Rating:

Slightly toned down version of last year: 50 encryption oracle challenges. The cipher is a character shift + substitution.

https://advancedpersistentjest.com/2017/11/27/writeups-lucifervm-notes-worth-a-thousand-words-the-never-ending-crypto-tuctf/

Original writeup (https://advancedpersistentjest.com/2017/11/27/writeups-lucifervm-notes-worth-a-thousand-words-the-never-ending-crypto-tuctf/).