I was scared that my RSA would be broken, so I made sure that the numbers were massive.
We are given massive.txt, which are RSA parameters.
Running yafu on n, we see that n is very likely a prime, and passes the fermat test.
The solution is pretty simple, since phi(p)=p-1 for all primes, and we simply calculate ed=1(mod n-1) and m=pow(c,d,n).
Flag:
hsctf{forg0t_t0_mult1ply_prim3s}