Hello, I’m Hyunsik Jeong a.k.a. RBTree. I mainly write articles related to cryptography, reverse engineering, and other CTF/security-related stuffs here.
2022 ํ๊ณ ๋ฐ 2023๋ ๋ชฉํ
์ฐ์ธํจ์ ๊ณ ๋ฆฌ๋ฅผ ๋์ผ๋ฉฐ ์๋ ํ๊ณ ๊ธ์ ๋ณด๋ ์์ฒญ ํ๋ค์๋ ๊ฑฐ ๊ฐ์ต๋๋ค. ์ฌ์ค ์ด ์ํ๊ฐ ์ฌํด ๋ค์ด์๋ ๋ง์ด ๋์์ง์ง ์์์๋๋ฐ, ํ๋ จ์๋ฅผ ๋ค๋ ์จ ์ ํ๋ก ๋ญ๊ฐ ๊นจ๋ฌ์์ด...
ํ์งํ ํ์ด๋๋(ๅฏๅฃซๆฅใใคใฉใณใ) ํ๊ธฐ
2022๋ 12์ 10์ผ, ํ๋ก๋ผ์ด๋ธ ์ฝ๋ผ๋ณด ๋ฐฉ๋ฌธ์ ์ํด์ ํ์งํ ํ์ด๋๋์ ๋ค๋ ์์ต๋๋ค! ์ด๋ฒ์ ๋ค๋ ์ค๋ฉด์ ์ค๋นํ๋ ๋ฌผํ, ๊ทธ๋ฆฌ๊ณ ์ฝ๋ผ๋ณด ๊ด๋ จํด์ ์ ๋ฆฌํด๋ณด...
Interpolation Attack
I made one crypto challenge each for CODEGATE CTF 2022 quals and finals. In this article, Iโm gonna explain how the interpolation attack works, and show the way to solve my challenge โHidden Command Serviceโ from the finals. Interpolation Attack Once upon a time, there was a dangerous attack technique called โdifferential cryptanalysisโโฆ 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 โinterpolation attackโ, and a variant of KN-Cipher called PURE is broken....
Cube Attack
I made one crypto challenge each for CODEGATE CTF 2022 quals and finals. In this article, Iโm gonna explain how the cube attack works, and show the way to solve my challenge โHappy S-boxโ 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 $g$....
์ ๋ฌธ์ฐ๊ตฌ์์์ ์ํ ํ๋ จ์ ์ค๋น๋ฌผ ๋ฐ ํ
2022๋ 7์ 7์ผ์ ํ๋ จ์์ ์ ์ํด์ 7์ 28์ผ์ ํด์ํ์ต๋๋ค. ๋คํํ๋ ์ข์ ์ฌ๋๋ค๊ณผ ๊ฐ์ ๋ถ๋์์ ์ํํด์ ์ ์ง๋ผ ์ ์์์ต๋๋ค. ์ด ๊ธ์์๋ ๊ฐ์ธ์ ์ผ...