題目資訊

Category: Crypto + Reverse
Point: 150
Description:
This crypto algorithm uses a huge key and it’s implementation is not so trivial to reverse engineer. Isn’t it wonderful?
encrypt.py
flag.enc
pycryptography.so

題目資訊

Category: Crypto + Reverse
Point: 100
Description:
For reasons unknown an amature cryptographer wrote an application to generate “strong encryption keys”. One of these keys was used to encrypt a tar archive with the flag. They used openssl command line util with -aes-128-cbc. Could you please get the flag? It shouldn’t take much time…
flag.zip.enc
keypass

Hints

$ openssl OpenSSL> version OpenSSL 1.1.0e 16 Feb 2017

題目資訊

Category: Web
Point: 100
Description: Send your feedback at bloody-feedback.quals.2017.volgactf.ru

題目資訊

Category: Crypto
Point: 50
Description: There are files A.png and B.png. But where’s the flag?

題目連結：UVa 11559 - Event Planning

題目連結：UVa 579 - Clock Hands

解法1

直接算角度相減，輸出小於等於180度角的部分 (0.030s)

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#include <stdio.h>
#include <math.h>
int main() {
    int h, m;
    float ang1, ang2, ans;
    while (scanf("%d:%d", &h, &m), h || m) {
        ang1 = h * 30 + m * 0.5;
        ang2 = m * 6;
        ans = fabs(ang1 - ang2);
        if (ans > 180)
            ans = 360 - ans;
        printf("%.3f\n", ans);
    }
    return 0;
}

使用 Hexo + Github 建 Blog

先前用過 logdown 來寫文章，但覺得它的 editor 不是很好用，而且還有很多問題（escape問題、光標跑掉等等QQ），所以就放棄了。比對過各種架站方法跟套件，最後選擇用 Hexo + Github 來做，看起來非常自由，架起來也非常快速，而且用 Github hosting 沒煩惱！

碎碎念

一直說要另外架blog寫文章，說了好久都沒有行動，直到現在終於架起來啦！⎝(　ﾟ∀ﾟ)⎠
至於文章走向大概會是放些CTF跟Online Judge題目的解法、技術相關文章，還有一些記事吧。
只不過有沒有那個毅力跟時間去寫就不知道了QQ
請大家多多指教~ ˊˇˋ