> For the complete documentation index, see [llms.txt](https://gitbook-88.gitbook.io/ctf-writeup/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gitbook-88.gitbook.io/ctf-writeup/ba-chang/gong-fang-shi-jie/simple_js.md).

# simple\_js

```javascript
function dechiffre(pass_enc) {
        var pass = "70,65,85,88,32,80,65,83,83,87,79,82,68,32,72,65,72,65";
        var tab = pass_enc.split(',');
        var tab2 = pass.split(',');
        var i, j, k, l = 0, m, n, o, p = "";
        i = 0;
        j = tab.length;
        k = j + (l) + (n = 0);
        n = tab2.length;
        for (i = (o = 0); i < (k = j = n); i++) {
            o = tab[i - l];
            p += String.fromCharCode((o = tab2[i]));
            if (i == 5) break;
        }
        for (i = (o = 0); i < (k = j = n); i++) {
            o = tab[i - l];
            if (i > 5 && i < k - 1)
                p += String.fromCharCode((o = tab2[i]));
        }
        p += String.fromCharCode(tab2[17]);
        pass = p;
        return pass;
}
String["fromCharCode"](dechiffre("\x35\x35\x2c\x35\x36\x2c\x35\x34\x2c\x37\x39\x2c\x31\x31\x35\x2c\x36\x39\x2c\x31\x31\x34\x2c\x31\x31\x36\x2c\x31\x30\x37\x2c\x34\x39\x2c\x35\x30"));
h = window.prompt('Enter password');
alert(dechiffre(h));
```

修改

```javascript
function dechiffre() {
    var pass = "70,65,85,88,32,80,65,83,83,87,79,82,68,32,72,65,72,65";
    var tab2 = pass.split(',');
    var i, n, p = "";
    n = tab2.length;
    for (i = 0; i < n; i++) {
        p += String.fromCharCode(tab2[i]);
        if (i == 5) break;
    }
    for (i = 0; i < n; i++) {
        if (i > 5 && i < n - 1) p += String.fromCharCode(tab2[i]);
    }
    p += String.fromCharCode(tab2[17]);
    return p;
}
```

发现传入的值实际上是用不到的，无论输入什么样的密码都会报错。该段代码**实质**为输出报错信息。

删除这段函数后，真正的密码在**fromCharCode**中，截取下来转译为数字，在通过Ascii码得到flag。y

```python
array = [55, 56, 54, 79, 115, 69, 114, 116, 107, 49, 50]
string = ""
for i in array:
    char = chr(i)
    string += char
print(string)
```


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