How many types of php obfuscation are there?

Obfuscation method:

The two files use 4 obfuscation methods to code Obfuscation

1. Append garbled characters to local variables (Recommended learning: PHP video tutorial)

For local variables, after conversion After being a meaningless single character, append multiple '\xEF\xBD\xBD' characters after the variable name, and mix some other invisible characters (after 7E) into it, giving people the feeling of garbled characters. In fact, the single character does not no effect. Local variables can be named whatever you want, as long as they can be distinguished.

2. Use unicode plus escape characters to display strings, using decimal and hexadecimal formats to avoid visual viewing.

php can be used such as "\150\157\155\145\120\141\164\150" (decimal) or "\x73\x79\x73\x74\x65\x6d\x4c \x6f\x67" (hex) as variable names in files. This method directly

3, Use PHP strings to be used as function names, hiding commonly used function names

Used

$GLOBALS global variables

define macro function

base64_decode function

and custom irreversible function _kstr2() function

4 , use string connection symbols to connect the split and converted strings

The result after the _kstr2() code is restored is as follows

   function _kstr2($str) {
        $len = strlen($str);
        $result = '';
        $baseChar = ord($str[0]) - 30;
        for ($str = 1; $str < $len; $str+= 2) {
            if ($str + 1 < $len) {
                $result.= chr(ord($str[$str + 1]) + $baseChar );
                $result.= chr(ord($str[$str]) + $baseChar );
            } else {
                $result.= chr(ord($str[$str]) + $baseChar );
            }
        }
        return $result;
    }
}

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