Cyber Apocalypse CTF 2021 Part 2

In the second part of our wrap-up after the success of Cyber Apocalypse CTF 2021, we break down the four hardest challenges we included. RuneScape was a challenge based on the Imai-Matsumoto cryptosystem. Tetris 3D built on the classic cipher given in Tetris. Hyper Metroid required computing the order of the Jacobian of a special class of hyperelliptic curves and SpongeBob SquarePants was a backdoored sponge hash collision. We loved making these challenges and hope you enjoy the write-up.