re | BUUCTF findit

最新推荐文章于 2025-02-26 11:27:30 发布

Mintind

最新推荐文章于 2025-02-26 11:27:30 发布

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分类专栏： CTF 文章标签： CTF re

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题目：BUUCTF findit

是个apk文件，用jadx打开，找到MainActivity
在这里插入图片描述大概逻辑是，由给定的a数组得到x数组，用户输入和x相等时会输出flag——由给定的b数组得到的y数组，不相等则输出提示
总之东西都给了，稍微转换一下运行就能得到flag

char a[] = {'T', 'h', 'i', 's', 'I', 's', 'T', 'h', 'e', 'F', 'l', 'a', 'g', 'H', 'o', 'm', 'e'};
char b[] = {'p', 'v', 'k', 'q', '{', 'm', '1', '6', '4', '6', '7', '5', '2', '6', '2', '0', '3', 
'3', 'l', '4', 'm', '4', '9', 'l', 'n', 'p', '7', 'p', '9', 'm', 'n', 'k', '2', '8', 'k', 
'7', '5', '}'};
char x[17];
char y[38];
for (int i = 0; i < 17; i++) {
    if ((a[i] < 'I' && a[i] >= 'A') || (a[i] < 'i' && a[i] >= 'a')) {
        x[i] = (char) (a[i] + 18);
    } else if ((a[i] >= 'A' && a[i] <= 'Z') || (a[i] >= 'a' && a[i] <= 'z')) {
        x[i] = (char) (a[i] - '\b');
    } else {
        x[i] = a[i];
    }
}

//string m = x, input;
//if (m == input) {
    for (int i2 = 0; i2 < 38; i2++) {
        if ((b[i2] >= 'A' && b[i2] <= 'Z') || (b[i2] >= 'a' && b[i2] <= 'z')) 
		{
            y[i2] = (char) ((int)b[i2] + 16);
            if ((y[i2] > 'Z' && y[i2] < 'a') || y[i2] >= 'z') 
			{
                y[i2] = (char) (y[i2] - 26);
            }
        } 
		else 
		{
            y[i2] = b[i2];
        }
    }
    cout << endl;

//        String n = String.valueOf(y);
//        text.setText(n);
    cout << x << endl;
    cout << y << endl;
//}