[SWPUCTF 2021 新生赛]re1

1. IDA反编译 发现只是做简单字符替换 写exp
2. exp

#include <iostream>
using namespace std;
string str2 = "{34sy_r3v3rs3}";
void dfs(int now)
{
    if (now == str2.length() - 1)
    {
        cout << "NSSCTF" << str2 << endl;
        return;
    }
    if (str2[now] == 52)
    {
        str2[now] = 97;
        dfs(now + 1);
        str2[now] = 52;
        dfs(now + 1);
    }
    else if (str2[now] == 51)
    {
        str2[now] = 101;
        dfs(now + 1);
        str2[now] = 51;
        dfs(now + 1);
    }
    else
    {
        dfs(now + 1);
    }
}
int main()
{
    freopen("ans.txt", "w", stdout);
    dfs(0);
}

得到flag

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