A Wordpress plugin to enable encrypting and decrypting of data entered using Formidable Forms. Requires Advanced Custom Fields (ACF) Plugin. Based upon original code by Victor Font.

The following lines need to be added to wp-config.php, substituting the strings as described below.

define('FORMIDABLE_SALT', 'string);
define('FORMIDABLE_METHOD', 'string');
define('FORMIDABLE_OPTIONS', 0);
define('FORMIDABLE_IV', 'string');

Generate a SALT value (choose any one and rename FORMIDABLE_SALT).

Choose an appropriate encryption method. e.g. AES-256-CBC

Is 0, here’s an explanation of openssl options.

“A non-NULL Initialization Vector” of a particular length according to chosen encryption method

“a random string with a length that must match the length required by your chosen cipher method. How do we know the iv length required by the chosen cipher method? We use the openssl_cipher_iv_length($cipher) function to find out.”

More details in this blog post.