5: Useless content confusion and line break space TAB method
In the JAVASCRIPT code, we can add a large number of useless strings or numbers, as well as useless code and comment content, etc., so that the real useful code is buried in it, and add a large number of newlines, spaces, and TABs to the useful code, and use normal strings to wrap lines with "\", which will make the code difficult to understand! If I encrypt the form is as follows:
<SCRIPT LANGUAGE="JavaScript">
"xajgxsadffgds";1234567890
625623216;var $=0;alert//@$%%&*()(&(^%^
//cctv function//
(//hhsaasajx xc
/*
asjgdsgu*/
"black\
\
guest\
Line of defense"//ashjgfgf
/*
@#%$^&%667r45fggbhytjty
*/
//window
)
;"#@$#%@#432hu";212351436
</SCRIPT>
At least if I see such a code, I won’t have the heart to analyze it. Where are you?
Six: Self-written decryption function method
This method is similar to one or two, it is just writing a function to decrypt the code. Many VBS viruses use this method to encrypt themselves to prevent feature code scanning! Below is a simple encryption and decryption function I wrote,
The encryption code is as follows (refer to the file "Encryption.htm" for details):
<SCRIPT LANGUAGE="JavaScript">
function compile(code)
{
var c=((0)+);
for(var i=1;i<;i++){
c+=((i)+(i-1));
}
alert(escape(c));
}
compile('alert("Hacker Line");')
</SCRIPT>
Run the encryption result as:
o%CD%D1%D7%E6%9CJ%u9EF3%uFA73%uF1D4%u14F1%u7EE1Kd
The corresponding code for decryption after encryption is as follows:
<SCRIPT LANGUAGE="JavaScript">
function uncompile(code)
{
code=unescape(code);
var c=((0)-);
for(var i=1;i<;i++){
c+=((i)-(i-1));
}
return c;
}
eval(uncompile("o%CD%D1%D7%E6%9CJ%u9EF3%uFA73%uF1D4%u14F1%u7EE1Kd"));
</SCRIPT>
7: Misuse of use
Use the try{}catch(e){} structure to test and decrypt the code. Although this idea is very good (hehe, praise yourself), because it is not very practical, I will only give an example.
<SCRIPT LANGUAGE="JavaScript">
var a='alert("Hacker Line"");';
var c="";
for(var i=0;i<;i++){
c+=((i)^61);}
alert(c);
//The above is the encryption code. Of course, if you really use this method, you will not write the encryption on it.
//Now variable c is the encrypted code
//The following function t() assumes that the initial password is 0, decryption and execution,
//After an error, add 1 to the password, and then decrypt and execute until it runs correctly.
var d=c; //Save the encrypted code
var b=0; //Assuming the initial password is 0
t();
function t(){
try{eval(c);}catch(e){
c="";
for(var i=0;i<;i++){
c+=((i)^b);}
b+=1;
t();
//setTimeout("t()",0);
}
}
</SCRIPT>