title: buu-re-findit
    tags:

    • CTF
    • RE
    • buu
      abbrlink: 3d2fcb0e
      date: 2021-03-10 20:34:37

    拿到手是一个apk文件，利用Android Killer打开后查看mainActivity里面的相关信息，可以看到一串十六进制数字:0x70,0x76,0x6b,0x71,0x7b,0x6d,0x31,0x36,0x34,0x36,0x37,0x35,0x32,0x36,0x32,0x30,0x33,0x33,0x6c,0x34,0x6d,0x34,0x39,0x6c,0x6e,0x70,0x37,0x70,0x39,0x6d,0x6e,0x6b,0x32 ,0x38,0x6b,0x37,0x35,0x7d。写了一个C语言的小程序来把这串数字转换为字符串

    1. #include<iostream>
    2. #include<vector>
    4. using namespace std;
    6. int main()
    7. {
    8.     vector<int> flag={0x70,0x76,0x6b,0x71,0x7b,0x6d,0x31,0x36,0x34,0x36,0x37,0x35,0x32,0x36,0x32,0x30,0x33,0x33,0x6c,0x34,0x6d,0x34,0x39,0x6c,0x6e,0x70,0x37,0x70,0x39,0x6d,0x6e,0x6b,0x32 ,0x38,0x6b,0x37,0x35,0x7d};
    9.     char s[100];
    10.     for(int i =0; i<flag.size();i++)
    11.     {
    12.         s[i]=char(flag[i]);
    13.     }
    14.     cout<<s<<endl;
    15.     return 0;
    16. }

    得到结果pvkq{m164675262033l4m49lnp7p9mnk28k75}，看符号判断应该是被加密过，使用凯撒解密得到结果flag{c164675262033b4c49bdf7f9cda28a75}