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우울함의 고리를 끊으며 작년 회고 글을 보니 엄청 힘들었던 거 같습니다. 사실 이 상태가 올해 들어서도 많이 나아지지 않았었는데, 훈련소를 다녀온 전후로 뭔가 깨달음이...

2022년 12월 10일, 홀로라이브 콜라보 방문을 위해서 후지큐 하이랜드에 다녀왔습니다! 이번에 다녀오면서 준비했던 물품, 그리고 콜라보 관련해서 정리해보...

I made one crypto challenge each for CODEGATE CTF 2022 quals and finals. In this article, I’m gonna explain how the interpolation attack works, and show the way to solve my challenge “Hidden Command Service” from the finals. Interpolation Attack Once upon a time, there was a dangerous attack technique called ‘differential cryptanalysis’… Then, two crypto-magicians made a scheme which is provably safe from the differential cryptanalysis, called KN-Cipher. However, it soon turned out that the structure of S-boxes used in those ciphers are vulnerable to a new attack called ‘interpolation attack’, and a variant of KN-Cipher called PURE is broken....

I made one crypto challenge each for CODEGATE CTF 2022 quals and finals. In this article, I’m gonna explain how the cube attack works, and show the way to solve my challenge “Happy S-box” from the quals. Cube Attack Consider a multivariate equation over $\text{GF}(2)$, $f(x_1, \dots, x_n)$. There will be multiple monomials in $f$, and what we want to do is to pick one monomial $g = x_{i_1}x_{i_2} \cdots x_{i_k}$ and divide $f$ by $g$....

2022년 7월 7일에 훈련소에 입소해서 7월 28일에 퇴소했습니다. 다행히도 좋은 사람들과 같은 분대에서 생활해서 잘 지낼 수 있었습니다. 이 글에서는 개인적으...