Fuko\Masked

Fuko\Masked is a small PHP library for masking sensitive data: it replace blacklisted elements with their redacted values.

It is meant to be very easy to use. If you have any experience with trying to sanitise data for logging, or cleaning information that is publicly accessible, you know how annoying it is to have passwords or security token popup at various places of your dumps. Fuko\Masked is meant to help with that.

Basic use

In order to use it, you just need to feed your sensitive data (passwords, tokens, credentials) to Fuko\Masked\Protect

use Fuko\Masked\Protect;

Protect::hideValue($secret_key); // hide the value inside the $secret_key var
Protect::hideInput('password', INPUT_POST); // hide the value of $_POST['password']

$redacted = Protect::protect($_POST);

...and that's it. The blacklisted values and inputs will be masked. The output of the above code is going to be

// consider these values for the vars used
// $secret_key = '12345678';
// $_POST = array('username' => 'Bob', 'password' => 'WaldoPepper!', 'messages' => 'The secret key is 12345678');

$redacted = Protect::protect($_POST);
print_r($redacted);
/* ... and the output is
Array
(
    [username] => Bob
    [password] => ████████████
    [messages] => The secret key is ████████
)
*/

How it works ?

Fuko\Masked does two things:

• first, there is the \Fuko\Masked\Redact class which is used to mask sensitive data
• second, \Fuko\Masked\Protect class is used to collect your sensitive data, and redact it

By doing the above, you are going to have redacted content with all the sensitive details blacklisted. You do not need to go looking inside all the dumps you create for passwords or credentials, instead you just register them with \Fuko\Masked\Protect and that class will mask them wherever it finds them: strings, arrays, big text dumps. It's that simple. The idea is not to have clumsy and overdressed library, but a simple tool that its job well.

Examples

Here are several example of basic Fuko\Masked use cases.

Hide Values

You know where your passwords and credentials are, and you want to blacklist them in any dumps you create. Here's how you would do it:

use \Fuko\Masked\Protect;

// consider these values inside $config
// $config = array(
// 	'project_title' => 'My New Project!',
// 	'mysql_username' => 'me',
// 	'mysql_password' => 'Mlyk!',
// 	'mysql_database' => 'project',
// 	'root' => '/var/www/niakade/na/majnata/si',
// 	'i.am.stupid' => 'Mlyk! e egati parolata za moya project',
// 	);

Protect::hideValue($config['mysql_username']);
Protect::hideValue($config['mysql_password']);
Protect::hideValue($config['mysql_database']);

print_r(Protect::protect($config));
/* ... and the output is
Array
(
    [project_title] => My New Project!
    [mysql_username] => ██
    [mysql_password] => █████
    [mysql_database] => ███████
    [root] => /var/www/niakade/na/majnata/si
    [i.am.stupid] => █████ e egati parolata za moya ███████
)
*/

The sensitive details might be in some nested arrays within the arrays, they are still going to be redacted:

use \Fuko\Masked\Protect;

Protect::hideValue($password);

$a = ['b' => ['c' => ['d' => $password]]];
print_r(Protect::protect($a));
/* ... and the output is
Array
(
    [b] => Array
        (
            [c] => Array
                (
                    [d] => ██████
                )
        )
)
*/

Hide Inputs

At some occasions you know that user-submitted data or other super-global inputs might contain sensitive data. In these cases you do not need to hide the actual value, but you can address the input array instead. In this example we are going to mask the "password" POST value:

use \Fuko\Masked\Protect;

Protect::hideInput('password', INPUT_POST);

// later you need to do a dump of $_POST and ...
$_POST_redacted = Protect::protect($_POST);
/* ... and the output is
Array
(
    [email] => [email protected]
    [password] => ███████
)
*/

Working with Objects

The \Fuko\Masked\Protect::protect() only works with strings and arrays. If you need to mask the sensitive data in an object dump, you first create the dump and then feed it to Protect::protect(), like this:

use \Fuko\Masked\Protect;

Protect::hideValue($password);
$a = new stdClass;
$a->b = new stdClass;
$a->b->c = new stdClass;
$a->password = $a->b->secret = $a->b->c->d = $password;
echo Protect::protect(print_r($a, true));
/* ... and the output is
stdClass Object
(
    [b] => stdClass Object
        (
            [c] => stdClass Object
                (
                    [d] => ██████████████████
                )
            [secret] => ██████████████████
        )
    [password] => ██████████████████
)
*/

For those classes that have ::__toString() method implemented, the objects will be cast into strings with that. Here is an example with an exception, and exception classes have that:

use \Fuko\Masked\Protect;

Protect::hideValue($password);
$e = new \Exception('Look, look, his password is ' . $password);

echo Protect::protect($e);
/* ... and the output is
Exception: Look, look, his password is ████████ in /tmp/egati-probata.php:123
Stack trace:
#0 {main}
*/

Different Masking

You can use \Fuko\Masked\Redact in your project as the library for masking data. By default the class uses \Fuko\Masked\Redact::disguise() method for masking, with default settings that masks everything and that uses █ as masking symbol. Here's how you can change its behaviour:

use \Fuko\Masked\Redact;

/* leave 4 chars unmasked at the end, and use '*' as masking symbol */
Redact::setRedactCallback( [Redact::class, 'disguise'], [4, '*']);
echo Redact::redact('1234567890'); // Output is '******7890'

/* leave 4 chars unmasked at the beginning, and use '🤐' as masking symbol */
Redact::setRedactCallback( [Redact::class, 'disguise'], [-4, '🤐']);
echo Redact::redact('1234567890'); // Output is '1234🤐🤐🤐🤐🤐🤐'

You can set your own callback for masking with \Fuko\Masked\Redact class:

use \Fuko\Masked\Redact;

Redact::setRedactCallback( function($var) { return '💩'; } );
echo Redact::redact('1234567890'); // Output is '💩'