PHP 3DES (Triple DES) Encryption

3des.php

<?php
$text = 'Super awesome string that goes through encryption';
$secret = 'D05XC051X1KLRWQ8';

$encrypted = encrypt($text, $secret);
echo "Encrypted value: $encrypted\n";

$decrypted = decrypt($encrypted, $secret);
echo "Decrypted value: $decrypted\n";

function encrypt($data, $secret) {
    $key = md5(utf8_encode($secret), true);
    $key .= substr($key, 0, 8);
    $block_size = @mcrypt_get_block_size('tripledes', 'ecb');
    $length = strlen($data);
    $pad = $block_size - ($length % $block_size);
    $data .= str_repeat(chr($pad), $pad);
    $encrypted_data = @mcrypt_encrypt('tripledes', $key, $data, 'ecb');
    return base64_encode($encrypted_data);
}

function decrypt($data, $secret) {
    $key = md5(utf8_encode($secret), true);
    $key .= substr($key, 0, 8);
    $data = base64_decode($data);
    $data = @mcrypt_decrypt('tripledes', $key, $data, 'ecb');
    $block = @mcrypt_get_block_size('tripledes', 'ecb');
    $length = strlen($data);
    $pad = ord($data[$length-1]);
    return substr($data, 0, strlen($data) - $pad);
}

This mcrypt_decrypt has been DEPRECATED as of PHP 7.1.0 and REMOVED as of PHP 7.2.0. Relying on this function is highly discouraged.

This mcrypt_decrypt has been DEPRECATED as of PHP 7.1.0 and REMOVED as of PHP 7.2.0. Relying on this function is highly discouraged.

This snippet was initially added for educational purposes and was never intended to be used in the development of web applications. After all, 3DES is a weak cipher and developers should use more modern and secure ciphers. But thanks for pointing it out that mcrypt has been entirely removed from PHP 7.2. I believe it already had some deprecation warnings when I added the snippet (hence the @ warning suppressors in front of mcrypt method calls) 😉.