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Mahmoud's Encryption/Decryption Demo

GOTO Decrypt

To understand more about this Encryption method (AES-256-CBC) see: Review this article.

"AES would take billions of years to break using current computing technology. Hackers would be foolish to even attempt this [brute-force] type of attack." -- taken from above article

CODE FOLLOWS


<?php

include('includes/header.php');



// code

error_reporting(E_ALL);    // set error reporting to all

$self = basename($_SERVER['SCRIPT_NAME']);



$string = isset($_POST['string']) ? $_POST['string'] : "Now is the time.";



$action = 'encrypt';

$encrypted = encrypt_decrypt($action, $string);



?>



    <h1> Mahmoud's Encryption/Decryption Demo</h1>



    <form action="<?php echo($self); ?>" method="POST">



        <fieldset>

            <legend>String to be Encrypted</legend>

            <textarea rows="10" cols="120" type="text" name="string" value="<?php echo($string); ?>">

<?php echo($string); ?>

</textarea>

            <br>

        </fieldset>



        <br> <br>



        <fieldset>

            <legend>Encrypted String</legend>

            <textarea rows="10" cols="120" type="text" name="encrypted" value="">

<?php echo($encrypted); ?>

</textarea>

            <br>

        </fieldset>



        <p>

            <input type="submit" name="submit" value="Encrypt">

        </p>



    </form>



    <a href="decrypt.php">GOTO Decrypt</a>



    <p>

        To understand more about this Encryption method (AES-256-CBC) see:

        <a href="https://www.n-able.com/blog/aes-256-encryption-algorithm"> Review this article. </a>

    </p>



    <p>

    <div class="blue">

        "AES would take billions of years to break using current computing technology.

        Hackers would be foolish to even attempt this [brute-force] type of attack." -- taken from above article

    </div>



    </p>



<?php



// ======== functions ============



function encrypt_decrypt($action, $string)

{



    $output = false;

    $encrypt_method = "AES-256-CBC";



    // the following two values should be changed for your personal use.



    $secret_key = 'Epur si muove';

    $secret_iv = 'non sum qualis eram';



    // hash

    $key = hash('sha256', $secret_key);



    // encrypt method AES-256-CBC expects 16 bytes.

    $iv = substr(hash('sha256', $secret_iv), 0, 16);



    if ($action == 'encrypt')

    {

        $output = base64_encode(openssl_encrypt($string, $encrypt_method, $key, 0, $iv));

    }

    else

    {

        if ($action == 'decrypt')

        {

            $output = openssl_decrypt(base64_decode($string), $encrypt_method, $key, 0, $iv);

        }

    }

    return $output;

}



include('includes/footer.php');

?>

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