I need to bake it!
We are given problem.py, which is a interesting cipher/hash algorithm.
The hash basically takes our input, multiplies it with basically a random number for our purposes, and XORs every element with a fixed value, and adds the value a whole bunch of times to the last number(not sure if this was a typo)
Since XOR is reversible, we simply reverse the XOR, and take the GCD of multiple attempts
Strangely the flag is different before and after the ctf, not exactly sure why
Flag:
hsctf{th1s_1s_0ne_v3ry_l0ng_fl@g_b3ca8s3_t5x_l0v3z_vveR9_LOn9_flaGs7!} (during ctf) / hsctf{thiii111iiiss_isssss_yo0ur_b1rthd4y_s0ng_it_isnt_very_long_6621} (after ctf)