New encryption with Gravity Forms

functions.php

<?php

function my_custom_gravityforms_encrypt( $to_encrypt )
{
	if ( '' === $to_encrypt ) return null;
	
	if ( function_exists('openssl_encrypt') && function_exists('openssl_random_pseudo_bytes') )
	{
		$iv = openssl_random_pseudo_bytes( openssl_cipher_iv_length( 'aes-256-cbc' ) );
		$encrypted = openssl_encrypt( $to_encrypt, 'aes-256-cbc', MY_CUSTOM_GF_ENCRYPTION_KEY, 0, $iv );
    
		return base64_encode( $encrypted . '::' . $iv );
	}
	
	return base64_encode( $to_encrypt );
} // end my_custom_gravityforms_encrypt



function my_custom_gravityforms_decrypt( $to_decrypt )
{
	if ( '' === $to_decrypt ) return null;
	
	if ( function_exists('openssl_decrypt') )
	{
		@list( $encrypted_data, $iv ) = explode( '::', base64_decode( $to_decrypt ), 2 );
		
    	return openssl_decrypt( $encrypted_data, 'aes-256-cbc', MY_CUSTOM_GF_ENCRYPTION_KEY, 0, $iv );
    }
    
    return base64_decode( $to_decrypt );
} // end my_custom_gravityforms_decrypt

usage.php

<?php

/**
 * Encrypt all values for GF entries
**/
add_filter( 'gform_save_field_value', 'gf_custom_save_field_value', 10, 4 );
function gf_custom_save_field_value( $value, $lead, $field, $form )
{
    my_custom_gravityforms_encrypt( $value );
}
// end gf_custom_save_field_value


/**
 * Decrypting based on date of implementation for encryption
**/
add_filter( 'gform_get_input_value', 'gf_custom_decode_field', 10, 4 );
function gf_custom_decrypt_field( $value, $entry, $field, $input_id )
{
    # Add a check to see if a field has to be decrypted, 
    # because it's possible you're adding this after already having entries
    
    $date_implemented = '2019-01-23 10:36:00'; # format: yyyy-mm-dd hh:mi:ss
    $date_entry = rgar( $entry, 'date_created' );
    
    # Entry is from after implementing encrypting entries
    if ( strtotime( $date_entry ) >= $date_implemented )
        return my_custom_gravityforms_decrypt( $value );
    
    # Entry is from before implementing encrypting entries
    return $value;
}
// end gf_custom_decrypt_field


/**
 * Or: always decrypt
**/
add_filter( 'gform_get_input_value', 'gf_custom_decode_field', 10, 4 );
function gf_custom_decrypt_field( $value, $entry, $field, $input_id )
{
    return my_custom_gravityforms_decrypt( $value );
}
// end gf_custom_decrypt_field

wp-config.php

define('MY_CUSTOM_GF_ENCRYPTION_KEY','JuSt4fEwCuSt0McHarAc73RSf0rD3M0pUrP05e5!'); # do change it to your own custom key ;-)