I liked this challenge, much more creative than the guessing games that many of the other challenges become. The first part is non-trivial, look at classical cryptanalysis and try to adapt one of the methods. I actually found part 2 easier since I’d recently been studying the attack.
If you do a bit of research on the IP they use, you can take out a VPS very physically close to their server - perhaps in the same datacentre ;), which speeds up the attack a lot. I’d also reccomend Sagemath since it makes the mathsy bits a bit easier than raw Python.