In sum,
1. Factors of RSA modulus can be found efficiently using Fermat's Factorization Method
2. Find [this paper](https://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=5140063BDB10AB1388C9AAB52A8071A1?doi=10.1.1.32.1835&rep=rep1&type=pdf) and understand the cryptosystem inside it.
3. Optimize `v(n)` for fast decryption.

This writeup shares other people's solutions (briefly) as well so do go and check their solutions (in detail) out too!

Details can be found at https://n00bcak.github.io/writeups/2021/03/27/UMass-CTF.html

Original writeup (https://n00bcak.github.io/writeups/2021/03/27/UMass-CTF.html).