Convert Hex Code into readable string in PHP

Question

Hi StackOverflow Community,

Here is my question, how to convert php that has hex code into readable string ? On what I mean is all inside this 2 php code..

<?php

echo "\x74\150\x69\163\x20\151\x73\40\x74\145\x73\164\x69\156\x67\40\x6f\156\x6c\171";

echo test['\x74\171\x70\145'];

echo range("\x61","\x7a");

?>

this is un-readable code, I need some php function that can convert those unreadable code into readable code..so it will become like this after convert..

<?php

echo "this is testing only";

echo test['type'];

echo range("a","z");

?>

I know i can just echo that hex to change it to readable string, but I have huge php file and lot's of php file that same like this, so I need php function that can automatically convert them all into readable code.

Thank..

'\x74\171\x70\145' != 'type' you need double quotes(") to use those escape sequences. — Musa
– Musa, Commented Dec 8, 2012 at 3:45
yes I know that, but my question is, to convert that into readable code.. "\x74\171\x70\145" != "type" become "type" != "type" so other people can understand what my code really are.. sorry if my question is bit complex.. — Mohd Shahril
– Mohd Shahril, Commented Dec 8, 2012 at 3:48

Sean Johnson · Accepted Answer · 2012-12-08 04:05:36Z

15

It seems your code is obfuscated not only with hex escape sequences, but with octal as well. I've written this function to decode it for you:

function decode_code($code){
    return preg_replace_callback(
        "@\\\(x)?([0-9a-f]{2,3})@",
        function($m){
            return chr($m[1]?hexdec($m[2]):octdec($m[2]));
        },
        $code
    );
}

See it in action here: http://codepad.viper-7.com/NjiL84

answered Dec 8, 2012 at 4:05

Sean Johnson

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1 Comment

Intuitisoft Over a year ago

use @\\(x)?([0-9a-fA-F]{2,3})@ for uppercase compatilibily

Elvin Risti · Accepted Answer · 2013-10-26 11:40:10Z

9

I had mixed content where besides hex and oct there was also normal chars.

So to update Sean's code above I added following

function decode_code($code)
{
    return preg_replace_callback('@\\\(x)?([0-9a-f]{2,3})@',
        function ($m) {
            if ($m[1]) {
                $hex = substr($m[2], 0, 2);
                $unhex = chr(hexdec($hex));
                if (strlen($m[2]) > 2) {
                    $unhex .= substr($m[2], 2);
                }
                return $unhex;
            } else {
                return chr(octdec($m[2]));
            }
        }, $code);
}

Example string

"\152\163\x6f\x6e\137d\x65\143\157\x64e"

Decoded output

"json_decode"

answered Oct 26, 2013 at 11:40

Elvin Risti

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Comments

seekers01 · Accepted Answer · 2013-07-29 02:41:34Z

2

You can use PHP's native urldecode() function to achieve this. Just pass the hex encoded string to the function and the output will be a string in readable format.

Here is a sample code to demonstrate:

<?php

echo urldecode("\x74\150\x69\163\x20\151\x73\40\x74\145\x73\164\x69\156\x67\40\x6f\156\x6c\171");

?>

This should output: this is testing only

-- seekers01

answered Jul 29, 2013 at 2:41

seekers01

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1 Comment

bryonbean Over a year ago

Beware: this is an old but incorrect answer. This is not doing what @seekers01 think it's doing. The hex in this statement is evaluated before being passed as the argument to urldecode. In other words, it's already been decoded because it is wrapped in double quotes. Try this with the hex wrapped in single quotes, it will not work.

TiGR · Accepted Answer · 2018-08-01 16:15:09Z

2

You could also use stripcslashes if there are no other escape sequences or if you don't mind converting not only hex escape sequences, but also some special characters (such as \0, \a, \b, \f, \n, \r, \t and \v).

But if you'd like to convert only hex sequences, you might use preg_replace_callback to limit what sequences should be changed, like this:

function hex2str($string) {
    return preg_replace_callback(
        '/(\\\\x[a-f\d]{2})+/i', 
        function ($matches) {
            return stripcslashes($matches[0]);
        },
        $string
    );
}

answered Aug 1, 2018 at 16:15

TiGR

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