/uploads/2025/12/CC2025-the-bombe.pdf
https://www.cipherchallenge.org/wp-content/uploads/2025/12/CC2025-the-bombe.pdf