Extracted the encryption funciton and then wrote a brute forcer

Solver found here:
https://github.com/balbassam/CTFWriteups/blob/master/2019/TamuCTF/Rev/keygenme/solve.c

Original writeup (https://github.com/balbassam/CTFWriteups/blob/master/2019/TamuCTF/Rev/keygenme/solve.c).