vss is an interesting crypto challenge in BalsnCTF, which ended up having 9 solves. I took around 2.5 hours to solve the challenge. This challenge reminds me the yet another PRNG challenge from pbctf 2021, but with a setting which looked harder. I was pretty surprised that LLL worked, too.
lfsr is another crypto challenge in BalsnCTF with 6 solves. In the challenge, the output bits are computed nonlinearly from the LFSR states. Given that I knew almost nothing about LFSR, I just came up with the attack by myself… Well, I am not quite a paper guy and I couldn’t read.