De1CTF 2020

Challenge Information category: misc points: 273 Description 赶紧加入游戏吧。 我们在等你 Hurry up and join in the game. We’re waiting for you. http://134.175.230.10/ (cn) http://222.85.25.41/ (cn) http://144.202.79.93/ (us) http://80.240.24.78/ (de) http://45.77.253.164/ (sg) Hint mc_joinin’s flag is: De1CTF{md5(flag)} mc_joinin 的 flag 格式为：De1CTF{md5(flag)} Writeup Author aandryyy fuomag9 Fabbrei rickycraft Solution By looking at the IP given we realized it was a Minecraft challenge. We1c0me t0 De1Ta He4dl3ss M1neCrAft Te2t SeRv3r Minecraft 20.20 is developed by De1ta Team based on 1....

Challenge Information category: crypto points: 235 Description Easy lfsr easy crypto 链接：https://share.weiyun.com/5qZbNLR 密码：n9huwc https://drive.google.com/open?id=1a5GMVZ77CM1rOrayKJcV3UvMwAy-uGsg Writeup Author 0ssigeno meowmeowxw Solution To understand how a general nlsr works, please read this article from ctfwiki. What did we learn from that article? That we must find a strong correlation between the output and one of the input. So we made a little script to retrieve the truth table of (ao * bo) ^ (bo * co) ^ (bo * do) ^ co ^ do The table retrieved is the following:...